US20150071104A1

US20150071104A1 - Autonomously selecting a communication channel having a co-channel operation constraint

Info

Publication number: US20150071104A1
Application number: US14/483,500
Authority: US
Inventors: Cong Shen; Tao Chen; Farhad Meshkati
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2013-09-12
Filing date: 2014-09-11
Publication date: 2015-03-12
Also published as: US20150072697A1; WO2015038845A2; WO2015038845A3; WO2015038847A1; US9369900B2

Abstract

Provided are methods and apparatus for selecting a communication channel. The methods and apparatus select a channel having the least interference and minimize a number of different channels in use. For example, a method for selecting a communication channel includes measuring a transmission characteristic for each channel in a plurality of channels to create a transmission characteristic measurement for each channel. The method also includes receiving, from at least one neighboring access point, data indicating the neighboring access point uses a channel in the plurality of channels. A utility value for each channel in the plurality of channels is calculated by weighting, based on the number of the neighboring access points using each channel in the plurality of channels, the transmission characteristic measurement for each channel in the plurality of channels. Further, the channel having the highest or the lowest utility value is chosen as the communication channel.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application for patent claims priority to United States Provisional Patent Application No. 61/877,164 entitled “AUTONOMOUS CELL CHANNEL SELECTION METHOD AND APPARATUS WITH CO-CHANNEL OPERATION CONSTRAINT” filed Sep. 12, 2013; U.S. Provisional Patent Application No. 61/918,741 entitled “AUTONOMOUS CELL CHANNEL SELECTION METHOD AND APPARATUS WITH CO-CHANNEL OPERATION CONSTRAINT” filed Dec. 20, 2013; and U.S. Provisional Patent Application No. 61/933,680 entitled “USER EQUIPMENT-ASSISTED CHANNEL SELECTION METHOD AND APPARATUS WITH CO-CHANNEL OPERATION CONSTRAINT” filed Jan. 30, 2014, each of which is assigned to the assignee hereof and hereby expressly incorporated by reference herein.

REFERENCE TO CO-PENDING APPLICATIONS FOR PATENT

The present application for patent is also related to the following co-pending U.S. patent application: “SELECTING A COMMUNICATION CHANNEL BASED ON A NEIGHBORING CELL CONSTRAINT,” having Attorney Docket No. QC134865U2, filed concurrently herewith, assigned to the assignee hereof, and expressly incorporated herein by reference in its entirety.

INTRODUCTION

This disclosure relates generally to electronics, and more specifically, but not exclusively, to a method and apparatus for autonomously selecting a communication channel having a co-channel constraint.
Wireless communication systems are widely deployed to provide various types of communication content, such as voice, data, and so on. Typical wireless communication systems are multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and others. These systems are often deployed in conformity with specifications such as third generation partnership project (3GPP), 3GPP long term evolution (LTE), ultra mobile broadband (UMB), evolution data optimized (EV-DO), and the like.
In cellular networks, macro scale access points (or macro NodeBs (MNBs)) provide connectivity and coverage to a large number of users over a certain geographical area. A macro network deployment is carefully planned, designed, and implemented to offer good coverage over the geographical region. Even such careful planning, however, cannot fully accommodate channel characteristics such as fading, multipath, shadowing, etc., especially in indoor environments. Indoor users therefore often face coverage issues (e.g., call outages and quality degradation) resulting in a poor experience by the users.
To extend cellular coverage indoors, such as for residential homes and office buildings, additional small coverage, typically low-power access points have recently begun to be deployed to supplement conventional macro networks, providing more robust wireless coverage for mobile devices. These small coverage access points are commonly referred to as neighborhood small cells (NSCs), Home NodeBs or Home eNBs (collectively, H(e)NBs), femto nodes, femtocells, femtocell access points, pico nodes, micro nodes, etc., and are deployed for incremental capacity growth, richer user experience, in-building or other specific geographic coverage, and so on. Such small coverage access points can be connected to the Internet and the mobile network operator's network, for example, via a digital subscriber line (DSL) router, a cable modem, and/or a fiber optic line.
Operators of access points must assign channels to access devices that are permitted to associate with a respective access point. Conventionally, neighboring access points do not coordinate channel assignments. For example, consider a mobile network operator who has N total channels for the operator's access points (e.g., access points (femto, pico, micro, etc.)) from which to select for a specific service. The operator also has other services that can occupy some or all of these same channels at different geographical locations. Hence, a dynamic channel selection method and apparatus are needed. There is a need for a dynamic channel selection method and apparatus that selects a channel having the least interference (e.g., interference emanating from non-LTE sources such as WiFi sources, etc.), such that the access points have the best performance in terms of coverage and capacity, as well as that has as many access points operating on the same channel as possible (i.e., to minimize a percentage of access points that operate on channels that are different than the majority). This would improve mobility management over conventional techniques, as intra-frequency measurement is much less costly than inter-frequency measurement.
Accordingly, there are long-felt industry needs for methods and apparatus that improve upon conventional methods and apparatus, including the improved methods and apparatus provided hereby.

SUMMARY

This summary provides a basic understanding of some aspects of the present teachings. This summary is not exhaustive in detail, and is neither intended to identify all critical features, nor intended to limit the scope of the claims.
The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects disclosed.
Exemplary methods and apparatus for selecting a communication channel to use are provided. An exemplary method includes measuring a transmission characteristic for each channel in a plurality of channels to create a transmission characteristic measurement for each channel; receiving, from at least one neighboring access point, data indicating the neighboring access point uses a channel in the plurality of channels; calculating a utility value for each channel in the plurality of channels by weighting, based on the number of the neighboring access points using each channel in the plurality of channels, the transmission characteristic measurement for each channel in the plurality of channels; and choosing the channel having the highest utility value or the lowest utility value as the communication channel to use for the transmitting. The measured transmission characteristic can be at least one of a received signal strength indication or a reference signal received power. The measuring can be performed multiple times for the at least one channel in the plurality of channels, and the method can further include at least one of determining a median of the measured respective transmission characteristics for the at least one channel in the plurality of channels, determining a percentile of the measured respective transmission characteristics for the at least one channel in the plurality of channels, or averaging, over time, the measured respective transmission characteristics for the at least one channel in the plurality of channels. The calculating can use the following equation to determine the utility value (U_n) for a channel (n) in the plurality of channels:
U _n=−(M _n −K _n*Δ)
where:
M_n=the transmission characteristic measurement for the channel,
K_n=the number of neighboring access points using the channel, and
Δ=an amount to bias the transmission characteristic measurement for each neighboring access point using the channel.
In a further example, provided is a non-transitory computer-readable medium, having at least one instruction stored thereon that, if executed by a processor, such as a special-purpose processor, cause the processor to execute at least a part of the aforementioned method. The non-transitory computer-readable medium can be integrated with a device, such as a mobile device, a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant, a fixed location data unit, and/or a computer.
In another example, provided is an apparatus configured to select a communication channel to use. The apparatus includes means for measuring a transmission characteristic for each channel in a plurality of channels to create a transmission characteristic measurement for each channel; means for receiving, from at least one neighboring access point, data indicating the neighboring access point uses a channel in the plurality of channels; means for calculating a utility value for each channel in the plurality of channels by weighting, based on the number of the neighboring access points using each channel in the plurality of channels, the transmission characteristic measurement for each channel in the plurality of channels; and means for choosing the channel having the highest utility value or the lowest utility value as the communication channel to use for the transmitting. The measured transmission characteristic can be at least one of a received signal strength indication or a reference signal received power. The apparatus can be configured to perform the measuring multiple times for the at least one channel in the plurality of channels, and the apparatus can be further configured to at least one of determine a median of the measured respective transmission characteristics for the at least one channel in the plurality of channels, determine a percentile of the measured respective transmission characteristics for the at least one channel in the plurality of channels, or average, over time, the measured respective transmission characteristics for the at least one channel in the plurality of channels. The apparatus can be configured to use the following equation to determine the utility value (U_n) for a channel (n) in the plurality of channels:
U _n=−(M _n −K _n*Δ)
where:
M_n=the transmission characteristic measurement for the channel,
K_n=the number of neighboring access points using the channel, and
Δ=an amount to bias the transmission characteristic measurement for each neighboring access point using the channel.
At least a part of the apparatus can be integrated in a semiconductor die. Further, at least a part of the apparatus can be a part of a device, such as a mobile device, a set top box, a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant, a fixed location data unit, and/or a computer. In a further example, provided is a non-transitory computer-readable medium, having at least one instruction stored thereon that, if executed by a lithographic device, cause the lithographic device to fabricate at least a part of the apparatus.
In another example, provided is an apparatus configured to select a communication channel to use. The apparatus includes a processor configured to measure a transmission characteristic for each channel in a plurality of channels to create a transmission characteristic measurement for each channel; receive, from at least one neighboring access point, data indicating the neighboring access point uses a channel in the plurality of channels; calculate a utility value for each channel in the plurality of channels by weighting, based on the number of the neighboring access points using each channel in the plurality of channels, the transmission characteristic measurement for each channel in the plurality of channels; and choose the channel having the highest utility value or the lowest utility value as the communication channel to use for the transmitting. The measured transmission characteristic can be at least one of a received signal strength indication or a reference signal received power. The processor can be configured to perform the measuring multiple times for the at least one channel in the plurality of channels, and the processor can be further configured to at least one of determine a median of the measured respective transmission characteristics for the at least one channel in the plurality of channels, determine a percentile of the measured respective transmission characteristics for the at least one channel in the plurality of channels, or average, over time, the measured respective transmission characteristics for the at least one channel in the plurality of channels. The processor can be configured to use the following equation to determine the utility value (U_n) for a channel (n) in the plurality of channels:
U _n=−(M _n −K _n*Δ)
where:
M_n=the transmission characteristic measurement for the channel,
K_n=the number of neighboring access points using the channel, and
Δ=an amount to bias the transmission characteristic measurement for each neighboring access point using the channel.
At least a part of the apparatus can be integrated on a semiconductor die. The apparatus can further include at least one of a mobile device, an access point, a communications device, a personal digital assistant, a fixed location data unit, or a computer with which the processor is integrated. In a further example, provided is a non-transitory computer-readable medium, having at least one instruction stored thereon that, if executed by a lithographic device, cause the lithographic device to fabricate at least a part of the apparatus.
Exemplary methods and apparatus for choosing a communication channel are provided. An exemplary method includes arranging a candidate channel list to reflect a priority of each communication channel in the candidate channel list; evaluating, in order by priority, a candidate communication channel in the candidate channel list, where the evaluating is based on at least one of a transmission characteristic of the candidate channel or received data from at least one access point; and selecting, based on results of the evaluating, the candidate communication channel as the chosen communication channel. The selecting can be based on the transmission characteristic and the evaluating can further include measuring a respective transmission characteristic of the candidate channel to create a respective transmission characteristic measurement of the candidate channel; determining if the respective transmission characteristic measurement is within a range; and selecting, if the respective transmission characteristic measurement is within the range, the candidate communication channel as the chosen communication channel. The measuring the respective transmission characteristic can be stopped after selecting the chosen communication channel. The respective transmission characteristic can be a received signal strength indication of the candidate channel. The range can be less than a received signal strength indication operational threshold. The evaluating can further include performing the following when the respective transmission characteristic measurement is not within the range: checking if a number of neighboring cells on the candidate channel is greater than a threshold number of neighboring cells; selecting, if the number of neighboring cells on the candidate channel is greater than the threshold number of neighboring cells, the candidate channel as the chosen communication channel; and repeating the evaluating using a subsequent candidate channel in the channel candidate list, if the number of neighboring cells on the candidate channel is not greater than the threshold number of neighboring cells. The method can further include selecting the candidate channel having the lowest received signal strength indication as the chosen communication channel when all channels in the candidate channel list have been evaluated, and none of the candidate channels have been selected as the chosen communication channel. The selecting can be based on the received data and the evaluating can further include: receiving, from at least the one access point, channel use data indicating that the at least one access point is capable of using the candidate communication channel; if the at least one access point is capable of using the candidate communication channel, then the candidate communication channel is selected as the chosen communication channel; and at least one access point is not capable of using the candidate communication channel, then the evaluating is repeated using a subsequent candidate channel in the channel candidate list. The evaluating for a subsequent candidate channel in the channel candidate list can be repeated until the chosen communication channel is selected. The method can further include determining if a preferred channel is in the candidate channel list, where the arranging includes setting the preferred channel as a higher priority communication channel in the candidate channel list, when the preferred channel is in the candidate channel list. The method can further include at least one of transmitting data or receiving data via the chosen communication channel.
In a further example, provided is a non-transitory computer-readable medium, having at least one instruction stored thereon that, if executed by a processor, such as a special-purpose processor, cause the processor to execute at least a part of the aforementioned method. The non-transitory computer-readable medium can be integrated with a device, such as a mobile device, a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant, a fixed location data unit, and/or a computer.
In another example, provided is an apparatus configured to choose a communication channel. The apparatus includes means for arranging a candidate channel list to reflect a priority of each communication channel in the candidate channel list; means for evaluating, in order by priority, a candidate communication channel in the candidate channel list, where the evaluating is based on at least one of a transmission characteristic of the candidate channel or received data from at least one access point; and means for selecting, based on results of the evaluating, the candidate communication channel as the chosen communication channel. The selecting can be based on the transmission characteristic and the means for evaluating can further include means for measuring a respective transmission characteristic of the candidate channel to create a respective transmission characteristic measurement of the candidate channel; means for determining if the respective transmission characteristic measurement is within a range; and means for selecting, if the respective transmission characteristic measurement is within the range, the candidate communication channel as the chosen communication channel. The measuring the respective transmission characteristic can be stopped after selecting the chosen communication channel. The respective transmission characteristic can be a received signal strength indication of the candidate channel. The range can be less than a received signal strength indication operational threshold. The means for evaluating can further include means for performing the following when the respective transmission characteristic measurement is not within the range: checking if a number of neighboring cells on the candidate channel is greater than a threshold number of neighboring cells; selecting, if the number of neighboring cells of the candidate channel is greater than the threshold number of neighboring cells, the candidate channel as the chosen communication channel; and repeating the evaluating using a subsequent candidate channel in the channel candidate list, if the number of neighboring cells on the candidate channel is not greater than the threshold number of neighboring cells. The apparatus can further include means for selecting the candidate channel having the lowest received signal strength indication as the chosen communication channel when all channels in the candidate channel list have been evaluated, and none of the candidate channels have been selected as the chosen communication channel. The selecting can be based on the received data and the means for evaluating can further include: means for receiving, from at least the one access point, channel use data indicating that the at least one access point is capable of using the candidate communication channel; means for determining if the at least one access point is capable of using the candidate communication channel, and means for then selecting the candidate communication channel is as the chosen communication channel; and means for determining if at least one access point is not capable of using the candidate communication channel, and means for repeating the evaluating using a subsequent candidate channel in the channel candidate list. The evaluating for a subsequent candidate channel in the channel candidate list can be repeated until the chosen communication channel is selected. The apparatus can further include means for determining if a preferred channel is in the candidate channel list, where the means for arranging includes means for setting the preferred channel as a higher priority communication channel in the candidate channel list, when the preferred channel is in the candidate channel list. The apparatus can further include means for at least one of transmitting data or receiving data via the chosen communication channel.
At least a part of the apparatus can be integrated in a semiconductor die. Further, at least a part of the apparatus can be a part of a device, such as a mobile device, a set top box, a music player, a video player, an entertainment unit, a navigation device, a communications device, a personal digital assistant, a fixed location data unit, and/or a computer. In a further example, provided is a non-transitory computer-readable medium, having at least one instruction stored thereon that, if executed by a lithographic device, cause the lithographic device to fabricate at least a part of the apparatus.
In another example, provided is an apparatus configured to choose a communication channel. The apparatus includes a special-purpose processor configured to arrange a candidate channel list to reflect a priority of each communication channel in the candidate channel list; evaluate, in order by priority, a candidate communication channel in the candidate channel list, where the evaluating is based on at least one of a transmission characteristic of the candidate channel or received data from at least one access point; and select, based on results of the evaluating, the candidate communication channel as the chosen communication channel. The processor can be configured to select based on the transmission characteristic and can be configured to: measure a respective transmission characteristic of the candidate channel to create a respective transmission characteristic measurement of the candidate channel; determine if the respective transmission characteristic measurement is within a range; and select, if the respective transmission characteristic measurement is within the range, the candidate communication channel as the chosen communication channel. The measuring the respective transmission characteristic can be stopped after selecting the chosen communication channel. The respective transmission characteristic can be a received signal strength indication of the candidate channel. The range can be less than a received signal strength indication operational threshold. The processor can be configured to performing the following when the respective transmission characteristic measurement is not within the range: checking if a number of neighboring cells on the candidate channel is greater than a threshold number of neighboring cells; selecting, if the number of neighboring cells on the candidate channel is greater than the threshold number of neighboring cells, the candidate channel as the chosen communication channel; and repeating the evaluating using a subsequent candidate channel in the channel candidate list, if the number of neighboring cells on the candidate channel is not greater than the threshold number of neighboring cells. The processor is configured to select the candidate channel having the lowest received signal strength indication as the chosen communication channel when all channels in the candidate channel list have been evaluated, and none of the candidate channels have been selected as the chosen communication channel. The processor can be configured to select based on the received data and can be configured to: receive, from at least the one access point, channel use data indicating that the at least one access point is capable of using the candidate communication channel; select, when the at least one access point is capable of using the candidate communication channel, the candidate communication channel as the chosen communication channel; and repeat the evaluating using a subsequent candidate channel in the channel candidate list when the at least one access point is not capable of using the candidate communication channel. The processor can be configured to: determine if a preferred channel is in the candidate channel list; and set the preferred channel as a higher priority communication channel in the candidate channel list, when the preferred channel is in the candidate channel list. The processor can be configured to at least one of transmit data or receive data via the chosen communication channel. The apparatus can further include at least one of a mobile device, an access point, a communications device, a personal digital assistant, a fixed location data unit, or a computer with which the processor is integrated.
At least a part of the apparatus can be integrated on a semiconductor die. In a further example, provided is a non-transitory computer-readable medium, having at least one instruction stored thereon that, if executed by a lithographic device, cause the lithographic device to fabricate at least a part of the apparatus.
The foregoing broadly outlines some of the features and technical advantages of the present teachings in order that the detailed description and drawings can be better understood. Additional features and advantages are also described in the detailed description. The conception and disclosed examples can be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present teachings. Such equivalent constructions do not depart from the technology of the teachings as set forth in the claims. The inventive features that are characteristic of the teachings, together with further objects and advantages, are better understood from the detailed description and the accompanying figures. Each of the figures is provided for the purpose of illustration and description only, and does not limit the present teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are presented to describe examples of the present teachings, and are not limiting.

FIG. 1 illustrates an example mixed-deployment wireless communication system including macro cell base stations and small cell base stations.

FIG. 2 illustrates an example small cell base station with co-located radio components (e.g., LTE and Wi-Fi).

FIG. 3 depicts an exemplary method for channel selection.

FIGS. 4A-C depict another exemplary method for channel selection.

FIG. 5 is a simplified block diagram of several sample aspects of components that may be employed in communication nodes and configured to support communication as taught herein.

FIGS. 6-7 are other simplified block diagrams of several sample aspects of apparatuses configured to support communication as taught herein.

FIG. 8 illustrates an example communication system environment in which the teachings and structures herein may be incorporated.

In accordance with common practice, the features depicted by the drawings may not be drawn to scale. Accordingly, the dimensions of the depicted features may be arbitrarily expanded or reduced for clarity. In accordance with common practice, some of the drawings are simplified for clarity. Thus, the drawings may not depict all components of a particular apparatus or method. Further, like reference numerals denote like features throughout the specification and figures.

DETAILED DESCRIPTION

Provided are methods and apparatus that select a communication channel by using a distributed solution with a co-channel operation constraint. In an example, an autonomous channel selection method is provided, so an access point (e.g., an access point) selects a channel of operation without receiving a channel assignment from a higher-level network management device.
To select a channel from a plurality of channels, the methods and apparatus use a measured transmission characteristic (e.g., a received signal strength indication (RSSI)), as well as data indicating neighboring access point usage of at least one channel in the plurality of channels. A Network Listen (NL) technique can be used to obtain the channel usage distribution of other neighboring access points (e.g., access points) in the region near the cell performing the channel selection method. The channel usage distribution data can be used to weigh the measured transmission characteristic in order to achieve a balance of minimizing interference from other neighboring access points and maximizing the number of access points operating on the same channel.
The exemplary apparatuses and methods disclosed herein advantageously address the long-felt industry needs, as well as other previously unidentified needs, and mitigate shortcomings of the conventional methods and apparatus. For example, an advantage provided by the disclosed apparatuses and methods herein is an improvement in cost savings, energy savings, and time savings over conventional devices. Other advantages include a reduction in time, energy, and expense of handing off a device from an access point. The exemplary apparatuses and methods disclosed herein also improve mobility management, as intra-frequency measurement is much less costly than inter-frequency measurement.
More specific aspects of the disclosure are provided in the following description and related drawings directed to various examples provided for illustration purposes. Alternate aspects may be devised without departing from the scope of the disclosure. Additionally, well-known aspects of the disclosure may not be described in detail or may be omitted so as not to obscure more relevant details.
Those of skill in the art will appreciate that the information and signals described below may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description below may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof, depending in part on the particular application, in part on the desired design, in part on the corresponding technology, etc.
Further, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that various actions described herein can be performed by specific circuits (e.g., Application Specific Integrated Circuits (ASICs)), by program instructions being executed by one or more processors, or by a combination of both. In addition, for each of the aspects described herein, the corresponding form of any such aspect may be implemented as, for example, “logic configured to” perform the described action.
In this description, certain terminology is used to describe certain features. The term “mobile device” can describe, and is not limited to, a user device, a mobile phone, a mobile communication device, a pager, a personal digital assistant, a personal information manager, a mobile hand-held computer, a laptop computer, a wireless device, a wireless modem, and/or other types of portable electronic devices typically carried by a person and/or having communication capabilities (e.g., wireless, cellular, infrared, short-range radio, etc.). Further, the terms “user equipment” (UE), “mobile terminal,” “mobile device,” and “wireless device,” can be interchangeable.
As used herein, an access point providing coverage over a relatively large area is usually referred to as a macro access point, while an access point that provides coverage over a relatively small area (e.g., a residence) is usually referred to as a small cell access point. Intermediate access points that provide coverage over an area smaller than a macro area but larger than a small cell area are usually referred to as pico access points (e.g., providing coverage within a commercial building). For convenience, the various functions described this disclosure can be scaled for use by any of these types of access points. A cell associated with a macro access point, a small cell access point, or a pico access point can be referred to as a macrocell, a small cell, or a picocell, respectively. In some system implementations, each cell can be further associated with (e.g., divided into) one or more sectors.
In some examples, other terminology can be used to reference a macro access point, a small cell access point, a pico access point, a user device, and other devices. The use of such terms is generally not intended to invoke or exclude a particular technology in relation to the aspects described or otherwise facilitated by the description herein. For example, a macro access point can be configured or alternatively referred to as a macro node, macro access point, NodeB, evolved NodeB (eNodeB), macrocell, and so on. A small cell access point can be configured or alternatively referred to as a small cell node, small cell access point, Home NodeB, Home eNodeB, femtocell, a access point, and so on. A user device can be configured or alternatively referred to as a device, user equipment (UE), subscriber unit, subscriber station, mobile station, mobile device, access terminal, and so on. For convenience, this disclosure described various functions in the context of generic “access points” and “access devices,” which, unless otherwise indicated by the particular context of the description, are intended to cover the corresponding technology and terminology in all wireless systems.
FIG. 1 illustrates an example mixed-deployment wireless communication system, in which small cell base stations are deployed in conjunction with and to supplement the coverage of macro cell base stations. As used herein, small cells generally refer to a class of low-powered base stations that may include or be otherwise referred to as femto cells, pico cells, micro cells, etc. As noted in the background above, they may be deployed to provide improved signaling, incremental capacity growth, richer user experience, and so on.
The illustrated wireless communication system 100 is a multiple-access system that is divided into a plurality of cells 102 and configured to support communication for a number of users. Communication coverage in each of the cells 102 is provided by a corresponding base station 110, which interacts with one or more user devices 120 via DownLink (DL) and/or UpLink (UL) connections. In general, the DL corresponds to communication from a base station to a user device, while the UL corresponds to communication from a user device to a base station.
As will be described in more detail below, these different entities may be variously configured in accordance with the teachings herein to provide or otherwise support the features discussed briefly above. For example, one or more of the small cell base stations 110 may include a BS-side management module 112, while one or more of the user devices 120 may include a UE-side management module 122.
As used herein, the terms “user device” and “base station” are not intended to be specific or otherwise limited to any particular Radio Access Technology (RAT), unless otherwise noted. In general, such user devices may be any wireless communication device (e.g., a mobile phone, router, personal computer, server, etc.) used by a user to communicate over a communications network, and may be alternatively referred to in different RAT environments as an Access Terminal (AT), a Mobile Station (MS), a Subscriber Station (STA), a User Equipment (UE), etc. Similarly, a base station may operate according to one of several RATs in communication with user devices depending on the network in which it is deployed, and may be alternatively referred to as an Access Point (AP), a Network Node, a NodeB, an evolved NodeB (eNB), etc. In addition, in some systems a base station may provide purely edge node signaling functions while in other systems it may provide additional control and/or network management functions.
Returning to FIG. 1, the different base stations 110 include an example macro cell base station 110A and two example small cell base stations 110B, 110C. The macro cell base station 110A is configured to provide communication coverage within a macro cell coverage area 102A, which may cover a few blocks within a neighborhood or several square miles in a rural environment. Meanwhile, the small cell base stations 110B, 110C are configured to provide communication coverage within respective small cell coverage areas 102B, 102C, with varying degrees of overlap existing among the different coverage areas. In some systems, each cell may be further divided into one or more sectors (not shown).
Turning to the illustrated connections in more detail, the user device 120A may transmit and receive messages via a wireless link with the macro cell base station 110A, the message including information related to various types of communication (e.g., voice, data, multimedia services, associated control signaling, etc.). The user device 120B may similarly communicate with the small cell base station 110B via another wireless link, and the user device 120C may similarly communicate with the small cell base station 110C via another wireless link. In addition, in some scenarios, the user device 120C, for example, may also communicate with the macro cell base station 110A via a separate wireless link in addition to the wireless link it maintains with the small cell base station 110C.
As is further illustrated in FIG. 1, the macro cell base station 110A may communicate with a corresponding wide area or external network 130, via a wired link or via a wireless link, while the small cell base stations 110B, 110C may also similarly communicate with the network 130, via their own wired or wireless links. For example, the small cell base stations 110B, 110C may communicate with the network 130 by way of an Internet Protocol (IP) connection, such as via a Digital Subscriber Line (DSL, e.g., including Asymmetric DSL (ADSL), High Data Rate DSL (HDSL), Very High Speed DSL (VDSL), etc.), a TV cable carrying IP traffic, a Broadband over Power Line (BPL) connection, an Optical Fiber (OF) cable, a satellite link, or some other link.
The network 130 may comprise any type of electronically connected group of computers and/or devices, including, for example, Internet, Intranet, Local Area Networks (LANs), or Wide Area Networks (WANs). In addition, the connectivity to the network may be, for example, by remote modem, Ethernet (IEEE 802.3), Token Ring (IEEE 802.5), Fiber Distributed Datalink Interface (FDDI) Asynchronous Transfer Mode (ATM), Wireless Ethernet (IEEE 802.11), Bluetooth (IEEE 802.15.1), or some other connection. As used herein, the network 130 includes network variations such as the public Internet, a private network within the Internet, a secure network within the Internet, a private network, a public network, a value-added network, an intranet, and the like. In certain systems, the network 130 may also comprise a Virtual Private Network (VPN).
Accordingly, it will be appreciated that the macro cell base station 110A and/or either or both of the small cell base stations 110B, 110C may be connected to the network 130 using any of a multitude of devices or methods. These connections may be referred to as the “backbone” or the “backhaul” of the network, and may in some implementations be used to manage and coordinate communications between the macro cell base station 110A, the small cell base station 110B, and/or the small cell base station 110C. In this way, as a user device moves through such a mixed communication network environment that provides both macro cell and small cell coverage, the user device may be served in certain locations by macro cell base stations, at other locations by small cell base stations, and, in some scenarios, by both macro cell and small cell base stations.
For their wireless air interfaces, each base station 110 may operate according to one of several RATs depending on the network in which it is deployed. These networks may include, for example, Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, Single-Carrier FDMA (SC-FDMA) networks, and so on. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a RAT such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband-CDMA (W-CDMA) and Low Chip Rate (LCR). cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a RAT such as Global System for Mobile Communications (GSM). An OFDMA network may implement a RAT such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, Flash-OFDM®, etc. UTRA, E-UTRA, and GSM are part of Universal Mobile Telecommunication System (UMTS). Long Term Evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). These documents are publicly available.
FIG. 2 illustrates an example small cell base station with co-located radio components.
The small cell base station 200 may correspond, for example, to one of the small cell base stations 110B, 110C illustrated in FIG. 1. In this example, the small cell base station 200 is configured to provide a Wireless Local Area Network (WLAN) air interface (e.g., in accordance with an IEEE 802.11x protocol) in addition to a cellular air interface (e.g., in accordance with an LTE protocol). For illustration purposes, the small cell base station 200 is shown as including an 802.11x radio component/module (e.g., transceiver) 202 co-located with an LTE radio component/module (e.g., transceiver) 204.
As used herein, the term co-located (e.g., radios, base stations, transceivers, etc.) may include in accordance with various aspects, one or more of, for example: components that are in the same housing; components that are hosted by the same processor; components that are within a defined distance of one another; and/or components that are connected via an interface (e.g., an Ethernet switch) where the interface meets the latency requirements of any required inter-component communication (e.g., messaging).
Returning to FIG. 2, the Wi-Fi radio 202 and the LTE radio 204 may perform monitoring of one or more channels (e.g., on a corresponding carrier frequency) to perform various corresponding operating channel or environment measurements (e.g., CQI, RSSI, RSRP, or other RLM measurements) using corresponding Network/Neighbor Listen (NL) modules 206 and 208, respectively, or any other suitable component(s).
The small cell base station 200 may communicate with one or more user devices via the Wi-Fi radio 202 and the LTE radio 204, illustrated as an STA 250 and a UE 260, respectively. Similar to the Wi-Fi radio 202 and the LTE radio 204, the STA 250 includes a corresponding NL module 252 and the UE 260 includes a corresponding NL module 262 for performing various operating channel or environment measurements, either independently or under the direction of the Wi-Fi radio 202 and the LTE radio 204, respectively. In this regard, the measurements may be retained at the STA 250 and/or the UE 260, or reported to the Wi-Fi radio 202 and the LTE radio 204, respectively, with or without any pre-processing being performed by the STA 250 or the UE 260.
While FIG. 2 shows a single STA 250 and a single UE 260 for illustration purposes, it will be appreciated that the small cell base station 200 can communicate with multiple STAs and/or UEs. Additionally, while FIG. 2 illustrates one type of user device communicating with the small cell base station 200 via the Wi-Fi radio 202 (i.e., the STA 250) and another type of user device communicating with the small cell base station 200 via the LTE radio 204 (i.e., the UE 260), it will be appreciated that a single user device (e.g., a smartphone) may be capable of communicating with the small cell base station 200 via both the Wi-Fi radio 202 and the LTE radio 204, either simultaneously or at different times.
As is further illustrated in FIG. 2, the small cell base station 200 may also include a network interface 210, which may include various components for interfacing with corresponding network entities (e.g., Self-Organizing Network (SON) nodes), such as a component for interfacing with a Wi-Fi SON 212 and/or a component for interfacing with an LTE SON 214. The small cell base station 200 may also include a host 220, which may include one or more general purpose controllers or processors 222 and memory 224 configured to store related data and/or instructions. The host 220 may perform processing in accordance with the appropriate RAT(s) used for communication (e.g., via a Wi-Fi protocol stack 226 and/or an LTE protocol stack 228), as well as other functions for the small cell base station 200. In particular, the host 220 may further include a RAT interface 230 (e.g., a bus or the like) that enables the radios 202 and 204 to communicate with one another via various message exchanges.
FIG. 3 depicts an exemplary method for channel selection 300. In an example, an objective is to strike a balance between selecting the cleanest channel (i.e., the channel with the least interference) and keeping access points operating on the same channel as often as possible, in order to reduce the cost of inter-frequency measurement. Thus, a distributed solution is provided, with minimum operations, administration, and maintenance device (OAM) interactions. Accordingly, an access point receives an input from the OAM device and runs a channel selection algorithm (e.g., an algorithm described herein) autonomously. A list of candidate channels can be received from the OAM device. The list may or may not be the same for each individual access point. In an example, candidate channels might have non-LTE interference, but no LTE macrocells or picoscells, to ensure received signal strength indication (RSSI) is a good indicator of the channel “cleanness.” If at least one of LTE macro cells or pico cells are present, then the LTE macro cells' contribution to the RSSI, and the pico cells' contribution to the RSSI, should be removed from the RSSI. For the n-th channel, n=1, . . . , N, the access point performs these operations.
In block 305, the device (e.g., a neighborhood small cell) boots up. Channel selection is performed, and can also be performed with NLM. The channel selection can use at least one of the following inputs: (1) RSSI measurements associated with a candidate channel; or (2) Network Listen results on a candidate channel, such as from a neighboring access point that is discovered. In addition to using the RSSI measurement for channel selection, the Network Listen process can obtain channel usage distribution of other access points surrounding the current access point, and use the channel usage distribution of the other access points to weigh the RSSI measurement.
In block 310, parameters are initialized, and a list of candidate channels (N) is received (e.g., from the OAM device). Other optional parameters can also be received from the OAM device (e.g., a priority of a specific channel).
In block 315, it is determined if channel selection is triggered. For example, an OAM device can trigger channel selection. If channel selection is not triggered, then block 315 repeats. If channel selection is triggered, then the method for channel selection 300 proceeds to block 320.
In block 320, an RSSI measurement is made on a candidate channel. Multiple measurements can be taken per candidate channel. The measurements can be separated in time to overcome channel coherence. For example, an accurate RSSI measurement of a specific channel n is obtained (RSSI_n). This can be done, for example, by performing a total of M instantaneous RSSI measurements: RSSI_n(k), k=1, . . . , M, separated by time duration T so that RSSI_n(k) and RSSI_n(k+1) can be considered independent. Then RSSI_n=Σ_k=1 ^MRSSI_n(k)/M in the linear domain. The RSSI measurement can be either wideband or narrowband, and the measurement and post-processing can remove contributions from the other neighboring access points, if any are present in the initial RSSI measurement.
In block 325, network listening (NL) techniques are performed on candidate channels from the neighboring access points. For example, NL is performed and an access point on channel n is acquired. The number of neighboring access points acquired is denoted as K_n. Other methods can be used to determine K_n. For example, for LTE access points, at least one of an RSSI or an RSRP threshold can be enforced during the acquisition process so that only “strong” neighboring access points are counted as K_n.
In block 330, channel selection is performed. For example, the access point applies a utility function ƒ(RSSI, K) on the n-th channel, n=1, . . . , N, and denotes the resulting utility as ƒ_n=ƒ(RSSI_n, K_n. The choice of utility function ƒ(RSSI, K) can be any function that satisfies the following constraints:
ƒ(RSSI, K) is a decreasing function of RSSI, i.e., if RSSI₁>RSSI₂, then ƒ(RSSI₁, K)<ƒ(RSSI₁, K), ∀k. This implies that channels with higher interference (hence higher RSSI) will have lower utility.
ƒ(RSSI, K) is an increasing function of K, i.e., if K₁>K₂, then ƒ(RSSI, K₁)>ƒ(RSSI, K₂), ∀RSSI. This implies that channels with more access points will have higher utility.
An exemplary utility function ƒ(RSSI, K) is: ƒ(RSSI, K)=−(RSSI−K×A), where RSSI and A are both in dB value, and Δ is a configurable parameter. The access point compares ƒ(RSSI, K) for all of the N channels and selects the channel that has the highest utility as the channel selection outcome.
In this example, the total number of acquired neighboring small cells K_nis used as an input to the channel selection algorithm. More refined NL results can also be fed into the channel selection algorithm for variants of the proposed channel selection algorithm. For example, in addition to K, one can also feed the measurement result for each cell, for example, (RSRP₁, RSRP₂, . . . , RSRP_K).
Following block 330, the method for channel selection 300 proceeds to block 315.
The blocks in FIG. 3 can be performed by respective modules for performing the respective blocks, where the respective modules are coupled together to form an apparatus.
FIGS. 4A-C depict an exemplary method for channel selection 400. Once selected, the self-optimizing network informs the OAM device of the chosen communication channel. The OAM device can inform a stack of the chosen communication channel and the stack can enforce selecting the chosen communication channel.
The method for channel selection 400 begins at start 402.
At block 404, it is determined if NLM is enabled. If no, then proceed to block 406. If yes, proceed to block 412. The NLM process can provide detailed NL information for each of the candidate communication channels, such as at least one of physical cell identity, reference signal received power, reference signal received quality, or a received signal strength indicator (RSSI). RSSI can be measured for any given sub-channel in the candidate channels.
At block 406, a first available channel is selected a list provided by an OAM device as the chosen communication channel.
At block 408, optionally, at least one of (1) transmit data is transmitted via the chosen communication channel or (2) receive data is received via the chosen communication channel.
At block 410, the method for channel selection 400 ends.
At block 412, input information is received. The input information can include at least one of a candidate channel list ({ƒ₁, ƒ_N} [EARFCN]), a respective RSSI measurement for the candidate channels in the candidate channel list (RSSI_n[dBm]: n=1, N), a number of how many neighbors are discovered on a candidate channels in the candidate channel list (K_n: n=1, N), a preferred channel(s) for operation (ƒ_prefer[EARFCN]), and/or an OAM channel list. The list of channel selection candidates can be different from a list of neighbor discovery candidates.
At block 414, a candidate channel list is arranged to reflect a priority of each communication channel in the candidate channel list. Optionally, a preferred channel is set as a higher priority communication channel in the candidate channel list. The priority indicates a respective bias for each candidate channel.
At block 416, a candidate communication channel in the candidate channel list is evaluated in order by priority, where the evaluating is based on at least one of (1) a transmission characteristic of the candidate channel or (2) received data from at least one access point.
At block 418, when the selecting is based on the transmission characteristic, go to FIG. 4B.
At block 420, when the selecting is based on the received data, go to FIG. 4C.
At block 422, a respective transmission characteristic of the candidate channel is measured to create a respective transmission characteristic measurement of the candidate channel. Optionally, the respective transmission characteristic is a received signal strength indication of the candidate channel.
At block 424, it is determined if the respective transmission characteristic measurement is within a range. Optionally, the range is less than a received signal strength indication operational threshold. If the transmission characteristic of the candidate channel is in range, proceed to block 426. If the transmission characteristic of the candidate channel is not in range, proceed to block 432.
At block 426, the candidate communication channel is selected as the chosen communication channel.
At block 428, optionally, at least one of (1) transmit data is transmitted via the chosen communication channel or (2) receive data is received via the chosen communication channel.
At block 430, the method for channel selection 400 ends.
At block 432, it is determined if a number of neighboring cells on the candidate channel is greater than a threshold number of neighboring cells. If yes, proceed to block 426. If no, proceed to block 434.
At block 434, it is determined if all of the communication channels in the candidate channel list has been processed. If yes, proceed to block 436. If no, proceed to block 438.
At block 436, the candidate channel with the lowest RSSI is chosen as the chosen communication channel. Proceed to block 428.
At block 438, repeat block 422 using a subsequent candidate communication channel from the candidate channel list. Proceed to block 422.
At block 440, when the selecting is based on the received data, channel use data indicating that the at least one access point is capable of using the candidate communication channel is received from at least the one access point. Proceed to block 442.
At block 442, it is determined if the at least one access point is capable of using the candidate communication channel. If yes, proceed to block 444. If no, proceed to block 450.
At block 444, the candidate communication channel is selected as the chosen communication channel. Proceed to block 446.
At block 446, optionally, at least one of (1) transmit data is transmitted via the chosen communication channel or (2) receive data is received via the chosen communication channel. Proceed to block 448.
At block 448, either (1) at least a portion of the method for channel selection 400 is repeated using a subsequent candidate communication channel from the candidate channel list by returning to 440, or (2) proceed to block 448 and end.
The blocks in FIG. 4 can be performed by respective modules for performing the respective blocks, where the respective modules are coupled together to form an apparatus.
FIG. 5 illustrates several sample components (represented by corresponding blocks) that may be incorporated into an apparatus 502, an apparatus 504, and an apparatus 506 (corresponding to, for example, a user device, a base station, and a network entity, respectively) to support the operations as taught herein. It will be appreciated that these components may be implemented in different types of apparatuses in different implementations (e.g., in an ASIC, in a SoC, etc.). The illustrated components may also be incorporated into other apparatuses in a communication system. For example, other apparatuses in a system may include components similar to those described to provide similar functionality. Also, a given apparatus may contain one or more of the components. For example, an apparatus may include multiple transceiver components that enable the apparatus to operate on multiple carriers and/or communicate via different technologies.
The apparatus 502 and the apparatus 504 each include at least one wireless communication device (represented by the communication devices 508 and 514 (and the communication device 520 if the apparatus 504 is a relay)) for communicating with other nodes via at least one designated RAT. Each communication device 508 includes at least one transmitter (represented by the transmitter 510) for transmitting and encoding signals (e.g., messages, indications, information, and so on) and at least one receiver (represented by the receiver 512) for receiving and decoding signals (e.g., messages, indications, information, pilots, and so on). Similarly, each communication device 514 includes at least one transmitter (represented by the transmitter 516) for transmitting signals (e.g., messages, indications, information, pilots, and so on) and at least one receiver (represented by the receiver 518) for receiving signals (e.g., messages, indications, information, and so on). If the apparatus 504 is a relay station, each communication device 520 may include at least one transmitter (represented by the transmitter 522) for transmitting signals (e.g., messages, indications, information, pilots, and so on) and at least one receiver (represented by the receiver 524) for receiving signals (e.g., messages, indications, information, and so on).
A transmitter and a receiver may comprise an integrated device (e.g., embodied as a transmitter circuit and a receiver circuit of a single communication device) in some implementations, may comprise a separate transmitter device and a separate receiver device in some implementations, or may be embodied in other ways in other implementations. A wireless communication device (e.g., one of multiple wireless communication devices) of the apparatus 504 may also comprise a Network Listen Module (NLM) or the like for performing various measurements.
The apparatus 506 (and the apparatus 504 if it is not a relay station) includes at least one communication device (represented by the communication device 526 and, optionally, 520) for communicating with other nodes. For example, the communication device 526 may comprise a network interface that is configured to communicate with one or more network entities via a wire-based or wireless backhaul. In some aspects, the communication device 526 may be implemented as a transceiver configured to support wire-based or wireless signal communication. This communication may involve, for example, sending and receiving: messages, parameters, or other types of information. Accordingly, in the example of FIG. 5, the communication device 526 is shown as comprising a transmitter 528 and a receiver 530. Similarly, if the apparatus 504 is not a relay station, the communication device 520 may comprise a network interface that is configured to communicate with one or more network entities via a wire-based or wireless backhaul. As with the communication device 526, the communication device 520 is shown as comprising a transmitter 522 and a receiver 524.
The apparatuses 502, 504, and 506 also include other components that may be used in conjunction with the operations as taught herein. The apparatus 502 includes a processing system 532 for providing functionality relating to, for example, user device operations to support as taught herein and for providing other processing functionality. The apparatus 504 includes a processing system 534 for providing functionality relating to, for example, base station operations to support as taught herein and for providing other processing functionality. The apparatus 506 includes a processing system 536 for providing functionality relating to, for example, network operations to support as taught herein and for providing other processing functionality. The apparatuses 502, 504, and 506 include memory components 538, 540, and 542 (e.g., each including a memory device), respectively, for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, and so on). In addition, the apparatuses 502, 504, and 506 include user interface devices 544, 546, and 548, respectively, for providing indications (e.g., audible and/or visual indications) to a user and/or for receiving user input (e.g., upon user actuation of a sensing device such a keypad, a touch screen, a microphone, and so on).
For convenience, the apparatuses 502, 504, and/or 506 are shown in FIG. 5 as including various components that may be configured according to the various examples described herein. It will be appreciated, however, that the illustrated blocks may have different functionality in different designs.
The components of FIG. 5 may be implemented in various ways. In some implementations, the components of FIG. 5 may be implemented in one or more circuits such as, for example, one or more processors and/or one or more ASICs (which may include one or more processors). Here, each circuit may use and/or incorporate at least one memory component for storing information or executable code used by the circuit to provide this functionality. For example, some or all of the functionality represented by blocks 508, 532, 538, and 544 may be implemented by processor and memory component(s) of the apparatus 502 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Similarly, some or all of the functionality represented by blocks 514, 520, 534, 540, and 546 may be implemented by processor and memory component(s) of the apparatus 504 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Also, some or all of the functionality represented by blocks 526, 536, 542, and 548 may be implemented by processor and memory component(s) of the apparatus 506 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components).
FIG. 6 depicts an example base station apparatus 600 represented as a series of interrelated functional modules. A module for measuring a transmission characteristic for each channel in a plurality of channels to create a transmission characteristic measurement for each channel 602 may correspond at least in some aspects to, for example, a communication device as discussed herein. A module for receiving, from at least one neighboring access point, data indicating the neighboring access point uses a channel in the plurality of channels 604 may correspond at least in some aspects to, for example, a processing system as discussed herein. A module for calculating a utility value for each channel in the plurality of channels by weighting, based on the number of the neighboring access points using each channel in the plurality of channels, the transmission characteristic measurement for each channel in the plurality of channels 606 may correspond at least in some aspects to, for example, a processing system in conjunction with a communication device as discussed herein. A module for choosing the channel having the highest utility value or the lowest utility value as the communication channel to use for the transmitting 608 may correspond at least in some aspects to, for example, a processing system in conjunction with a communication device as discussed herein.
FIG. 7 illustrates an example user device apparatus 700 represented as a series of interrelated functional modules. A module for measuring a transmission characteristic for each channel in a plurality of channels to create a transmission characteristic measurement for each channel 702 may correspond at least in some aspects to, for example, a communication device as discussed herein. A module for receiving, from at least one neighboring access point, data indicating the neighboring access point uses a channel in the plurality of channels 704 may correspond at least in some aspects to, for example, a processing system as discussed herein. A module for calculating a utility value for each channel in the plurality of channels by weighting, based on the number of the neighboring access points using each channel in the plurality of channels, the transmission characteristic measurement for each channel in the plurality of channels 706 may correspond at least in some aspects to, for example, a processing system in conjunction with a communication device as discussed herein. A module for choosing the channel having the highest utility value or the lowest utility value as the communication channel to use for the transmitting 708 may correspond at least in some aspects to, for example, a processing system in conjunction with a communication device as discussed herein.
The functionality of the modules of FIGS. 6-7 may be implemented in various ways consistent with the teachings herein. In some designs, the functionality of these modules may be implemented as one or more electrical components. In some designs, the functionality of these blocks may be implemented as a processing system including one or more processor components. In some designs, the functionality of these modules may be implemented using, for example, at least a portion of one or more integrated circuits (e.g., an ASIC). As discussed herein, an integrated circuit may include a processor, software, other related components, or some combination thereof. Thus, the functionality of different modules may be implemented, for example, as different subsets of an integrated circuit, as different subsets of a set of software modules, or a combination thereof. Also, it will be appreciated that a given subset (e.g., of an integrated circuit and/or of a set of software modules) may provide at least a portion of the functionality for more than one module.
In addition, the components and functions represented by FIGS. 6-7, as well as other components and functions described herein, may be implemented using any suitable means. Such means also may be implemented, at least in part, using corresponding structure as taught herein. For example, the components described above in conjunction with the “module for” components of FIGS. 6-7 also may correspond to similarly designated “means for” functionality. Thus, in some aspects one or more of such means may be implemented using one or more of processor components, integrated circuits, or other suitable structure as taught herein.
FIG. 8 illustrates an example communication system environment in which the teachings and structures herein may be may be incorporated. The wireless communication system 800, which will be described at least in part as an LTE network for illustration purposes, includes a number of eNBs 810 and other network entities. Each of the eNBs 810 provides communication coverage for a particular geographic area, such as macro cell or small cell coverage areas.
In the illustrated example, the eNBs 810A, 810B, and 810C are macro cell eNBs for the macro cells 802A, 802B, and 802C, respectively. The macro cells 802A, 802B, and 802C may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. The eNB 810X is a particular small cell eNB referred to as a pico cell eNB for the pico cell 802X. The pico cell 802X may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. The eNBs 810Y and 810Z are particular small cells referred to as femto cell eNBs for the femto cells 802Y and 802Z, respectively. The femto cells 802Y and 802Z may cover a relatively small geographic area (e.g., a home) and may allow unrestricted access by UEs (e.g., when operated in an open access mode) or restricted access by UEs having association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG), UEs for users in the home, etc.), as discussed in more detail below.
The wireless network 800 also includes a relay station 810R. A relay station is a station that receives a transmission of data and/or other information from an upstream station (e.g., an eNB or a UE) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE or an eNB). A relay station may also be a UE that relays transmissions for other UEs (e.g., a mobile hotspot). In the example shown in FIG. 8, the relay station 810R communicates with the eNB 810A and a UE 820R in order to facilitate communication between the eNB 810A and the UE 820R. A relay station may also be referred to as a relay eNB, a relay, etc.
The wireless network 800 is a heterogeneous network in that it includes eNBs of different types, including macro eNBs, pico eNBs, femto eNBs, relays, etc. As discussed in more detail above, these different types of eNBs may have different transmit power levels, different coverage areas, and different impacts on interference in the wireless network 800. For example, macro eNBs may have a relatively high transmit power level whereas pico eNBs, femto eNBs, and relays may have a lower transmit power level (e.g., by a relative margin, such as a 10 dBm difference or more).
Returning to FIG. 8, the wireless network 800 may support synchronous or asynchronous operation. For synchronous operation, the eNBs may have similar frame timing, and transmissions from different eNBs may be approximately aligned in time. For asynchronous operation, the eNBs may have different frame timing, and transmissions from different eNBs may not be aligned in time. Unless otherwise noted, the techniques described herein may be used for both synchronous and asynchronous operation.
A network controller 830 may couple to a set of eNBs and provide coordination and control for these eNBs. The network controller 830 may communicate with the eNBs 810 via a backhaul. The eNBs 810 may also communicate with one another, e.g., directly or indirectly via a wireless or wireline backhaul.
As shown, the UEs 820 may be dispersed throughout the wireless network 800, and each UE may be stationary or mobile, corresponding to, for example, a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or other mobile entities. In FIG. 8, a solid line with double arrows indicates desired transmissions between a UE and a serving eNB, which is an eNB designated to serve the UE on the downlink and/or uplink. A dashed line with double arrows indicates potentially interfering transmissions between a UE and an eNB. For example, UE 820Y may be in proximity to femto eNBs 810Y, 810Z. Uplink transmissions from UE 820Y may interfere with femto eNBs 810Y, 810Z. Uplink transmissions from UE 820Y may jam femto eNBs 810Y, 810Z and degrade the quality of reception of other uplink signals to femto eNBs 810Y, 810Z.
Small cell eNBs such as the pico cell eNB 810X and femto eNBs 810Y, 810Z may be configured to support different types of access modes. For example, in an open access mode, a small cell eNB may allow any UE to obtain any type of service via the small cell. In a restricted (or closed) access mode, a small cell may only allow authorized UEs to obtain service via the small cell. For example, a small cell eNB may only allow UEs (e.g., so called home UEs) belonging to a certain subscriber group (e.g., a CSG) to obtain service via the small cell. In a hybrid access mode, alien UEs (e.g., non-home UEs, non-CSG UEs) may be given limited access to the small cell. For example, a macro UE that does not belong to a small cell's CSG may be allowed to access the small cell only if sufficient resources are available for all home UEs currently being served by the small cell.
By way of example, femto eNB 810Y may be an open-access femto eNB with no restricted associations to UEs. The femto eNB 810Z may be a higher transmission power eNB initially deployed to provide coverage to an area. Femto eNB 810Z may be deployed to cover a large service area. Meanwhile, femto eNB 810Y may be a lower transmission power eNB deployed later than femto eNB 810Z to provide coverage for a hotspot area (e.g., a sports arena or stadium) for loading traffic from either or both eNB 810C, eNB 810Z.
In view of the descriptions and explanations above, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
Accordingly, it will be appreciated, for example, that an apparatus or any component of an apparatus may be configured to (or made operable to or adapted to) provide functionality as taught herein. This may be achieved, for example: by manufacturing (e.g., fabricating) the apparatus or component so that it will provide the functionality; by programming the apparatus or component so that it will provide the functionality; or through the use of some other suitable implementation technique. As one example, an integrated circuit may be fabricated to provide the requisite functionality. As another example, an integrated circuit may be fabricated to support the requisite functionality and then configured (e.g., via programming) to provide the requisite functionality. As yet another example, a processor circuit may execute code to provide the requisite functionality.
Moreover, the methods, sequences, and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor (e.g., cache memory).
Accordingly, it will also be appreciated, for example, that certain aspects of the disclosure can include a computer-readable medium embodying a method for selecting a communication channel to use.
While the foregoing disclosure shows various illustrative aspects, it should be noted that various changes and modifications may be made to the illustrated examples without departing from the scope defined by the appended claims. The present disclosure is not intended to be limited to the specifically illustrated examples alone. For example, unless otherwise noted, the functions, steps, and/or actions of the method claims in accordance with the aspects of the disclosure described herein need not be performed in any particular order. Furthermore, although certain aspects may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

Claims

What is claimed is:

1. A method for selecting a communication channel to use, comprising:

measuring a transmission characteristic for each channel in a plurality of channels to create a transmission characteristic measurement for each channel;

receiving, from at least one neighboring access point, data indicating the neighboring access point uses a channel in the plurality of channels;

calculating a utility value for each channel in the plurality of channels by weighting, based on the number of the neighboring access points using each channel in the plurality of channels, the transmission characteristic measurement for each channel in the plurality of channels; and

choosing the channel having the highest utility value or the lowest utility value as the communication channel to use for the transmitting.

2. The method of claim 1, wherein the measured transmission characteristic is at least one of a received signal strength indication, a reference signal received power, or a combination thereof.

3. The method of claim 1, wherein the measuring is performed multiple times for the at least one channel in the plurality of channels, and further comprising at least one of determining a median of the measured respective transmission characteristics for the at least one channel in the plurality of channels, determining a percentile of the measured respective transmission characteristics for the at least one channel in the plurality of channels, averaging, over time, the measured respective transmission characteristics for the at least one channel in the plurality of channels, or a combination thereof.

4. The method of claim 1, wherein the calculating uses the following equation to determine the utility value (U_n) for a channel (n) in the plurality of channels:

U _n=−(M _n −K _n*Δ)

where:

M_n=the transmission characteristic measurement for the channel,

K_n=the number of neighboring access points using the channel, and

Δ=an amount to bias the transmission characteristic measurement for each neighboring access point using the channel.

5. An apparatus configured to selecting a communication channel to use, comprising a processor configured to:

measure a transmission characteristic for each channel in a plurality of channels to create a transmission characteristic measurement for each channel;

receive, from at least one neighboring access point, data indicating the neighboring access point uses a channel in the plurality of channels;

calculate a utility value for each channel in the plurality of channels by weighting, based on the number of the neighboring access points using each channel in the plurality of channels, the transmission characteristic measurement for each channel in the plurality of channels; and

choose the channel having the highest utility value or the lowest utility value as the communication channel to use for the transmitting.

6. The apparatus of claim 5, wherein the measured transmission characteristic is at least one of a received signal strength indication, a reference signal received power, or a combination thereof.

7. The apparatus of claim 5, wherein the processor is configured to perform the measuring multiple times for the at least one channel in the plurality of channels, and the processor is further configured to at least one of determine a median of the measured respective transmission characteristics for the at least one channel in the plurality of channels, determine a percentile of the measured respective transmission characteristics for the at least one channel in the plurality of channels, average, over time, the measured respective transmission characteristics for the at least one channel in the plurality of channels, or a combination thereof.

8. The apparatus of claim 5, wherein the processor is configured to use the following equation to determine the utility value (U_n) for a channel (n) in the plurality of channels:

U _n=−(M _n −K _n*Δ)

where:

M_n=the transmission characteristic measurement for the channel,

K_n=the number of neighboring access points using the channel, and

9. The apparatus of claim 5, wherein at least a part of the apparatus is integrated on a semiconductor die.

10. The apparatus of claim 5, further comprising at least one of a mobile device, an access point, a communications device, a personal digital assistant (PDA), a fixed location data unit, a computer with which the processor is integrated, or a combination thereof.

11. A method for choosing a communication channel, comprising:

arranging a candidate channel list to reflect a priority of each communication channel in the candidate channel list;

evaluating, in order by priority, a candidate communication channel in the candidate channel list, wherein the evaluating is based on at least one of a transmission characteristic of the candidate channel, received data from at least one access point, or a combination thereof; and

selecting, based on results of the evaluating, the candidate communication channel as the chosen communication channel.

12. The method of claim 11, wherein the selecting is based on the transmission characteristic and the evaluating further comprises:

measuring a respective transmission characteristic of the candidate channel to create a respective transmission characteristic measurement of the candidate channel;

determining if the respective transmission characteristic measurement is within a range; and

selecting, if the respective transmission characteristic measurement is within the range, the candidate communication channel as the chosen communication channel.

13. The method of claim 12, further comprising:

stopping, after selecting the chosen communication channel, the measuring the respective transmission characteristic.

14. The method of claim 12, wherein the respective transmission characteristic is a received signal strength indication of the candidate channel.

15. The method of claim 13, wherein the range is less than a received signal strength indication operational threshold.

16. The method of claim 15, wherein the evaluating further includes performing the following when the respective transmission characteristic measurement is not within the range:

checking if a number of neighboring cells on the candidate channel is greater than a threshold number of neighboring cells;

selecting, if the number of neighboring cells on the candidate channel is greater than the threshold number of neighboring cells, the candidate channel as the chosen communication channel; and

repeating the evaluating using a subsequent candidate channel in the channel candidate list, if the number of neighboring cells on the candidate channel is not greater than the threshold number of neighboring cells.

17. The method of claim 11, further comprising selecting the candidate channel having the lowest received signal strength indication as the chosen communication channel when all channels in the candidate channel list have been evaluated, and none of the candidate channels have been selected as the chosen communication channel.

18. The method of claim 11, wherein the selecting is based on the received data and the evaluating further comprises:

receiving, from at least the one access point, channel use data indicating that the at least one access point is capable of using the candidate communication channel;

if the at least one access point is capable of using the candidate communication channel, then the candidate communication channel is selected as the chosen communication channel; and

at least one access point is not capable of using the candidate communication channel, then the evaluating is repeated using a subsequent candidate channel in the channel candidate list.

19. The method of claim 11, further comprising:

repeating the evaluating for a subsequent candidate channel in the channel candidate list until the chosen communication channel is selected.

20. The method of claim 11, further comprising:

determining if a preferred channel is in the candidate channel list; and

wherein the arranging includes setting the preferred channel as a higher priority communication channel in the candidate channel list, when the preferred channel is in the candidate channel list.

21. The method of claim 11, further comprising at least one of transmitting data. receiving data, or a combination thereof, via the chosen communication channel.

22. An apparatus configured to choose a communication channel, comprising a special-purpose processor configured to:

arrange a candidate channel list to reflect a priority of each communication channel in the candidate channel list;

evaluate, in order by priority, a candidate communication channel in the candidate channel list, wherein the evaluating is based on at least one of a transmission characteristic of the candidate channel, received data from at least one access point, or a combination thereof; and

select, based on results of the evaluating, the candidate communication channel as the chosen communication channel.

23. The apparatus of claim 22, wherein the processor is configured to select based on the transmission characteristic and is configured to:

measure a respective transmission characteristic of the candidate channel to create a respective transmission characteristic measurement of the candidate channel;

determine if the respective transmission characteristic measurement is within a range; and

select, if the respective transmission characteristic measurement is within the range, the candidate communication channel as the chosen communication channel.

24. The apparatus of claim 23, wherein the processor is further configured to:

stop, after selecting the chosen communication channel, the measuring the respective transmission characteristic.

25. The apparatus of claim 23, wherein the respective transmission characteristic is a received signal strength indication of the candidate channel.

26. The apparatus of claim 25, wherein the range is less than a received signal strength indication operational threshold.

27. The apparatus of claim 26, wherein the processor is configured to performing the following when the respective transmission characteristic measurement is not within the range:

28. The apparatus of claim 22, wherein the processor is configured to select the candidate channel having the lowest received signal strength indication as the chosen communication channel when all channels in the candidate channel list have been evaluated, and none of the candidate channels have been selected as the chosen communication channel.

29. The apparatus of claim 22, wherein the processor is configured to select based on the received data and is configured to:

receive, from at least the one access point, channel use data indicating that the at least one access point is capable of using the candidate communication channel;

select, when the at least one access point is capable of using the candidate communication channel, the candidate communication channel as the chosen communication channel; and

repeat the evaluating using a subsequent candidate channel in the channel candidate list when the at least one access point is not capable of using the candidate communication channel.

30. The apparatus of claim 22, further comprising at least one of a mobile device, an access point, a communications device, a personal digital assistant (PDA), a fixed location data unit, a computer, or a combination thereof, with which the processor is integrated.