WO2014088402A1

WO2014088402A1 - A system and method for routing in a network

Info

Publication number: WO2014088402A1
Application number: PCT/MY2013/000224
Authority: WO
Inventors: Nordin Ramli; Hafizal Mohamad; Wai Kean CHONG
Original assignee: Mimos Bhd.
Priority date: 2012-12-06
Filing date: 2013-12-03
Publication date: 2014-06-12
Also published as: MY164492A

Abstract

The present invention generally relates to a system and method for routing in a network, more particularly the present invention relates to a system and method for routing in a wireless mesh network comprising a backhaul network (11), at least a router (12) in communication with the backhaul network (11) for providing data traffic through a distribution network, at least an access point (13) in communication with the router (12) for providing network coverage through at least a channel, and at least a transceiver node (14) provided with a spectrum sensing module (15), in communication with the router (12) for providing network connectivity to at least an end user, and communicates with at least another transceiver node (14) for providing continued network connectivity.

Description

A SYSTEM AND METHOD FOR ROUTING IN A NETWORK

TECHNICAL FIELD

The present invention generally relates to a system and method for routing in a network, more particularly the present invention relates to a system and method for routing in a wireless mesh network.

BACKGROUND OF INVENTION

Wireless communication systems envisages to provide a high-speed, high bandwidth ubiquitous connectivity to end users through a heterogeneous network, which consist technologies such as third and fourth generation mobile cellular network, wireless local area network (WLAN) and emerging broadband wireless technologies such as IEEE802.16.

One of key components in such converged networks is the wireless mesh network (WMN) which can provide significant advantages in deploying low-cost, highly efficient and reconfigurable network over large areas. Although, enhancements have been implemented to provide better performance, problems of primary hidden nodes (PHN) and primary exposed nodes (PEN) are often inevitable. Primary hidden node will cause severe data loss due to the interference, and primary exposed node will cause packet loss and increase transmission delay because sudden appearance of an access point may render a channel unusable and cause route failure. This would require frequency rerouting and contribute to excessive end to end delay.

There are several prior arts divulged system and method for providing method of routing in a wireless network to address the problems above. US patent no. 7616655 B2 discloses a method and system to avoid exposed nodes in wireless mesh network by setting channels, preventing a node from transmitting data using duration comparison, and thereafter updating the node using duration comparison. US patent application publication no. 2008/069034 Al discloses a method and system using inter-node interference data to improve routing of data within a wireless mesh network. The prior art anticipates the problems of interference in a wireless mesh network, and can be related to the primary hidden node and primary expose node problems. US patent application publication no. 2008/159207 Al discloses method and apparatus for cognitive spectrum assignment for mesh networks, wherein the prior art teaches a routing algorithm used in a system to always attempt to ensure that the data takes the fastest route. The prior arts however are deficient in providing a solution to the present problem, as the prior arts do not fundamentally address the issues of hidden nodes and exposed nodes. The present invention, on the other hand, herein asserts to essentially tackle the issues of hidden nodes and exposed nodes.

SUMMARY OF INVENTION

The present invention is targeted at alleviating the aforementioned problems using cognitive radio paradigm that aims at devising spectrum sensing and management techniques, thereby allowing radios to intelligently locate and use frequencies other than those in the designated band.

It is one object of the present invention to provide a system for routing in a network, preferably in a mesh network comprising a backhaul network, at least a router in communication with the backhaul network for providing data traffic through a distribution network, at least an access point in communication with the router for providing network coverage through at least a channel, and at least a transceiver node for providing network connectivity. It is another object of the present invention to provide a system for routing in a network, preferably in a mesh network comprising and at least a transceiver node provided with a spectrum sensing module, in communication with the router for providing network connectivity to at least an end user, and communicates with at least another transceiver node for providing continued network connectivity.

It is yet an object of the present invention to provide a system for routing in a network, preferably in a mesh network comprising the transceiver node incorporated with a management module that collects data activity from the spectrum sensing module and allocate channels for selecting a routing path, and a cognitive module that analyzes channel availability and utilization by comparing input data received from the management module with the existing data stored in the cognitive module.

It is yet another object of the present invention to provide a method for routing in a network, preferably in a mesh network comprises the steps of receiving route request packet at a transceiver node, processing the route request packet for retrieving and checking information of a source node, a destination node and channels, determining whether the transceiver node is the destination node.

It is a further object of the present invention to provide a method for routing in a network, preferably in a mesh network comprising methods for routing in a network when the transceiver node is the destination node, routing in a network when the transceiver node is not the destination node, performing route maintenance, determining a common spectrum opportunity list, a basic list and a superior list.

It is therefore that the present invention targets to improve the end-to-end delay for the data transmission, to improve the awareness of the transceiver node, towards the activities of spectrum transmission of an access point, to reduce interference, and to improve the channel selection when primary transceiver node suddenly comes into activation during data transmission.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1 illustrates the overall system for wireless networking in accordance to the present invention. Figure 2 illustrates the system architecture in a transceiver node in accordance to the present invention.

Figure 3 illustrates the point to point system operation in accordance to the present invention.

Figure 4 illustrates the single channel mesh system operation in accordance to the present invention. Figure 5 illustrates the single channel and multi-channel mesh system operation in accordance to the present invention.

Figure 6 illustrates the flowchart for the operational methods of the system in accordance to the present invention.

Figure 7 illustrates the flowchart for the operational methods of the system in accordance to the present invention.

Figure 8 illustrates the flowchart for the operational methods of the system in accordance to the present invention.

Figure 9 illustrates the flowchart for the operational methods of the system in accordance to the present invention. Figure 10 illustrates the flowchart for the operational methods of the system in accordance to the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Described below are preferred embodiments of the present invention with reference to the accompanying drawings. Each of the following preferred embodiments describes an example not limiting in any aspect. Referring to Figure 1 and Figure 2, the figures illustrate the overall system for wireless networking and the system architecture in a transceiver node (14) in accordance to the present invention, wherein the Figure 1 shows an overview of the architecture between a backhaul network (11), a router (12), at least an access point (13), and pluralities of transceiver node (14), and the Figure 2 shows the architecture within the transceiver node (14). The router (12) is preferably a mesh router.

Ultimately, the system for routing in a network in accordance to the present invention comprising a backhaul network (11), at least a router (12) in communication with the backhaul network (11) for providing data traffic through a distribution network, at least an access point (13) in communication with the router (12) for providing network coverage through at least a channel, and at least a transceiver node (14) provided with a spectrum sensing module (15), in communication with the access point (13) for providing network connectivity to at least an end user, and communicates with at least another transceiver node (14) for providing continued network connectivity.

The transceiver node (14) has three main layers, of which are the physical layer, media access control layer, and a network layer. The physical layer comprising the spectrum sensing module (15), which performs modulation, coding with space time block codes (STBC), channel estimation, requesting packet route via hybrid automatic repeat request (HARQ), and determining indicator activation via channel quality indication (CQI).

The spectrum sensing module (15) is any dedicated sensing antenna or through the same antennas used for data transmission via antenna switching. The sensing mechanism can be carried out using any methods such as energy detection and features detection.

The media access control layer further comprising a management module (31) in a mutual operation with a cognitive module (32) for selecting a routing path and performing route maintenance, whereby the management module (31) collects data activity from the spectrum sensing module (15) and allocate channels for selecting a routing path, and the cognitive module (32) analyzes channel availability and utilization by comparing input data received from the management module (31) with the existing data stored in the cognitive module (32). The cognitive module (32) comprising a common spectrum opportunity list for recording common channels between each consecutive transceiver node (14), a basic list generated from the activation indicator for recording channels which have common value of activation indicator between each consecutive transceiver node (14) in the network, and a superior list generated from the common spectrum opportunity list and the basic list for recording common intersected channels between each of the consecutive transceiver node (14). The aforementioned lists will be updated from time to time based on the access point (13) transmitting data in channels whether they are active or not. The network layer in accordance to the present invention is responsible for transmitting data packets to another transceiver node (14) or destination node through a spectrum aware routing path following the determined routing path from the processes in the media access control layer. Spectrum aware routing as adopted in the present invention selects the routing path based on feedback from cognitive module (32) and performs the route maintenance in the presence of the transceiver node (14) in order to avoid interference.

The present invention teaches an improved system and method to select channel and routing path in cognitive radio mesh network consisting of, as previously mentioned, the management module (31) to collect the spectrum sensing results and allocate the channels based on the instruction from cognitive module (32). The cognitive module (32) then analyzes channel availability and utilization based on input from the management module (31).

Once the transceiver node (14) receives the sensing results about the surrounding transceiver node's (14) channel utilization, channel bandwidth and other related results, the results will be fed to the management module (31). In this module, the condition of all available channels in the existing networks will be updated from time to time based on the associated activity. Once the sensing results are updated, the cognitive module (32) will analyze the results based on updated sensing and the fed sensing results and also the route reply from the destination node. The configuration of channel for each transceiver node (14) may vary with different channel allocation, such as the single channel and also multichannel transmission. Both scenarios will be considered and exemplified for the present invention.

Referring to Figure 3, there is illustrated the point to point system operation in accordance to the present invention in a situation with four channels from four access point (13), namely primary user 1 (PUl), primary user 2 (PU2), primary user 3 (PU3), primary user 4 (PU4) with their listenable channel of channel 1 (CHI), channel 2 (CH2), channel 3 (CH3) and channel 4 (CH4) respectively. However, it should be noted that the number of primary users and channels as presented in the present invention should not limiting in any sense, whereby the system and method as preferred in the present invention can be employed with any number of primary users and channels and any number of nodes. It is shown that the primary user 1 (PUl) and primary user 4 (PU4) are in an "ON" state and they are listening to channel 1 (CHI) and channel 4 (CH4) respectively, thereby able to provide network coverage to any device within the range of these channels. On the contrary, primary user 2 (PU2) and primary user 3 (PU3) are in an "OFF" state, which are shown that they are not listening to their respective listenable channels of channel 2 (CH2) and channel 3 (CH3), and temporarily unable to provide network connection to any device present in the region.

By way of example to elucidate the point to point system operation, there is shown one transceiver node (14) identified as the CR X within the coverage of primary user 1 (PUl) and primary user 2 (PU2) with their listenable channel of channel 1 (CHI) and channel 2 (CH2) respectively, and another transceiver node (14) identified as the CR Y within the coverage of primary user 1 (PUl) and primary user 3 (PU3) with their listenable channel of channel 1 (CHI) and channel 3 (CH3) respectively. The CR X is therefore in a region where coverage of primary user 1 (PUl) and coverage of primary user 2 (PU2) with their respective listenable channel of channel 1 (CHI) and channel 2 (CH2) intersects, and the CR Y is therefore in a region where coverage of primary user 1 (PUl) and coverage of primary user 3 (PU3) with their respective listenable channel of channel 1 (CHI) and channel 3 (CH3) intersects, but however, the primary users or access points of channel 1 (CHI), channel 2 (CH2) and channel 3 (CH 3) are unknown to each other.

In any event where the primary user 2 (PU2) or primary user 3 (PU3) comes into activation by listening to channel 2 (CH2) or channel 3 (CH3) respectively, the CR X or CR Y will face interference if they are using either one of the channels for communication, hence jeopardizing the data connection within channel 2 (CH2) or channel 3 (CH3). This is known in the art as the "hidden node" and "exposed node" problem. As a solution to this problem, the inventors institute a system and method to improve channel selection of the CR X and CR Y when either the channel 2 (CH2) or channel 3 (CH3) comes into activation.

As shown in the figure, there are three tables for executing this solution. Firstly, each transceiver node (14), CR X and CR Y, includes a cognitive module (31) and a management module (32) as earlier described in the foregoing description. The cognitive module (31) checks for spectrum opportunity (SOP) for each transceiver node (14) and records the channels as shown in the Table 1(a), wherein the spectrum opportunity (SOP) for CR X are channel 2 (CH2), channel 3 (CH3), and channel 4 (CH4). Likewise, the spectrum opportunity (SOP) for CR Y are similarly channel 2 (CH2), channel 3 (CH3), and channel 4 (CH4).

Table 1(b) denotes the activation indicator for each corresponding transceiver node (14), CR X and CR Y, within network coverage of the primary users with their respective channels. It is shown that CR X is within the coverage of primary user 1 (PU1) and primary user 2 (PU2) with their respective listenable channels of channel 1 (CHI) and channel 2 (CH2), and CR Y is within the coverage of primary user 1 (PU1) and primary user 3 (PU3) with their respective listenable channel of channel 1 (CHI) and channel 3 (CH3). None of the transceiver node (14) is within the coverage of primary user 4 (PU4) with its listenable channel of channel 4 (CH4).

Table 1(c) denotes the common spectrum opportunity, basic spectrum opportunity, and a superior spectrum opportunity between CR X and CR Y. The first column provides the common spectrum opportunity list (CSOL), subsequently the basic list (BL) and the superior list (SL). The common spectrum opportunity list (CSOL) for both the CR X and CR Y includes channel 2 (CH2), channel 3 (CH3) and channel 4 (CH4), which is compared for identical channels in Table 1(a). The basic list (BL) column indicates the common channels resulting from the activation indicator as shown in Table 1(b), of which in this case are the channel 1 (CHI) and channel 4 (CH4). The basic list (BL) is to overcome "hidden node" and "exposed node" problems. The superior list (SL) then indicates all common channels between the common spectrum opportunity list (CSOL) and the basic list (BL), of which in this case is the channel 4 (CH4). The superior list (SL) is to optimize the routing with best channel selection.

Referring to Figure 4, there is illustrated the single channels mesh system operation in accordance to the present invention in a situation with four channels from four access points, namely primary user 1 (PU1), primary user 2 (PU2), primary user 3 (PU3), primary user 4 (PU4) with their listenable channel of channel 1 (CHI), channel 2 (CH2), channel 3 (CH3) and channel 4 (CH4) respectively. There are pluralities of transceiver node (14) in this scenario, and are categorized into Node a, Node b, Node c, Node d, Node e, Node f, Node g, and Node h.

However, it should be noted that the number of channels as presented in the present invention should not limiting in any sense, whereby the system and method as preferred in the present invention can be employed with any number of channels and any number of nodes.

Each transceiver node (14) is arrayed to form a grid connection between each of the transceiver node (14), and the nodes assigned to each category are shown to be scattered across the grid. It is shown that primary user 1 (PU1) and primary user 2 (PU2) are in an "ON" state and they are listening to channel 1 (CHI) and channel 2 (CH2) respectively, thereby able to provide network coverage to any device within the range of these channels. On the contrary, primary user 3 (PU3) and primary user 4 (PU4) are in an "OFF" state, which shows that they are not listening to their respective listenable channels of channel 3 (CH3) and channel 4 (CH4) and temporarily unable to provide network connection to any device present in the region. The access points are however hidden from each other.

Consequently, Node a is not within any coverage of the primary users, Node b is within the coverage of primary user 3 (PU3), Node c is within the coverage of primary user 1 (PUl), Node d is the within the coverage of primary user 1 (PUl) and primary user 2 (PU2), Node e is within the coverage of primary user 1 (PUl), primary user 2 (PU2) and primary user 4 (PU4), Node f is within the coverage of primary user 2 (PU2), Node g is within the coverage of primary user 2 (PU2) and primary user 4 (PU4), and Node h is within the coverage of primary user 4 (PU4).

Henceforth, Node d is in a region where coverage of primary user 1 (PUl) with listenable channel of channel 1 (CHI) and coverage of primary user 2 (PU2) with listenable channel of channel 2 (CH2) intersects, Node e is in an intersection region of coverage of primary user 1 (PUl) with listenable channel of channel 1 (CHI), coverage of primary user 2 (PU2) with listenable channel of channel 2 (CH2) and coverage of primary user 4 (PU4) with listenable channel of channel 4 (CH4), and Node g is in an intersection region of coverage of primary user 2 (PU2) with listenable channel of channel 2 (CH2) and coverage of primary user 4 (PU4) with listenable channel of channel 4 (CH4).

Ensuing that, tables are shown in the figure to illustrate the process for carrying the method for routing in network as preferred in the present invention. Table 2(a) lists all the available channels for each node, which is also known the spectrum opportunity (SOP) for each node.

Channel 1 (CHI), channel 2 (CH2), channel 3 (CH3) and channel 4 (CH4) are available for Node a since this not within the coverage of any primary users who might be listening to their respective listenable channels as earlier noted. Channel 1 (CHI), channel 2 (CH2), channel 3 (CH3) and channel 4 (CH4) are available to Node b because the primary user 3 (PU3) is not listening to channel 3 (CH3) as it is in an "OFF" state. Likewise, channel 2 (CH2), channel 3 (CH3) and channel 4 (CH4) are available to Node c. Then, channel 3 (CH3) and channel 4 (CH4) are available to Node d. Also, channel 3 (CH3) and channel 4 (CH4) are available to Node e. Channel 1 (CHI), channel 3 (CH3) and channel 4 (CH4) are available to Node f. Also, channel 1 (CHI), channel 3 (CH3) and channel 4 (CH4) Node g. Channel 1 (CHI), channel 2 (CH2), channel 3 (CH3) and channel 4 (CH4) are available to Node h. Table 2(b) denotes the activation indicator for each corresponding transceiver node (14), Node a, Node b, Node c, Node d, Node e, Node f, Node g and Node h., within network coverage of the respective primary users with their respective listenable channels. It is shown that the activation indicator for all channels for Node a having the Boolean value of '0' . Activation indicator for Node b has a Boolean value of Ί ' for channel 3 (CH3) and '0' for other channels. Activation indicator for Node c has a Boolean value of T for channel 1 (CHI) and '0' for other channels.

Activation indicator for Node d has Boolean value of Ί ' for channel 1 (CHI) and channel 2 (CH2) and '0' for other channels. Activation indicator for Node e has Boolean value of ' 1 ' for channel 1 (CHI), channel 2 (CH2) and channel 4 (CH4) and '0' for channel 3 (CH3). Activation indicator for Node f has a Boolean value of T for channel 2 (CH2) and '0' for other channels. Activation indicator for Node g has Boolean value of T for channel 2 (CH2) and channel 4 (CH4) and '0' for other channels. Activation indicator for Node b has a Boolean value of T for channel 4 (CH4) and '0' for other channels.

Table 2(c) denotes the common spectrum opportunity, basic spectrum opportunity, and a superior spectrum opportunity for the possible paths generated in each of the transceiver node (14). The first column provides the common spectrum opportunity list (CSOL), subsequently the basic list (BL) and the superior list (SL). Accordingly, the common spectrum opportunity list (CSOL) for each possible path is obtained from Table 2(a), and the basic list is obtained from the channels having common Boolean value resulting from the activation indicator as shown in Table 2(b), to overcome problems of the "hidden node" and "exposed node". The superior list (SL) then indicates all common channels between the common spectrum opportunity list (CSOL) and the basic list (BL) to optimize the routing with best channel selection. Referring to Figure 5, there is illustrated the single and multi-channels mesh system operation in accordance to the present invention in a situation with three channels from three access points (13), namely primary user 1 (PUl) with its listenable channel of channel 1 (CHI) and channel 2 (CH2) and primary user 2 (PU2) with its listenable channel of channel 3 (CH3). There are pluralities of transceiver node (14) in this scenario, and are categorized into Node a, Node b, Node c, and Node d.

Each transceiver node (14) is arrayed to form a grid connection between each of the transceiver node (14), and the nodes assigned to each category are shown to be scattered across the grid. It is shown that primary user 1 (PUl) is in an "ON" state and it is listening to channel 1 (CHI) and channel 2 (CH2), thereby able to provide network coverage to any device within the range of these channels. On the contrary, primary user 2 (PU2) is in an "OFF" state, which shows that it is not listening to its respective listenable channel of channel 3 (CH3) and temporarily unable to provide network connection to any device present in the region.

Access points for channel 1 (CHI) and channel (CH2) are within the range of each other, and therefore are exposed to one another.

Consequently, Node a is not within any coverage of the primary users, Node b is within the coverage of primary user 1 (PUl), Node c is within the coverage of primary user 1 (PUl) and primary user 2 (PU2), and Node d is within the coverage of primary user 2 (PU2). Henceforth, Node c is in a region where coverage of primary user 1 (PUl) and primary user 2 (PU2) intersects. Ensuing that, tables are shown in the figure to illustrate the process for carrying the method for routing in network as preferred in the present invention. Table 3(a) lists all the available channels for each node, which is also known the spectrum opportunity (SOP) for each node. Channel 1 (CHI), channel 2 (CH2) and channel 3 (CH3) are available for Node a since this not within the coverage of any primary users as earlier noted. Channel 3 is available to Node b. Channel 3 (CH3) is available to Node c, and channel 1 (CHI), channel 2 (CH2) and channel 3 (CH3) are available to Node d.

Table 3(b) denotes the activation indicator for each corresponding transceiver node (14), Node a, Node b, Node c and Node d, within network coverage of the respective primary users with their respective listenable channels. It is shown that the activation indicator for all channels for Node a having the Boolean value of '0' because Node a is not within any coverage. Activation indicator for Node b has Boolean value of T for channel 1 (CHI) and channel 2 (CH2) and '0' for channel 3 (CH3). Activation indicator for Node c has Boolean value of T for all channels, namely channel 1 (CHI), channel 2 (CH2) and channel 3 (CH3). Activation indicator for Node d has a Boolean value of Ί ' for channel 3 (CH3) and '0' for other channels.

Table 3(c) denotes the common spectrum opportunity, basic spectrum opportunity, and a superior spectrum opportunity for the possible paths generated in each of the transceiver node (14). The first column provides the common spectrum opportunity list (CSOL), subsequently the basic list (BL) and the superior list (SL). Accordingly, the common spectrum opportunity list (CSOL) for each possible path is obtained from Table 3(a), and the basic list (BL) is obtained from the channels having common Boolean value resulting from the activation indicator as shown in Table 3(b), to overcome problems of the "hidden node" and "exposed node". The superior list (SL) then indicates all common channels between the common spectrum opportunity list (CSOL) and the basic list (BL) to optimize the routing with best channel selection.

Referring to Figure 6, Figure 7, Figure 8, Figure 9 and Figure 10, the figures illustrate the flowchart for the operational methods as preferred for the system in the present invention. As shown in Figure 6, the flowchart illustrates an overall method as preferred in the present invention, wherein the method comprises the steps of initially receiving route request (RREQ) packet at a transceiver node (14), then, processing the route request (RREQ) packet for retrieving and checking information of a source node, a destination node and channels, and determining whether the transceiver node (14) is the destination node.

If the transceiver node (14) is not the destination node, the method comprises the steps of first comparing received route request (RREQ) packet with route request (RREQ) packet stored in the transceiver node (14), and dropping the route request (RREQ) packet for an existing route request (RREQ) packet.

Then, the system determines a common spectrum opportunity (SOP) between the source node and the transceiver node (14) for a fresh route request (RREQ) packet, subsequently analyzing availability of channels and creating a common spectrum opportunity list (CSOL) by comparing the received common spectrum opportunity with common spectrum opportunity (SOP) data stored in the transceiver node (14), then, determining a basic list (BL) by comparing the Boolean value of the activation indicator between the source node and the transceiver node (14), then, determining a superior list (SL) from common intersected channels between the common spectrum opportunity list (CSOL) and the basic list (BL), and finally transmitting the route request (RREQ) packet to the next transceiver node (14). In other words, the flowchart show that, the transceiver node (14) will drop the route request (RREQ) packet if it does not have the common spectrum opportunity (SOP) with the previous one hop node for data transmission. The transceiver node (14) will only generate basic list (BL) and superior list (SL) if there is channel existing in the common spectrum opportunity list (CSOL) and basic list (BL), respectively. Route decision will be made by destination node once the entire route request (RREQ) packet being received at that node.

If the transceiver node (14) is the destination node, the method comprises the steps of selecting routing path from the source node to the transceiver node (14), and sending route reply (RREP) packet to the source node, and finally transmitting data through the selected routing path and performing route maintenance during data transmission. As shown in Figure 7, the flowchart illustrates the method for determining the common spectrum opportunity list (CSOL), comprises the steps of first retrieving the spectrum opportunities (SOPs) from the route request (RREQ) packet and current transceiver node (14) memory, setting the channel sequence to default channel, determining whether the channel exists in spectrum opportunity (SOP) list of consecutive transceiver node (14) is common, inserting the channel in common spectrum opportunity list (CSOL) if both nodes share the common spectrum opportunity (SOP), sorting the common spectrum opportunity list (CSOL) in ascending order according to the channel usage ratio of at least an access point (13), determining whether the number of channels has maxed, and analyzing the next channel whether the channels are sharing the common spectrum opportunity (SOP) with neighboring transceiver node (14).

The flowchart shows that, the next hop node will find the common spectrum opportunity (SOP) with the transceiver node (14) and listing the respective channels into a list known as common spectrum opportunity list (CSOL). It provides the common available channel for each of the both consecutive transceiver node (14) in order for them to communicate with each other.

As shown in Figure 8, the method for determining the basic list (BL), comprises the steps of first retrieving results from activation indicator from a route request (RREQ) packet and data stored in the transceiver node (14) memory, setting the retrieve channels to default channel in order to determine the common activation indicator, and listing channels having common activation indicator into the basic list (BL), sorting the updated basic list (BL) in ascending order according to the channel usage ratio of at least an access point (13), and determining whether the number of channels has maxed, and updating the current default channel to the next channel.

The flowchart shows that, the next hop node will check for the common result of the activation indicator of the primary user with current transceiver node (14) and listing the respective channels into a list known as basic list (BL). It provides the channel for data transmission which able to avoid primary hidden node and primary exposed node problem. As shown in Figure 9, the method for determining the superior list (SL), comprises the steps of first retrieving the common spectrum opportunity list (CSOL) and basic list (BL) from the memory stored in the transceiver node (14), setting the current channel to default channel, determining whether the default channel is the common channel between the common spectrum opportunity list (CSOL) and the basic list (BL), updating thereof for an existing common channel between the common spectrum opportunity list (CSOL) and the basic list (BL), sorting the updated superior list (SL) in ascending order according to the channel usage ratio of at least an access point (13), determining whether the number of channels has maxed, and updating the current default channel to the next channel.

The flowchart shows that, the next hop node will list the common channels that exist in both common spectrum opportunity list (CSOL) and the basic list (BL) into a list known as superior list (SL). It provides the best channel for the data transmission. As shown in Figure 10, the method for performing route maintenance, comprises the steps of first retrieving a common spectrum opportunity list (CSOL), a basic list (BL), and a superior list (SL) from the memory of a transceiver node (14), determining whether the transceiver node (14) is the destination node, determining whether the superior list (SL) is empty, determining availability of channels in the superior list (SL) by checking each listed channel through a predetermined sequence, determining whether the basic list (BL) is empty, determining availability of channels in the basic list (BL) by checking each listed channel through a predetermined sequence, determining whether the common spectrum opportunity list (CSOL) is empty, determining availability of channels in the common spectrum opportunity list (CSOL) and moving a default channel to the subsequent channel, occupying the default channel and transmitting data to a subsequent transceiver node (14) and ensuing towards a destination node, and sending route request (RREQ) packet to the subsequent transceiver node (14) if there is no channel available in the common spectrum opportunity list (CSOL). The flowchart shows that, all the secondary users or known as the transceiver node (14) in the present invention will be aware of the activities of the access point (13) or known as the primary user in the present invention for determining a routing path. When the access point (13) suddenly appears or activates by occupying the dedicated channel during data transmission, the transceiver node (14) will switch to the next channel as listed in superior list (SL). If there are no available channels in the superior list (SL), the transceiver node (14) will choose to switch to the available channel that is listed in basic list (BL). On the other hand, if there are no available channels in the basic list (BL), the transceiver node (14) will choose to switch to the available channel that listed in common spectrum opportunity list (CSOL).

Moreover, if there are no available channels in the common spectrum opportunity list (CSOL), the respective transceiver node (14) will broadcast the route request (RREQ) packet towards destination node to look for the new path for data transmission.

As explained above, on-demand routing is performed in the present invention before data transmission. Route request (RREQ) packet is broadcasted from source towards destination node. During the broadcasting of route request (RREQ) packet, every transceiver node (14) will check for the spectrum opportunity (SOP) with the previous one hop node and find the common channel, listing it into common spectrum opportunity list (CSOL). Next, the result for the activation indicator of the related transceiver node (14) will be checked, and the channel that containing the same result for both transceiver node (14) will be listed into basic list (BL).

Thence, the channel intersection of common spectrum opportunity list (CSOL) and basic list (BL) will be listed into superior list (SL). Apart from that, common spectrum opportunity list (CSOL), basic list (BL) and superior list (SL) will still be generated correctly even if a new access point (13) suddenly becomes active with the existing single or multi-channels and also the new single or multi-channels. Once the entire route request (RREQ) packets are being collected at a destination node, it will select the shortest end- to-end delay path for data transmission, based on the information from those packets.

Once the decision is made, it then sends the route reply (RREP) packet back to the source node using the selected path. Data transmission begins right after the route reply (RREP) packet arrives at the source node. During the data transmission, the route maintenance is implemented using spectrum aware methods for the activity of each of the access point (13). Data will be transmitted using the first available channel in superior list (SL). If the channel is no longer available due to the sudden activation of an access point (13), then the transceiver node (14) will switch to the next channel in the list.

If the superior list (SL) is empty, transceiver node (14) will check the available channels in basic list (BL). However, if all the channels in basic list (BL) are no longer available for transceiver node (14), the transceiver node (14) will search the available channel in common spectrum opportunity list (CSOL). Also, the transceiver node (14) will start to broadcast route request (RREQ) packet towards destination if and only if all the channels in common spectrum opportunity list (CSOL) and superior list (SL) are already being used by an access point (13) or unavailable for data transmission. In as much as the present invention is subject to many variations, modifications and changes in detail, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A system for routing in a network comprising:

a backhaul network (11);

at least a router (12) in communication with the backhaul network (11) for providing data traffic through a distribution network;

at least an access point (13) in communication with the router (12) for providing network coverage through at least a channel; and

at least a transceiver node (14) provided with a spectrum sensing module (15), in communication with the access point (13) for providing network connectivity to at least an end user, and communicates with at least another transceiver node (14) for providing continued network connectivity;

characterized in that the transceiver node (14) further comprising a management module (31) in a mutual operation with a cognitive module (32) for selecting a routing path and performing route maintenance;

the management module (31) collects data activity from the spectrum sensing module (15) and allocate channels for selecting a routing path;

the cognitive module (32) analyzes channel availability and utilization by comparing input data received from the management module (31) with the existing data stored in the cognitive module (32).

2. A system for routing in a network in accordance to claim 1, wherein the cognitive module (32) comprising:

a common spectrum opportunity list for recording common channels between each consecutive transceiver node (14);

a basic list generated from the common result of an activation indicator for recording the respective channels between each consecutive transceiver node (14) during indicator activation in the network; and

a superior list generated from the common spectrum opportunity list and the basic list for recording of common intersected channels.

3. A method for routing in a network via the system as described in claim 1, comprises the steps of: receiving route request packet at a transceiver node (14);

processing the route request packet for retrieving and checking information of a source node, a destination node and at least a channel; and

determining whether the transceiver node (14) is the destination node.

4. A method for routing in a network in accordance to claim 3, whenever the transceiver node (14) is the destination node, the method comprises the steps of: selecting routing path from the source node to the transceiver node (14), and sending route reply packet to the source node; and

transmitting data through the selected routing path and performing route maintenance during data transmission.

5. A method for routing in a network in accordance to claim 3, whenever the transceiver node (14) is not the destination node, the method comprises the steps of:

comparing received route request packet with route request packet stored in the transceiver node (14), and dropping the received route request packet for an existing route request packet;

determining a common spectrum opportunity between the source node and the transceiver node (14) for nonexistent route request packet;

analyzing availability of channels and creating a common spectrum opportunity list by comparing the received common spectrum opportunity with common spectrum opportunity data stored in the transceiver node (14);

determining a basic list by comparing the binary decision of the activation indicator between the source node and the transceiver node (14);

determining a superior list from common intersected channels between the common spectrum opportunity list and the basic list; and

transmitting the route request packet to a next transceiver node (14);

6. A method for routing in a network in accordance to claim 4, wherein the method for performing route maintenance comprises the steps of:

retrieving a common spectrum opportunity list, a basic list, and a superior list from the transceiver node (14); determining whether the transceiver node (14) is the destination node; determining whether the superior list is empty; determining availability of channels in the superior list by checking each listed channel through a predetermined sequence; determining whether the basic list is empty; determining availability of channels in the basic list by checking each listed channel through a predetermined sequence; determining whether the common spectrum opportunity list is empty; determining availability of channels in the common spectrum opportunity list and moving a default channel to a subsequent channel; listening to the default channel and transmitting data to a subsequent transceiver node (14) and ensuing towards a destination node; and sending route request packet to the subsequent transceiver node (14) if there no channel is available in the common spectrum opportunity list.

7. A method for routing in a network in accordance to claim 5, wherein the method for determining the common spectrum opportunity list comprises the steps of: retrieving the spectrum opportunities from the route request packet and current transceiver node (14) memory;

setting the channel sequence to default channel;

determining whether the channel existing in spectrum opportunity list of consecutive transceiver node (14) is common;

inserting the channel in common spectrum opportunity list if both nodes share the common spectrum opportunity;

sorting the common spectrum opportunity list in ascending order according to the channel usage ratio of at least an access point (13);

determining whether the number of channels has maxed; and

analyzing the next channel whether the channels are sharing the common spectrum opportunity with neighboring transceiver node (14);

8. A method for routing in a network in accordance to claim 5, wherein the method for determining the basic list comprises the steps of:

retrieving results from activation indicator from a route request packet and data stored in the transceiver node (14) memory; setting the retrieve channels to default channel in order to determine the common activation indicator, and listing channels having common activation indicator into the basic list sorting the updated basic list in ascending order according to the channel usage ratio of at least an access point (13); determining whether the number of channels has maxed; and

updating the current default channel to the next channel.

9. A method for routing in a network in accordance to claim 5, wherein the method for determining the superior list comprises the steps of:

retrieving the common spectrum opportunity list and basic list from the memory stored in the transceiver node (14); setting the current channel to default channel; determining whether the default channel is the common channel between the common spectrum opportunity list and the basic list; updating thereof for an existing common channel between the common spectrum opportunity list and the basic list; sorting the updated superior list in ascending order according to the channel usage ratio of at least an access point (13); determining whether the number of channels has maxed; and

updating the current default channel to the next channel.