WO2009022294A2

WO2009022294A2 - Power saving for uplink scheduling grant signaling and decoding

Info

Publication number: WO2009022294A2
Application number: PCT/IB2008/053228
Authority: WO
Inventors: Chun Yan Gao (Adele); Da Qing Wang
Original assignee: Nokia Corporation; Nokia, Inc.
Priority date: 2007-08-14
Filing date: 2008-08-12
Publication date: 2009-02-19
Also published as: WO2009022294A3

Abstract

Each of a plurality of user equipments UEs is associated with one downlink radio resource within a duty cycle. Scheduling grant control entities, each granting only one uplink resource within the duty cycle are sent to each of the UEs in their associated DL resources. For the case where within one duty cycle there is more than one scheduling grant control entity for an individual UE, then a first scheduling grant control entity for that UE is sent in the UE's associated downlink resource all remaining scheduling grant control entities for that UE are chained to the first scheduling grant control entity. Chaining can indicate whether or not there is a subsequent scheduling grant control entity for that same UE within the duty cycle and/or within the same downlink resource.

Description

POWER SAVING FOR UPLINK SCHEDULING GRANT SIGNALING AND DECODING

TECHNICAL FIELD:

[0001] The teachings herein relate generally to wireless networks that allocate uplink and downlink resources to mobile/user equipment, particularly how those allocations are signaled and how the mobile/user equipment finds and decodes the signaling.

BACKGROUND:

[0002] The following abbreviations and terms are herewith defined:

3GPP third generation partnership project

CCFI control channel format indicator (alternatively CatO)

DL downlink

Node B base station, or evolved node B of an LTE system

E-UTRAN evolved UTRAN

FDD: frequency division duplex

LTE long term evolution of 3GPP, (also E-UTRAN or 3.9G)

MME mobility management entity

Node B base station or similar network access node

OFDM orthogonal frequency division multiplex

PDCCH packet data control channel

RNC radio network controller

TDD time division duplex

TTI transmission time interval

UE user equipment (e.g., mobile equipment/station)

UL uplink

UTRAN UMTS terrestrial radio access network

[0003] 3GPP is standardizing the long-term evolution (LTE) of the radio-access technology which aims to achieve reduced latency, higher user data rates, improved system capacity and coverage, and reduced cost for the operator. The current understanding of LTE relevant to these teachings may be seen at 3GPP TR 25.814 (v7.1.0, 2006-09) entitled PHYSICAL LAYER ASPECTS OF EVOLVED UTRA and herein incorporated by reference. Both FDD and TDD are considered in LTE for different operation modes. Due to their difference in frame structure and duplex mode, some designs for FDD and TDD can be different (see section 6.2 et seq. of TR 25.814). As stated at section 6.2.1 , "E-UTRA, when operating in TDD mode-of-operation, may face additional interference scenarios, compared to when operating in FDD mode of operation. More specifically, direct UE-to-UE and BS-to-BS interference may occur both within one carrier and between neighbour carriers." As LTE develops it is clear that there are to be some differences as between the FDD and TDD modes of operation.

[0005] Some general principles of scheduling in E-UTRAN are recited at section

7.2.1 of TR 25.814. The Node B scheduler dynamically controls which time/frequency resources are allocated to a certain user at a given time. Downlink control signaling informs UE(s) what resources and respective transmission formats have been allocated. The scheduler can instantaneously choose the best multiplexing strategy from the available methods; e.g. frequency localized or frequency distributed transmission. The flexibility in selecting resource blocks and multiplexing UEs will influence the available scheduling performance. Scheduling is tightly integrated with link adaptation and hybrid automatic repeat request HARQ.

[0006] In FDD, it has been agreed that there are at most 3 OFDM symbols in each

TT! that are reserved for control signaling. Consider for this description that a TTl is one subframe. Those 3 OFDM symbols are to include DL and UL scheduling grants as well as CCFI/CatO information that gives the format of the control channel. The CCFI/CatO is length 2 bits and indicates how many OFDM symbols are used for control.

[0007] There has been some interest in developing LTE as to how exactly to map the UL resources that are allocated to a UE to the scheduling grant sent on a DL control channel (the PDCCH in LTE) that grants to the UE those UL resources. Because the control channel is a common channel to which multiple UE listen for their respective grants, much control signaling overhead may be saved by having some mapping from the scheduling grant itself to the radio resources being granted to the UE. Some proposals advance an implicit mapping and others advance explicit signaling of the mapping. For example and in the TDD operation mode, the UL scheduling grant for the / th UL sub-frame can be sent in a certain DL sub-frame based on some pre-defined implicit TTi indication as seen at Document R1-071868, DOWNLINK CONTROL SIGNALLING FOR E-UTRA TDD, 3GPP TSG RANi LTE TDD AdHoc, Beijing, China, April 17-20, 2007, by Motorola [Exhibit A of the priority provisional application], or can be sent in any DL sub-frame with- an explicit TTI indication in the scheduling grant as seen at Document R1-071882, TTI INDICATION FOR LTE TDD, 3GPP TSG RAN1 LTE TDD AdHoc, Beijing, China, April 17-20, 2007, by CATT [Exhibit B of the priority provisional application]. [0008] In considering how best to address the mapping issue, the inventors have found another more subtle problem these other solutions appear to have overlooked. Specifically, they overlook that the UE does not know in which of the DL subframes to look for its UL scheduling grant. Whether the mapping is intrinsic or extrinsic, the UE must look in each and every DL control subframe that might have a scheduling grant directed to that UE and see if one is actually there. Only then does the mapping solution come into play, but by that time the UE may have decoded multiple control channel DL subframes in which it was not scheduled at all.

[0009] Whether the TT! indication should be implicit or explicit, the uplink scheduling grants are usually transmitted in multiple downlink sub-frames per TDD frame, as shown in Figure 1. Since before detection the UE does not know where is the UL scheduling grant for itself then it requires the detection for control signaling in multiple DL sub-frames though the UL scheduling grant for this UE may be sent in one DL sub-frame. Additionally, it is generally assumed in LTE that blind detection will b e used to decode the uplink scheduling grant information, so when there is no scheduling grant information transmitted for a particular UE, that UE must to go through a!! the coding schemes for blind detection. From the UE's perspective this is quite wasteful of its power supply and processing capacity. But previous considerations for mapping scheduling grants sent on the common DL control channel to the UL radio resource being granted focus on how to balance flexibility in the network's grants of the radio resources with control signaling overhead.

[0010] This is best illustrated by an example with reference to Figure 1. Assume that a particular UE is granted by the network (e.g., by a Node B of the network) to transmit uplink packet data in UL subframe #6 and UL subframe #8, for which the uplink scheduling grant control information are transmitted in downlink sub frame DL #0 and DL #2 according to DL/UL mapping in Figure 1. For simplicity the mapping in Figure 1 is assumed to be one- to-one and implicit: a grant in the ith DL subframe is for radio resources in the corresponding (i+4)th UL subframe, and the network and the UE's know this implicit mapping without signaling it on the PDCCH with the scheduling grants (though different Node Bs may signal it over a broadcast channel with, for example system information). Other more complex mapping solutions are available, but the manner in which the UL resources being granted are mapped to the DL subframe in which the scheduling grant for those resources is received is not seen to resolve the problem that this simple example will illustrate. So a grant received in subframe #0 is for UL transmissions in subframe 6; a grant received in subframe #1 is for UL transmissions in subframe #7, and so forth. For the particular UE in this example, it will decode all downlink sub frames DL #0, DL #1, DL#2, DL#3 to get uplink scheduling grant information (in this example it is assumed that both the network and the UE know in advance that scheduling grants are not to be sent in subframes DL #4 or DL #5). But by the assumptions above, subframes DL#1 and DL #3 do not carry uplink scheduling grant information for this particular UE, so the power used for decoding and blind detection in DL#1 and DL #3 are wasted.

[0011] What is needed in the art is a way to balance the network's need for scheduling flexibility and efficient control signaling against the UE's limited power supply and processing power.

Summary:

[0012] In accordance with one exemplary embodiment of the invention is a method that includes storing a pre-determined association of each of a plurality of user equipments in a cell to one downlink radio resource, and sending scheduling grant control entities to each of the plurality of the user equipments in the downlink radio resource to which they are respectively associated, wherein each scheduling grant control entity grants only one uplink radio resource.

[0013] In accordance with another exemplary embodiment of the invention is a memory embodying a computer program executable by a processor to perform actions directed to scheduling user equipments for radio resources. In this embodiment the actions include storing a pre-determined association of each of a plurality of user equipments in a cell to one downlink radio resource, and sending scheduling grant control entities to each of the plurality of the user equipments in the downlink radio resource to which they are respectively associated, wherein each scheduling grant control entity grants only one uplink radio resource.

[0014] In accordance with still another exemplary embodiment of the invention is an apparatus that includes memory means (e.g., a computer readable memory) and sending means (e.g., a transmitter). The memory means is for storing a pre-determined association of each of a plurality of user equipments in a cell to one downlink radio resource. The sending means is for sending scheduling grant control entities to each of the plurality of the user equipments in the downlink radio resource to which they are respectively associated. Each scheduling grant control entity grants only one uplink radio resource. In other embodiments the apparatus includes processing means (e.g., a digital processor) and receiving means (e.g., a receiver). [0015] In accordance with yet another exemplary embodiment of the invention is a method that includes storing a pre-determined association of a user equipment to one downlink radio resource of a duty cycle, and in each duty cycle, searching for a first scheduling grant control entity for the user equipment only in the downlink radio resource with which the user equipment is associated. Each of the first scheduling grant control entity and any other scheduling grant control entities grant one uplink radio resource.

[0016] In accordance with another exemplary embodiment of the invention is a memory embodying a computer program executable by a processor to perform actions directed to finding where in a duty cycle to search for a scheduling grant control entity. In this embodiment the actions include storing a pre-determined association of a user equipment to one downlink radio resource of a duty cycle, and in each duty cycle, searching for a first scheduling grant control entity for the user equipment only in the downlink radio resource with which the user equipment is associated. Each of the first scheduling grant control entity and any other scheduling grant control entities grant one uplink radio resource.

[0017] In accordance with a further exemplary embodiment of the invention is an apparatus that includes memory means (e.g., a computer readable memory) and processing means (e.g., a digital processor). The memory means is for storing a pre-determined association of a user equipment to one downlink radio resource of a duty cycle. The processing means is for searching in each duty cycle for a first scheduling grant control entity for the user equipment only in the downlink radio resource with which the user equipment is associated. Each of the first scheduling grant control entity and any other scheduling grant control entities grant one uplink radio resource. Other embodiments include sending means (e.g., a transmitter) and receiving means (e.g., a receiver).

BRIEF DESCRIPTION OF THE DRAWINGS:

[0018] The foregoing and other aspects of these teachings are made more evident in the following Detailed Description when read in conjunction with the attached Drawing Figures.

[0019] Figure 1 is a schematic diagram of a prior art TDD frame structure where a scheduling grant received in an ith DL subframe is for UL resources in a corresponding (i+4)th UL subframe. [0020] Figure 2 is similar to Figure 1 but illustrating four groupings of UEs according to which DL subframe they may be granted UL resources, according to an aspect of the invention.

[0021] Figure 3 is a block diagram of three scheduling grant control entities and illustrating one approach to how they might be 'chained' to enable greater network flexibility in scheduling multiple UL grants to one UE within a single DL subframe.

[0022] Figure 4 shows a simplified block diagram of various electronic devices that are suitable for use in practicing the exemplary embodiments of this invention.

[0023] Figure 5 is a flow diagram showing a method according to a first and a second aspect of the invention.

DETAILED DESCRIPTION:

[0024] While the description below is in the context of LTE, the breadth of the invention is not limited only to that wireless protocol and may be practiced, for example, in any network in which UL scheduling grants are sent to UEs dynamically in DLs that map to the UL resources being granted. For example, GSM (global system for mobile communications) or UMTS (universal mobile telecommunications system) may be adapted for such a granting protocol. More generic terms are introduced to avoid the implication that the use of terms specific to LTE in the examples below limit the invention to LTE: a DL radio resource represents what in LTE is a DL subframe and is a discrete unit of DL radio resources in which scheduling grants are sent from the network to the UEs in a cell; and a UL radio resource represents the unit of UL radio resources being granted, which in LTE is the UL subframe mapped to the DL subframe bearing the grant. It is only exemplary that the below description uses terms such as subframe that are commonly associated with LTE.

[0025] Embodiments of this invention relate to DL control signaling and are feasible regardless of the specific mapping of DL subframe in which a scheduling grant is received to the UL subframe being granted. According to an embodiment of the invention, the network sends all uplink scheduling grants for a particular UE in one downlink subframe per duty cycle. This differs from the prior art where a UE is granted more than only a single UL scheduling grant within one duty cycle. As above, the prior art would map each of the granted UL subframes to a specific DL subframe within the duty cycle in which it was granted. Where there is more than one UL grant for a particular UE according to this embodiment, all of those scheduling grants are sent in the same DL subframe.

[0026] According to an embodiment of the invention and from the UE's perspective, the UE decodes only one DL subframe per duty cycle for scheduling information. Of course, if the UE is to receive other non-scheduling information on another DL subframe in the same duty cycle it may still do so. But the UE knowing in advance in which DL subframe to look for its scheduling grants eliminates the problem detailed above with reference to Figure 1 where the UE decodes multiple (all) DL subframes to find its scheduling grant and much of that decoding is to no avail. Therefore the UE saves power by not decoding those DL subframes in which the network has not sent it a scheduling grant.

[0027] How to implement this in a manner that leaves sufficient flexibility for the network is described by way of example. Instead of mapping the uplink radio resources to a downlink control subframe in which they are granted as in the prior art noted above, consider for this description the concept of a 'scheduling grant control entity', which maps to one uplink radio resource. This concept is employed to address the various approaches proposed by which the mapping to the UL resource/subframe is actually done: explicit, implicit or hybrid. Whether that scheduling grant control entity is an explicitly signaled bit field, or an implicit mapping from a position of a UE identifier, or some other way of mapping to the granted UL subframe, it is understood herein to represent a grant to a UE for one uplink sub-frame.

[0028] Now, if multiple uplink sub-frames are to be allocated for a UE, there will be multiple uplink scheduling grant control entities transmitted in downlink, and one scheduling grant control entity is mapping to an uplink sub-frame. To give maximum flexibility to the network's scheduling function, the prior art would generally result in these control entities being placed in the DL subframe corresponding to the UL subframe they granted, so as to save on control signaling overhead. According to an embodiment of this invention, these control entities for one particular UE may be chained or linked to one another in a single DL subframe.

[0029] In the subframe in which the UE knows to expect its scheduling grants, the

UE first blindly decodes the scheduling grant control entities and examines them to see if any are grants for that particular UE. When it finds the first scheduling grant control entity granting a UL radio resource to itself, the UE finds information in that first scheduling grant control entity indicating whether additional scheduling grant control entities within that same DL subframe are chained to it. If yes, then the UE continues to decode subsequent scheduling grant control entities in that DL subframe. Each additional scheduling grant control entity also indicates whether there is a further scheduling grant control entities within that same DL subframe chained to it, and each control entity chained to another is a grant for the same UE. If no, for the first or any subsequent scheduling grant control entities, then the UE knows that there are no further grants in that DL subframe and may discontinue decoding further in search of a grant. In this manner, the UE engages in blind detection only in the DL subframe in which it knows a priori to look for a scheduling grant control entity directed toward itself, and only until it finds a first one of them. All further control entities in the DL subframe are either chained to the first, or if not chained then the UE knows it need not decode them. This saves baseband power for decoding and blind detection, and allows a side flexibility to the network to allocate resources to the various UEs as they need them; some get no resources while others may get multiple UL grants within the same duty cycle.

[0030] A particular implementation is illustrated at Figure 2, which shows one duty cycle. The duty cycle generically represents the interval at which the DL-UL scheduling cycle, from the network perspective, is repeated. In LTE the duty cycle is a frame (currently, one 10 msec radio frame=two 5 msec frames each having 7 or 9 traffic timeslots or subframes). As an initial matter, the UEs in the cell (of the serving Node B) are assigned by a higher layer such as the Node B, RNC/MME, or other network node to a particular subframe. This assignment informs the UEs individually which DL subframe in which their scheduling grant control entities are to be found when they are scheduled for a UL resource. So the assignment or association is pre-defined.

[0031] As two examples, this assignment/association may be given to the UE upon entry into the cell, or it may be a pre-defined association based on the (permanent) universal identifier number uniquely associated with each UE or based on a temporary identifier given to the UE upon entry into the cell, for example. As an example of an association based on an identifier, one selected digit (e.g., first or last) of the identifier or a logical operation on a portion of the identifier may be associated with a particular DL subframe #), and that association is known a priori by both the network and the UE. A formula giving an operation that the UEs are to perform to determine to which DL subframe they are associated may be broadcast in a cell's system information, or it can be explicitly signaled at other times, apart from entry into the cell, from the network to the UE. As can be appreciated, exactly how to make the association between particular UEs and particular DL subframes, and how to make that association known to the UEs, can be implemented in numerous ways and is not limited to those examples above, [0032] Note that in Figure 2 there are only four DL subframes in which the network can place the various scheduling grant control entities: subframes DL #0, DL#1 , DL #2 and DL #3. Though the division of the frame in LTE is flexible and allows the network to dynamically vary the DL/UL split as traffic may dictate, one will see that typically there will be more UEs in the cell than DL subframes in which the Node B may put its scheduling grant control entities. Therefore, the UEs in a cell are grouped, so that at any given time in a cell the association of UE to DL subframe will result in multiple UEs assigned to a single DL subframe.

[0033] Assume for Figure 2 that there are twelve UEs in the cell under control of a single Node B (including any relay stations under control of the Node B). According to the a priori association of UE to DL subframe, in this example the twelve UEs are dispersed among four groups: UE #s 1 , 2 and 3 are in a first group 202 and assigned subframe DL#0; UE #s 4 and 5 are in a second group 204 and assigned subframe DL#1 ; UE #s 6, 7 and 8 are in a third group 206 and assigned subframe DL#2; and UE #s 9, 10, 11 and 12 are in a fourth group 208 and assigned subframe DL#3.

[0034] While the network knows the grouping, it is not necessary that any individual

UE knows the group it is in (it need only know the DL subframe assigned to it) or the other UEs in its group. Each UE need only know the DL subframe to which it is assigned, and so in the example of Figure 2, UE #5 knows it is assigned to DL subframe #1 and need not decode any of the other DL subframes in search of its scheduling grants, UE11 knows it is assigned to DL subframe #3 and need not decode any of the other DL subframes in search of its scheduling grants, and so forth. Since the duty cycle repeats every 10 msec in LTE, and in any analogous scheduling system it will repeat quite frequently, the power savings to the individual UEs accumulate quite quickly as compared to the UEs doing blind detection in every DL subframe in search of their scheduling grant(s).

[0035] Figure 3 illustrates one embodiment of chaining the scheduling grant control entities together. Despite the additional control signaling in this example, the concept of chaining is useful to give the network wider flexibility in how it schedules traffic in its cell. When a particular UE requires high data rate transmission in upiink, or when the UE is located at cell edge, the UE will require multiple uplink sub-frames for uplink transmission. Spreading these across multiple duty cycles (e.g., one UL subframe per duty cycle per UE) is very limiting, so according to the chaining concept multiple uplink scheduling grant control entities, each granting one UL subframe to one UE, are transmitted in one downlink sub- frame. Figure 3 illustrates three such scheduling grant control entities 302, 304, 306 within one DL subframe. According to this embodiment, a bit 308 is added at the end of each control entity 302, 304, 306 to indicate whether there is subsequent control entity for that same UE within this same DL subframe. If this bit is set to '1' as in control entity reference number 302, it means there is a subsequent control entity (reference number 304) for this UE in this DL subframe, and UE should continue the decoding process in this DL subframe. If this bit is set to '0' as with control entity 306, it means there is no subsequent control entity for this UE in this DL subframe, and the UE can stop the decoding process in this DL subframe. Arbitrarily, term this added bit 308 a 'chaining bit'. As can be appreciate, this chaining bit can be placed anywhere within the scheduling grant control entity that is convenient, not just the last bit position. Further, the designations for "1" and "0" may be reversed from the example given above.

[0036] So in this embodiment the control entities 320, 304, 306 dedicated for a UE are chained together or not as indicated by the chaining bit 308 in each of those entities, and these control entities are put in one downlink sub-frame. The scheduled UE then only needs to decode the pre-defined DL subframe with which it is associated/assigned, and it can receive all its uplink scheduling grant control information in that single DL subframe. In which downlink sub-frame shall these control entities be put, the specific association of UE to DL subframe, is decided and informed to the UE by high layer signaling, as noted above by several examples.

[0037] When the first control entity for a particular UE is successfully decoded by blind detection, the transmission format (e.g., the chaining bit) for this first control entity can be applied to decode subsequent control entities, and they in turn can be decoded without blind detection also. This decreases the times that the UE engages in blind detection and saves power for the UE in two respects: the UE needs only decode in a pre-defined downlink subframe associated with that UE, and the times in which the UE engages in blind detection, even in that pre-determined DL subframe, are reduced. This is because once the UE decodes the first scheduling grant control entity that grants a UL resource to that decoding UE (through blind detection), if there are other control entities chained to the first one the coding rate used for decoding the first control entity can be applied to those subsequent chained control entities, and they can be decoded without blind detection.

[0038] Some variations to the above implementations are within the scope of this disclosure. In a first alternative, the chain of control entities may continue to another DL subframe immediately subsequent to the pre-determined DL subframe with which the UE is associated for scheduling purposes. This gives the Node B a bit wider flexibility in scheduling a particularly demanding UE for additional UL resources in a same duty cycle. In some embodiments the UE will have to engage in blind detection during that immediately subsequent DL subframe else the Node B will be restricted to the same coding rate across different DL subframes in which it places the scheduling grant control entities, but this is seen to be a minimal additional demand and not often required, as typically a single UE will not need such extensive UL grants in one duty cycle.

[0039] In a second alternative, the chaining bit indicates only whether or not that there is a subsequent scheduling grant control entity within the duty cycle, and that subsequent scheduling grant control entity may be immediately following the one to which it is chained, it may be in the next subsequent DL subframe, or it may be in a non-adjacent DL subframe. This allows the Node B even wider flexibility, at the cost of a UE being granted multiple UL resources in a duty cycle having to decode more DL subframes and control entities which may not apply to that UE. Additionally, unless the network is restricted to maintain a same coding rate across those subsequent DL subframes, this additional decoding by the UE will entail blind detection.

[0040] Reference is now made to Figure 4 for illustrating a simplified block diagram of various electronic devices that are suitable for use in practicing the exemplary embodiments of this invention as detailed above. In Figure 4 a wireless network 9 is adapted for communication between a UE 10 and a Node B 12 (e-Node B). The network 9 may include a gateway GW/serving mobility entity MME/radio network controller RNC 14 or other radio controller function known by various terms in different wireless communication systems. The UE 10 includes a data processor (DP) 10A, a memory (MEM) 10B that stores a program (PROG) 10C, and a suitable radio frequency (RF) transceiver 10D coupled to one or more antennas 10E (one shown) for bidirectional wireless communications over one or more wireless links 20 with the Node B 12.

[0041] The Node B 12 also includes a DP 12A, a MEM 12B, that stores a PROG 12C, and a suitable RF transceiver 12D coupled to one or more antennas 12E. The Node B 12 may be coupled via a data path 30 (e.g., lub or S1 interface) to the serving or other GW/MME/RNC 14. The GW/MME/RNC 14 includes a DP 14A, a MEM 14B that stores a PROG 14C, and a suitable modem and/or transceiver (not shown) for communication with the Node B 12 over the lub link 30.

[0042] Also within the node B 12 is a scheduler 12F that schedule the various UEs under its control for the various UL and DL radio resources or subframes. Once scheduled, the Node B sends messages to the UEs with the scheduling grants (typically multiplexing grants for multiple UEs in one message). These grants are sent over the particular channels noted with the specific embodiments detailed above. Generally, the Node B 12 of an LTE system is fairly autonomous in its scheduling and need not coordinate with the GW/MME 14 excepting during handover of one of its UEs to another Node B.

[0043] At least one of the PROGs 1 OC, 12C and 14C is assumed to include program instructions that, when executed by the associated DP, enable the electronic device to operate in accordance with the exemplary embodiments of this invention, as detailed above. Inherent in the DPs 1OA, 12A, and 214A is a clock to enable synchronism among the various apparatus for transmissions and receptions within the appropriate time intervals and slots required, as the scheduling grants and the granted resources are time dependent.

[0044] The PROGs 1OC, 12C, 14C may be embodied in software, firmware and/or hardware, as is appropriate. In general, the exemplary embodiments of this invention may be implemented by computer software stored in the MEM 1OB and executable by the DP 1QA of the UE 10 and similar for the other MEM 12B and DP 12A of the Node B 12, or by hardware, or by a combination of software and/or firmware and hardware in any or all of the devices shown.

[0045] In general, the various embodiments of the UE 10 can include, but are not limited to, mobile stations, cellular telephones, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, as well as portable units or terminals that incorporate combinations of such functions.

[0046] The MEMs 10B, 12B and 14B may be of any type suitable to the iocai technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The DPs 10A, 12A and 14A may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples.

[0047] Figure 5 is a process flow diagram representing process steps according to an embodiment of the invention. At block 501 is stored in a computer readable memory an association of UE to DL radio resources, which in LTE the radio resources might be a subframes of the PDCCH. For the UE, it need store only its association with a DL subframe, whereas a network node such as a Node B would store at block 501 a pre-determined association of each of a plurality of UEs in a cell to one downlink subframe. As detailed above, this will typically involve a grouping of the UEs, different groups associated with one DL subframe. At block 502, the UE decodes scheduling grant control entities in the DL subframe with which it is associated, and does not decode other control entities in others of the DL subframes with which it is not associated in the memory. At block 504, the network node sends scheduling grant control entities to individual ones of the plurality of UEs in the DL subframes with which they are respectively associated in the memory.

[0048] According to an embodiment of the invention then is a memory embodying a computer program, and a method, and an apparatus, each of which operate to store a predetermined association of each of a plurality of UEs in a cell to one downlink radio resource/subframe, and to send scheduling grant control entities to each of the plurality of the UEs in the downlink radio resource/subframe to which they are respectively associated, each scheduling grant control entity granting one uplink radio resource/subframe. The association remains for the duration that each particular ones of the plurality of UEs remain in the cell, and all of the associated DL radio resources/subframes and all of the granted UL radio resources/subframes are within one time-bounded duty cycie. In an embodiment, all of the scheduling grant control entities for each individual one of the plurality of UEs is sent in the DL radio resource/subframe to which the respective individual one of the plurality of UEs is associated. In a further embodiment, each of the scheduling grant control entities comprises chaining information indicating whether or not there is a subsequent scheduling grant control entity for that same UE within the duty cycle, and in still another embodiment the chaining information indicates whether or not there is a subsequent scheduling grant control entity for that same UE within the same DL radio resource/subframe. in an embodiment, the association is signaled to the UEs, on a broadcast channel as a logical operation to perform on an identifier or part thereof, or individually upon establishment of individual ones of the UEs in the cell. A network node such as a Node B of a LTE network may practice this aspect of the invention.

[0049] According to another aspect of the invention is a memory embodying a computer program, and a method, and an apparatus, each of which operate to store a pre-determined association of a UE to one downlink radio resource/subfranne, and to receive and decode scheduling grant control entities in the downlink radio resource/subframe to which the UE is associated and to not decode other of the DL radio resources/subframes to which it is not associated, each scheduling grant control entity granting one uplink radio resource/subframe. The association remains for the duration that the UE remains in the cell, in an embodiment, the UE receives and decodes all of the scheduling grant control entities for it in the DL radio resource/subframe to which it is associated. In a further embodiment, the UE determines from chaining information in a first scheduling grant control entity whether or not there is a subsequent scheduling grant control entity for the UE within the duty cycle. If yes, then the UE decodes a subsequent scheduling grant control entity within the duty cycle, possibly using a coding rate determined from decoding the first scheduling grant control entity. If no, then the UE does not decode further scheduling grant control entities within the associated DL radio resource/subframe. In any case, once the apparatus decodes a scheduling grant control entity in its associated DL radio resource/subframe, it transmits on the UL radio resource/subframe that is mapped to the DL radio resource/subframe. In an embodiment, the apparatus receives the association from the network on a broadcast channel as a logical operation to perform on its identifier or part thereof, or upon the apparatus becoming established in the cell. A UE in a LTE network may practice this aspect of the invention.

[0050] For the aspects of this invention related to sending the scheduling grant control entity to the UEs, embodiments of this invention may be implemented by computer software executable by a data processor of the Node B 12, such as the processor 12A shown, or by hardware, or by a combination of software and hardware. For the aspects of this invention related to receiving the scheduling grant control entity and then using the granted resources (e.g., tuning to the granted resource at the given time and receiving or sending on it), embodiments of this invention may be implemented by computer software executable by a data processor of the UE 10, such as the processor 10A shown, or by hardware, or by a combination of software and hardware. Further in this regard it should be noted that the various logical step descriptions above may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, biocks and functions.

[0051] In general, the various embodiments may be implemented in hardware or special purpose circuits, software (computer readable instructions embodied on a computer readable medium), logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0052] Embodiments of the inventions may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

[0053] Programs, such as those provided by Synopsys, Inc. of Mountain View, California and Cadence Design, of San Jose, California automatically route conductors and locate components on a semiconductor chip using well established rules of design as well as libraries of pre-stored design modules. Once the design for a semiconductor circuit has been completed, the resultant design, in a standardized electronic format (e.g., Opus, GDSII, or the like) may be transmitted to a semiconductor fabrication facility or "fab" for fabrication.

[0054] Various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications of the teachings of this invention will still fall within the scope of the non-limiting embodiments of this invention.

[0055] Although described in the context of particular embodiments, it will be apparent to those skilled in the art that a number of modifications and various changes to these teachings may occur. Thus, while the invention has been particularly shown and described with respect to one or more embodiments thereof, it wiii be understood by those skilled in the art that certain modifications or changes may be made therein without departing from the scope of the invention as set forth above, or from the scope of the ensuing claims.

Claims

CLAIMS:We claim:

1. A method comprising: storing a pre-determined association of each of a plurality of user equipments in a cell to one downlink radio resource; and sending scheduling grant control entities to each of the plurality of the user equipments in the downlink radio resource to which they are respectively associated, wherein each scheduling grant control entity grants only one uplink radio resource.

2. The method of claim 1 , wherein all of the downlink radio resources associated with the plurality of user equipments and all of the granted uplink radio resources are within one time-bounded duty cycle.

3. The method of claim 1 , wherein the case where within one duty cycle there is more than one scheduling grant control entity for any individual user equipment of the plurality of user equipments, sending comprises sending at least a first one of the scheduling grant control entities for that individual user equipment in the downiink radio resource with which the individual user equipment is associated and chaining all remaining scheduling grant control entities for the individual user equipment to the first scheduling grant control entity.

4. The method of claim 3, wherein all of the scheduling grant control entities for the individual user equipment is sent in the downlink radio resource with which the individual user equipment is associated.

5. The method of claim 3, wherein each of the scheduling grant control entities comprises chaining information indicating whether or not there is a subsequent scheduling grant control entity for a same user equipment within the duty cycle.

6. The method of claim 5, wherein the chaining information indicates whether or not there is a subsequent scheduling grant control entity for the same user equipment within the same downlink radio resource.

7. The method of claim 1 , further comprising signaling to the plurality of user equipments an indication of a logical operation that operates on a user equipment identifier or part thereof by which to determine the pre-determined association.

8. A memory embodying a computer program executable by a processor to perform actions directed to scheduling user equipments for radio resources, the actions comprising: storing a pre-determined association of each of a plurality of user equipments in a cell to one downlink radio resource; and sending scheduling grant control entities to each of the plurality of the user equipments in the downlink radio resource to which they are respectively associated, wherein each scheduling grant control entity grants only one uplink radio resource.

9. An apparatus comprising: memory means for storing a pre-determined association of each of a plurality of user equipments in a cell to one downlink radio resource; and sending means for sending scheduling grant control entities to each of the plurality of the user equipments in the downlink radio resource to which they are respectively associated, wherein each scheduling grant control entity grants only one uplink radio resource.

10. The apparatus of claim 9, wherein all of the downlink radio resources associated with the plurality of user equipments and all of the granted uplink radio resources are within one time-bounded duty cycle.

11. The apparatus of claim 9, wherein the case where within one duty cycle there is more than one scheduling grant control entity for any individual user equipment of the plurality of user equipments, the sending means is for sending at least a first one of the scheduling grant control entities for that individual user equipment in the downlink radio resource with which the individual user equipment is associated and for chaining all remaining scheduling grant control entities for the individual user equipment to the first scheduling grant control entity.

12. The apparatus of claim 11 , wherein the sending means is for sending all of the scheduling grant control entities for the individual user equipment in the downlink radio resource with which the individual user equipment is associated.

13. The apparatus of claim 11 , wherein each of the scheduling grant control entities comprises chaining information indicating whether or not there is a subsequent scheduling grant control entity for a same user equipment within the duty cycle.

14. The apparatus of claim 13, wherein the chaining information indicates whether or not there is a subsequent scheduling grant control entity for the same user equipment within the same downlink radio resource.

15. The apparatus of claim 9, wherein the sending means is further for signaling to the plurality of user equipments an indication of a logical operation that operates on a user equipment identifier or part thereof by which to determine the pre-determined association.

16. A method comprising: storing a pre-determined association of a user equipment to one downlink radio resource of a duty cycle; and in each duty cycle, searching for a first scheduling grant control entity for the user equipment only in the downlink radio resource with which the user equipment is associated, wherein each of the first scheduling grant control entity and any other scheduling grant control entities grant one uplink radio resource.

17. The method of claim 16, further comprising: finding the first scheduling grant control entity in the downlink radio resource with which the user equipment is associated; decoding the first scheduling grant control entity, and only decoding any other scheduling grant control entity in the duty cycle if said other scheduling grant control entity is chained to the first scheduling grant control entity; and transmitting on each uplink radio resource that is granted by one of the decoded scheduling grant control entities.

18. The method of claim 17, wherein decoding comprises reading chaining information from the first scheduling grant control entity and only decoding a subsequent scheduling grant control entity in the duty cycle if the chaining information of the first scheduling grant control entity indicates that there is a subsequent scheduling grant control entity for the user equipment.

19. The method of claim 16, wherein for the case where the chaining information of the first scheduling grant control entity indicates that there is a subsequent scheduling grant control entity for the user equipment and the subsequent scheduling grant control entity is in the downlink radio resource associate with the user equipment: decoding the first scheduling grant control entity comprises blind detecting the first scheduling grant control entity; and thereafter using at least a coding rate determined from decoding the first scheduling grant control entity to decode the subsequent scheduling grant control entity that is chained to the first scheduling grant control entity.

20. The method of claim 16, further comprising retaining the association in a local memory of the user equipment only for the duration that the user equipment remains in the cell.

21. The method of claim 16, wherein for any duty cycle, all of the scheduling grant control entities for the user equipment are in the downlink radio resource with which the user equipment is associated.

22. The method of claim 16, further comprising, prior to the storing, receiving from a network an indication of a logical operation that operates on a user equipment identifier or part thereof and using the logical operation to determine the association.

23. A memory embodying a computer program executable by a processor to perform actions directed to finding where in a duty cycle to search for a scheduling grant control entity, the actions comprising: storing a pre-determined association of a user equipment to one downlink radio resource of a duty cycle; and in each duty cycle, searching for a first scheduling grant control entity for the user equipment only in the downlink radio resource with which the user equipment is associated, wherein each of the first scheduling grant control entity and any other scheduling grant control entities grant one uplink radio resource.

24. An apparatus comprising: memory means for storing a pre-determined association of a user equipment to one downlink radio resource of a duty cycle; and processing means for searching in each duty cycle for a first scheduling grant control entity for the user equipment only in the downlink radio resource with which the user equipment is associated, wherein each of the first scheduling grant control entity and any other scheduling grant control entities grant one uplink radio resource.

25. The apparatus of claim 24, wherein for the case where the processing means finds the first scheduling grant control entity in the downlink radio resource with which the user equipment is associated, the processing means is further for decoding the first scheduling grant control entity, and only attempts to decode any other scheduling grant control entity in the duty cycle if said other scheduling grant control entity is chained to the first scheduling grant control entity; the apparatus further comprising transmit means for transmitting on each uplink radio resource that is granted by one of the decoded scheduling grant control entities.

26. The apparatus of claim 25,, wherein the processing means is further for reading chaining information from the first scheduling grant control entity and only decodes a subsequent scheduling grant control entity in the duty cycle if the chaining information of the first scheduling grant control entity indicates that there is a subsequent scheduling grant control entity for the user equipment.

27. The apparatus of claim 24, wherein for the case where the chaining information of the first scheduling grant control entity indicates that there is a subsequent scheduling grant control entity for the user equipment and the subsequent scheduling grant control entity is in the downlink radio resource associate with the user equipment: the processing means is for decoding the first scheduling grant control entity by blind detecting the first scheduling grant control entity; and thereafter the processing means is for using at least a coding rate determined from decoding the first scheduling grant control entity for decoding the subsequent scheduling grant control entity that is chained to the first scheduling grant control entity.

28. The apparatus of claim 24, wherein the processing means and the memory means are for retaining the association in the memory means only for the duration that the apparatus remains in the cell.

29. The apparatus of claim 24, wherein for any duty cycle, all of the scheduling grant control entities for the user equipment are in the downlink radio resource with which the user equipment is associated.

30. The apparatus of claim 24, further comprising receiving means for receiving from a network, prior to the memory means storing the pre-determined association, an indication of a iogicai operation that operates on a user equipment identifier or part thereof and the processing means using the logical operation to determine the pre-determined association.