WO2009049407A2

WO2009049407A2 - Methods of traffic prioritization in cognitive radio communications

Info

Publication number: WO2009049407A2
Application number: PCT/CA2008/001802
Authority: WO
Inventors: Liang Song
Original assignee: Sennet Communications
Priority date: 2007-10-15
Filing date: 2008-10-15
Publication date: 2009-04-23
Also published as: WO2009049407A3

Abstract

Cognitive radio with the intelligent capabilities of opportunistic spectrum access has been proposed as an enabling element of next generation digital communications. However, the methods of wireless traffic prioritization under cognitive radio systems are missing in prior arts. The invention therefore discloses such traffic prioritization methods which can be applied in diverse cognitive radio implementations. The disclosed methods in principle enforce lower interference probabilities over higher- priority traffics. The spectrum sensing policies are then designed in such a way that higher-priority traffics are associated with clearer spectrum assessments. Moreover, the disclosed methods do not exert any additional communication overhead, so as to maximize the implementation efficiency; and are compatible with the prior arts of traffic prioritization in conventional communication systems. Numerous embodiments are elaborated in the disclosure without deviating from the design principle.

Description

METHODS OF TRAFFIC PRIORITIZATION IN COGNITIVE RADIO COMMUNICATIONS

FIELD OF THE INVENTION

[001] The invention relates to the field of wireless communications. In particular, a set of traffic classes is prioritized in cognitive radio communications, which can opportunistically access radio spectrum resource, and apply prioritized spectrum policies to individual traffic classes.

BACKGROUND OF THE INVENTION

[002] Cognitive radio has been emergent as a driving force of the next generation digital communications. The concept of cognitive radio first appeared in the work of J. Miltola, "Cognitive Radio: Making Software Radios More Personal" (IEEE Personal Communications, vol. 6, no. 4, pp. 13-18, Aug. 1999), which was envisioned as an omnipotent radio with the capability to exploit ambient environments for user centric communications. Since regulation authorities, such as Federal Communication Commission (FCC) in the United States, have recognized the lack of efficiency in legacy static radio spectrum assignments, the researches and developments in cognitive radio have been then focused on the capability of opportunistic spectrum access, such as exemplified by Simon Haykin, "Cognitive Radio: Brain-Empowered Wireless Communications" (IEEE Journal on Selected Areas in Communications, Vol. 23, No. 2, FEB 2006), and I. F. Akyildiz et al "Next Generation / Dynamic Spectrum Access / Cognitive Radio Wireless Networks - A Survey" (Computer Networks Journal, vol. 50, pp. 2127-2159, Sept. 2006). The current industrial standardization in cognitive radio has also been conducted for infrastructure networks, i.e., the IEEE 802.22 WRAN (IEEE Draft Standard for Wireless Regional Area Networks - Part 22 "Cognitive wireless RAN medium access control (MAC) and physical layer (PHY) specifications: policies and procedures for operation in the TV bands") as applied for example in Wireless Regional Area Networks on the Digital Television (DTV) bands.

[003] Methods and apparatus of the large-scale wireless networking with cognitive radios have been disclosed in the prior art, including for example Liang Song, "Methods and Apparatus of Opportunistic Wireless Mesh Networking with Low Power Nodes" (US Patent Application 60/846332), and Liang Song, "Tone Based Cognitive Radio for Opportunistic Communications" (US Provisional Patent Application 60/929071). Within these two cognitive radio principles were proposed for large-scale wireless networking, which are the opportunistic spectrum sensing and spectrum polling, respectively. In the principle of spectrum sensing a first wireless node can opportunistically discover an available wireless channel, a radio spectrum resource, which will not be interfering with other co-located wireless communications. By the principle of spectrum polling, the first wireless node can opportunistically poll neighboring nodes and establish communications onto the chosen wireless channel, the radio spectrum resource, so as to realize certain types of standard inter-node wireless cooperation. Conceptually, the term "opportunistic" suggests that both the utilized radio spectrum and the participating wireless nodes are opportunistically decided by the availability of network resources.

[004] However, such an opportunistic cooperation does not address the use of traffic prioritization as a means to enable or enhance Quality of Service (QoS). Such traffic prioritization being employed typically in prior art store-and-forward packet- switch networks, due to its cost advantages and implementation scalability. A number of examples include:

^■ IP Diffserv (J. Sanjay et al "Engineering Internet QoS," Artech House, Boston MA, 2002);

^■ Wireless Local Area Networks (WLAN) with QoS enhancement (IEEE 802.1 Ie - IEEE Standard for Local and Metropolitan Area Networks- Part 11 "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, Amendment 8: MAC Quality of Service enhancements", 2005);

^■ WiMAX (IEEE 802.16 - IEEE Standard for Local and Metropolitan Area Networks - Part 16 "Air Interface for Fixed Broadband Wireless Access Systems", 2004).

[005] In principle the different classes of traffic within a communications network, e.g. interactive voice/video (VOIP), streaming audio/video, and best-effort data, can all be assigned with different scheduling policies, by which the communication system can apply for example a higher preference to content such as higher-priority voice or video, hi the context of cognitive radio, the concept of prioritization can then be applied to the opportunistic spectrum access policies, where higher-priority traffics should be associated with clearer radio spectrum assessment, and hence would incur smaller interference probability.

[006] However, state-of-the-art technologies have not been able to tackle the need for traffic prioritization in the context of cognitive radio. Moreover, since the current standardization focus is on the IEEE 802.22, which is built upon a conventional star based infrastructure network, then it is the centralized base station deciding the spectrum allocation. Such prior art cognitive spectrum access methods disclosed in for example:

^■ J. Kossi et al in US Patent Application 0084444 (2006) "System and method utilizing a cognitive transceiver for ad hoc networking,"

^■ J. Hui et al in US Patent Application 0117537 (2007) "Method of managing resources in a cognitive radio communication system" and

^■ J. Hui et al in US Patent Application 0117517 (2007) "Method for dynamic frequency selection and system supporting the same in a cognitive radio wireless communication system."

[007] Each of these prior art solutions incurring a lot of communication overhead, and particularly therefore in spectrum sensing results. As all of these prior art methods address complicated communication protocols, such as existing between base-stations and mobile devices according to the standards, they separate the problem of traffic prioritization/management from that of providing a cognitive radio implementation. It would be beneficial however, to reduce this inefficiency of the overall communication systems by combining them.

[008] As a result there is a need to implement and design a method of traffic prioritization within the cognitive radio implementations. It would be beneficial for such designs to operate with little communication overhead, as overhead may not be tolerable in a highly dynamic networking environment subject to volatile traffic load and interference. It would be further advantageous for the adopted approach to accommodate and be compatible with both a range of diverse cognitive radio implementations and conventional contention-based traffic prioritization methods. SUMMARY OF THE INVENTION

[009] The current invention discloses the methods of traffic prioritization in cognitive radio communications. In principle, prioritized spectrum sensing policies are assigned to different classes of traffics. The assignment results in clearer spectrum assessment for higher-priority traffics, which in turn results in lower interference probability. Therefore, by applying the disclosed methods, the communication system with cognitive radios can exert higher preference to higher-priority traffics. The disclosed methods are compatible with diverse cognitive radio implementations, and can also be used in combination with the conventional contention-based traffic prioritization methods designed for conventional communication systems.

[0010] In accordance with the invention there is provided a method of prioritizing traffic comprising the steps of: providing at least one spectral sensing metric of a plurality of spectral sensing metrics, each spectral sensing metric relating to a communication channel; providing at least one spectral sensing threshold of predetermined portion of a plurality of spectral sensing thresholds, the predetermined portion of the plurality of spectral sensing thresholds relating to a class of traffic for transmission on the communication channel; and determining the priority of the class of traffic related to the predetermined portion of the plurality of spectral sensing thresholds in dependence upon at least the at least one spectral sensing threshold and at least one spectral sensing metric.

[0011] In accordance with another embodiment of the invention there is provided a method of transmitting data comprising:

(a) receiving at a node packet of data for transmission therefrom;

(b) associating a class of traffic with the packet of data;

(c) establishing at least an available communication channel of a plurality of potential communication channels;

(d) determining for each available communication channel at least one spectral sensing metric of a plurality of spectral sensing metrics, each spectral sensing metric relating to an aspect of the available communication channel;

(e) comparing the at least one spectral sensing metric with a predetermined spectral sensing threshold of a plurality of spectral sensing thresholds, the predetermined spectral sensing threshold determined in dependence upon at least one of the class of traffic and available communication channel; and

(f) determining in dependence upon at least the comparison whether to transmit the packet of data upon the available communication channel.

[0012] In accordance with another embodiment of the invention there is provided a method of establishing priority for traffic within a network comprising: establishing at least one spectral sensing metric of a plurality of spectral sensing metrics, each spectral sensing metric relating to a communication channel; determining at least one spectral sensing threshold of predetermined portion of a plurality of spectral sensing thresholds, the predetermined portion of the plurality of spectral sensing threshold relating to a class of traffic for transmission on the communication channel; and establishing at least one allowed class of traffic for transmission from a plurality of classes of traffic, the at least one allowed class of traffic being determined in dependence upon at least the at least one spectral sensing threshold and a spectral sensing threshold.

[0013] In accordance with another embodiment of the invention there is provided a method of establishing an acceptable transmission criteria comprising: monitoring at least a characteristic of at least one potential communication channel of a plurality of potential communication channels; establishing for the at least one potential characteristic a spectral sensing threshold in dependence upon at least the characteristic, the spectral sensing threshold relating to a condition of acceptable transmission quality.

[0014] In accordance with another embodiment of the invention there is provided a method of prioritizing traffic within a network comprising: establishing at least one spectral sensing threshold of predetermined portion of a plurality of spectral sensing thresholds, each spectral sensing threshold being associated with a class of traffic for transmission; receiving a packet of data for transmission associated with a class of traffic; establishing a pool of available communication channels, the pool of available channels being those communications channels for which at least one spectral sensing metric is determined within a predetermined period of time at least one of prior to and subsequent to receiving the packet of data; establishing a pool of acceptable communications channels, the pool of acceptable communications channels being those available communication channels wherein the determined at least spectral sensing metric satisfies the spectral sensing threshold associated with the class of traffic of the packet of data; opportunistically determining an available communications channel from the pool of acceptable communications channels; and transmitting the packet of data on the available communications channel

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Exemplary embodiments of the invention will now be described in conjunction with the following drawings, in which:

[0016] Fig. 1 shows a contention-based traffic prioritization method according to the prior art;

[0017] Fig. 2 shows a diagram for use in traffic class thresholding for traffic prioritization in cognitive radio implementations;

[0018] Fig. 3A shows a diagram for use in traffic class thresholding for traffic prioritization in a tone-based cognitive radio implementation;

[0019] Fig. 3B shows a diagram for use in traffic class thresholding for traffic prioritization in a tone-based cognitive radio implementation;

[0020] Fig. 4 shows a simplified block diagram of a circuit for performing thresholding comparisons in traffic prioritization; and

[0021] Fig. 5 shows a combination of traffic diagram for prioritization of cognitive radios and conventional communication systems.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0022] Referring to Fig. 1 depicted is a conventional contention-based traffic prioritization method 100 where all traffic load shares the same spectrum, or wireless medium. The method conforms to the prior art defined in IEEE 802.1 Ie (Wireless Local Area Networks (WLAN) with QoS enhancement (IEEE 802.1 Ie - IEEE Standard for Local and Metropolitan Area Networks- Part 11 "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, Amendment 8: MAC Quality of Service enhancements", 2005). Specifically, every traffic class k, k being an integer, is assigned with a fixed time period parameter AIFS[Jc], where AIFS stands for arbitrary inter-frame space, satisfying AIFS[J ]<AIFS[2] <... <AIFS[KJ.

[0023] The first status bar 110 shows the medium access of the class I traffic: where after the period of Busy Medium 111, a clear medium assessment, made for example via carrier sensing, is obtained at a transmitter, and wherein a scheduler backs off for the period AIFS[I] 112 and a random first Contention Window 113. The first Contention Window 113 is a random time period generated by a random number in [0, CW], where CW is an adjustable constant decided by the maximal contention window length. If the medium stays cleared during the back-off period, the scheduler at the transmitter follows with the Next Frame 114 transmission, otherwise the current transmitter loses the medium access contention and waits for the next round opportunity of clear medium assessment.

[0024] In comparison, the second status bar 120 shows the medium access of the class 2 traffic, whereas the third status bar 130 shows the medium access of class K traffic. The only differences among the status bars 110, 120, and 130 are the AIFS parameters. Since AIFS[k]<AIFS[k+I], given any 0<k<K, the class k traffics which have higher priority level than the class k+1 traffics, can obtain better chance to win the wireless medium contention than the class k+I traffics.

[0025] In cognitive radio communications, cognitive radio can opportunistically access radio spectrum resources, which can be composed of a number of wireless channels. These wireless channels can be differentiated by different frequencies, spreading codes (e.g., in CDMA), or other unique signal signatures in the system. Without loss of generality, assume here that there are altogether N wireless channels. A spectrum sensing module in cognitive radio can monitor the N wireless channels, where a spectrum sensing metric SSL[n] can be derived for every wireless channel n. Here SSL stands for spectrum sensing level, which can be obtained by a variety of processes including energy detection (carrier sensing), matched filter detection, or cyclostationary detection (see for example W. Gardner, "Signal interception: A unifying theoretical framework for feature detection," IEEE Trans. Commun., vol. 36, pp. 897-906, Aug. 1988).

[0026] SSL can be derived solely at the local cognitive radio; alternatively it is obtained by the combined measurements with neighboring cognitive radios. In principle, SSLfn] indicates the current interference level of the wireless channel n, where lower SSLfn] suggests clearer radio spectrum assessment.

[0027] This reveals a major difference between cognitive radio communications and conventional contention-based communications. In conventional systems, since all radios share the same wireless medium, the prioritization method gives higher- priority traffic a better chance to occupy the wireless medium, whereas lower-priority traffic should wait for the complete transmission of higher-priority traffic. In cognitive radio systems, a significant number of wireless channels are portentially opportunistically accessed by each radio. With the assumption of sufficient amount of bandwidth then traffic load, i.e. data frames, always find an available wireless channel for transmission without back-off delay. Therefore, higher-priority traffic selects a clearer wireless channel, i.e., with lower interference probability, which gives an outline of embodiments of traffic prioritization methods in cognitive radio implementations, as shown with cognitive cooperation 200 in Fig. 2 between cognitive radio (CR) transmitter 201 and CR receiver 202.

[0028] As shown in traffic class graph 210 every traffic class, determined by integer class value k, has a threshold, being arbitrary spectrum sensing thresholds, satisfying ASST[I J <ASST[2J<... <ASST[KJ. As shown in traffic class graph 210, the spectrum sensing level of a wireless channel n, SSL[n] 216 is below ASST[I] 211; the spectrum sensing level of another wireless channel m, SSL[m] 215, is between ASST [2] 212 and ASST [3] 213. Therefore, the traffic prioritization policy is defined by:

^■ all the traffic classes can access the wireless channel n;

^■ only the traffic classes with the index k>2, can access the wireless channel m, which may be subject to higher interference level.

[0029] The above described process of traffic prioritization can also contribute to limiting the interference from the current wireless transmission to other wireless communications. Since higher-priority traffic is usually associated with higher transmitting power, it helps to compensate the level of interference injected into the network, by enforcing a lower ASSTp]. The benefits of using of higher transmitting power for higher-priority traffic are straight-forward, but are not directly related to the cognitive radio design itself. Such implementations have appeared in the descriptions of embodiments of cognitive networks, such as L. Song supra (US Patent Application No. 60/846332).

[0030] Now referring to Figs. 3 A and 3B an embodiment of a traffic prioritization method in a tone-based cognitive radio implementation is shown. The CR state diagram 300 shows a state diagram of the tone-based cognitive radio, such as described supra by L. Song (US Patent Application 60/929071). Particularly, within a defined wireless channel n, every data channel is further associated with two distinctive tones, which are the polling tone Pn, and the sensing tone Sn, respectively. Furthermore, the abstract wireless linkage is defined as an arbitrary abstraction of wireless nodes' cooperation in proximity areas, which is composed of a first node and a group of second nodes. Therefore, on initiating an abstract wireless link with process 302, a wireless node senses for an available wireless channel n, which has a vacant data channel, and vacant polling tone Pn and sensing tone Sn, respectively. Here "vacant" suggests that the spectrum sensing levels on the corresponding signals are below some predetermined thresholds. Shown in the CR state diagram 300, the wireless node then transfers from the IDLE state 301 to the First Node state 304 and broadcasts the polling tone Pn. On detecting Pn 306, the available nodes around the first node can join in the initiated abstract wireless link based on their autonomous decisions, which then transfer to the Second Nodes state 305, and broadcast the sensing tone Sn. Hence, both the sensing and polling tones can protect the abstract wireless link from interferences. Subsequently upon completion of an opportunistic abstract wireless link transmission, the wireless node exits the First Node state 304 and returns to the IDLE state 301 by process 303 clearing the polling tone Pn.

[0031] Similarly the other nodes in exiting the Second Nodes state 305 to return to the IDLE state 301 clear the sensing tone Sn in process 307. Therefore, the spectrum sensing at the first node and the second nodes, on a wireless channel n, is composed of the data channel, the polling tone Pn, and the sensing tone Sn, respectively. Now referring to first and second power graphs 310 and 320 respectively in Fig. 3B then for a wireless channel n, SSDLfn] 317, SSPLfnJ 316, and SSSLfn] 315 represent the spectrum sensing levels of the data channel, the polling tone, and the sensing tone, respectively. The traffic prioritization method assigns every supported traffic class k with two thresholds, which are the arbitrary spectrum sensing thresholds for data channels, ASSDT[U] 321 through 324 in second power graph 320, and for sensing/polling tones ASSTT[Jt] 311 through 314 in first power graph 310. As presented in second power graph 320 the data channel powers 321 through 324 satisfy ASSDT[1]< ASSDT[2]<... <ASSDT[K], and similarly in first power graph 310, ASSTT[1]< ASSTT[2]<... <ASSTT[K].

[0032] As shown in Fig 3B for a wireless channel n, SSDL[n] 325 lies between ASSDT[I] 321 and ASSDT [2] 322; SSPL[n] 315 lies between ASSTT [2] 312 and ASSTT [3] 313; and SSSL[n] 316 lies below ASSTT[I] 311. By combination, only the traffic classes with the index k>2 can access the channel n, satisfying a prioritization policy. Therefore, more generally in accommodating other cognitive radio implementations, where there exist M types of spectral sensing level metrics the following basis of prioritization may be established according to the embodiment. The traffic prioritization methods optionally assign arbitrarily Q sets of arbitrary spectrum sensing thresholds, where each satisfies the condition that Q is less than or equal to M. Then, every one of the M types of spectral sensing level metrics on a wireless channel can be applied to one of the Q sets of arbitrary spectrum sensing thresholds. By the combination of the comparisons, it can be decided which subset of the K traffic classes can access the wireless channel. The determination of these thresholds is typically dependent upon characteristics of the CR radio implementation, for example transmitting power, modulation format, coding algorithm, and spectrum resources. Such thresholds may then be adapted to the requested interference probabilities over the different ^traffic classes.

[0033] Now referring to Fig. 4 there is illustrated an embodiment 400 of traffic prioritization methods. Here SSlL[n] 401, SS2L[n] 402, SS3L[n] 403, ..., SSML[n] 404, represent the M spectral sensing metrics on a wireless channel n. ASS IT [h] 411, ASS2T[k] 412, ..., ASSQT[n] 413 represent the Q arbitrary spectrum sensing thresholds for a traffic class k. As shown in embodiment 400, SSl L[n] 401 and SS2L[n] 402 are assigned to ASSlT[U] 411 in this particular example; SS3L[n] 403 and SSML[n] 404 are assigned to ASS2T[k] 412 and ASSQTfn] 413, respectively. A set of comparators 421 - 424 are further utilized. For example, the output value of the comparator 421 is "1" if the input values satisfy that ASSlT [k] 411 is greater than SSILfnJ 401; and it is "0" otherwise. A logic AND gate 430 is then utilized, whose output 431 equals "1" if the conditions ASSITfkJ (411) > SSILfnJ (401), ASSITfk] (411) > SS2L[n] (402), ASS2T[k] (412) > SS3L[n] (403), ASSQTfn] (413) > SSMLfn] (404), as exemplified within embodiment 400 are satisfied. Therefore, if the output value 431 equals "1", it suggests that the class k traffics are admissible on the wireless channel n; otherwise, it suggests that the interference probability on the wireless channel n can be too high for accommodating the class £ traffics.

[0034] Furthermore, referring to Fig. 5 there is shown a combined embodiment 500 demonstrating that the traffic prioritization methods of cognitive radio are useful in combination with the conventional contention-based traffic prioritization methods. Such combination is useful where the number of wireless channels N is limited subject to the applied traffic load. Under such circumstances, multiple traffics can be locating the same wireless channel n simultaneously. In Fig. 5, taking the notations as used previously in respect of Fig. 2, and under the condition 501 ASSTfk- l]<SSL[n]<ASST[k], then traffic classes with lower priority level than the class k-1, namely those having an index larger than or equal to k, are admissible to the wireless channel n. The status bars 510 through 520 show the further traffic prioritization on the wireless channel n, which is similar to the method presented in Fig 1. The difference is noted that only the traffic classes with the index larger than or equal to k, are admissible in the channel contention. Accordingly, the Busy Medium 111 period in Fig 1 is replaced with the process of spectrum sensing 511. Similarly to Fig. 1, traffic classes with higher priority are also assigned with smaller arbitrary inter-frame space AIFS, by which they can win better chances to occupy the wireless channel in the limited medium contention. In this manner each status bar 510 through 530 is composed of AIFS 512, contention window 513 and next frame 514.

[0035] Numerous other embodiments may be envisaged without departing from the spirit or scope of the invention.

Claims

ClaimsWhat is claimed is:

1. A method comprising: providing a data packet having an associated first class of transmission; sensing a first spectral sensing metric for a first available communication channel; sensing a second spectral sensing metric for a second available communication channel; comparing the spectral sensing metric and the second spectral sensing metric to provide a second comparison result; and, when at least one of the first spectral sensing metric and the second spectral sensing metric is indicative of supporting the class of transmission, transmitting the data packet via one of the first available communication channel and the second available communication channel selected in dependence upon the second comparison result.

2. A method according to claim 1 comprising: providing for each of a plurality of classes of transmission a spectral sensing threshold; and comparing the first spectral sensing metric and the spectral sensing threshold to determine a first comparison result; and comparing the second spectral sensing metric and the spectral sensing threshold to determine a third comparison result; and wherein the comparison results are indicative of supporting the class of transmission when at least one of the first spectral sensing metric and the second spectral sensing metric exceeds the spectral sensing threshold associated with the class of transmission.

3. A method according to any of claims 1 and 2 wherein the channel is selected such that a channel supporting a lowest class of transmission including the class of transmission is selected.

4. A method according to any of claims 1 through 3 wherein the channel is selected such that a channel supporting a highest class of transmission including the class of transmission is selected.

5. A method according to any of claims 1 through 4 wherein the channel is selected such that a channel supporting a highest class of transmission exceeding a predetermined waiting period.

6. A method according to any of claims 1 through 5 wherein sensing the spectral sensing metric and sensing the second spectral sensing metric comprise: providing a receiver monitoring at least a characteristic of the available communication channel and the second available communication channel and determining in dependence on the at least a characteristic the spectral sensing metric and the second spectral sensing metric.

7. A method according to any of claims 1 through 6 wherein, a network for transmitting data associated with the class of traffic is from the group consisting of an ad hoc network, an opportunistic network, and a cognitive radio based network.

8. A method according to any of claims 1 through 7 wherein, determining the priority of the class of traffic is performed in dependence upon a predetermined wireless network standard selected from a group consisting of Orthogonal Frequency-Division Multiple Access (OFDMA), Coded Orthogonal Frequency-Division Multiple Access, Code Division Multiple Access (CDMA), Time Division Multiplexing (TDM), Frequency Division Multiple Access (FDMA), Frequency-Hopping Spread Spectrum (FHSS), and Direct-Sequence Spread Spectrum (DSSS).

9. A method comprising: providing a data packet having an associated first class of transmission; sensing a spectral sensing metric for an available communication channel; and, when the available communication channel has an associated spectral sensing metric indicative of supporting the class of transmission, transmitting the data packet via the available communication channel.

10. A method according to claim 9 comprising: providing for each of a plurality of classes of transmission a spectral sensing threshold; and comparing the spectral sensing metric and the spectral sensing threshold to determine a comparison result; and wherein when the comparison result is indicative of one of the available communication channel supporting the class of transmission and the available communication channel other than supporting the class of transmission.

11. A method according to claim 10 wherein, the comparison result is indicative of one of the available communication channel supporting the class of transmission when the spectral sensing metric exceeds the spectral sensing threshold associated with the class of transmission.

12. A method according to claim 10 comprising: sensing a second spectral sensing metric for a second available communication channel; comparing the spectral sensing metric and the second spectral sensing metric to provide a second comparison result; and, when the second available communication channel has an associated second spectral sensing metric indicative of supporting the class of transmission, transmitting the data packet via one of the available communication channel and the second available communication channel selected in dependence upon the second comparison result.

13. A method comprising:

(a) receiving at a node a packet of data for transmission therefrom;

(b) associating a class of traffic with the packet of data;

(c) establishing a set of available communication channels;

(d) determining for each of the set of available communication channels at least one spectral sensing metric relating to an aspect of said communication channel; (e) comparing the at least one spectral sensing metric with a predetermined spectral sensing threshold associated with the class of traffic to determine a comparison result; and,

(f) determining in dependence upon comparison result whether to transmit the packet of data and if so, on which of the set of available communication channels to transmit the packet of data.

14. A method according to claim 13 wherein, determining in dependence upon at least the comparison comprises: determining to transmit when the at least one spectral sensing metric satisfies a predetermined condition with respect to the predetermined spectral sensing threshold and transmitting the packet of data; and, determining to other than transmit when the at least one spectral sensing metric satisfies a predetermined condition with respect to the predetermined spectral sensing threshold and adjusting the class of traffic prior to repeating steps (e) and (f).

15. A method according to claim 14 wherein, adjusting the class of traffic comprises adjusting the class of traffic to one associated with a reduced priority of transmission.

16. A method according to any of claims 13 through 15 wherein, at least one of the set of available channels comprises a wireless channel.

17. A method according to any of claims 13 through 16 wherein, establishing a set of available communication channels comprises opportunistically establishing at least an available communication channel within the set of available communication channels in dependence upon at least one of a polling tone and a sensing tone.

18. A method according to any of claims 13 through 17 comprising: step (d) comprises: providing a receiver monitoring at least a characteristic of a predetermined portion of the set of available communication channels; and, determining in dependence upon the at least a characteristic the at least one spectral sensing metric.

19. A method according to any of claims 13 through 18 wherein, each channel of the set of available channels consists of at least one of a channel operating according to a predetermined wireless network standard, a channel operating according to predetermined cognitive radio standard, and a channel operating according to a standard selected from the group comprising Orthogonal Frequency-Division Multiple Access (OFDMA), Coded Orthogonal Frequency- Division Multiple Access, Code Division Multiple Access (CDMA), Time Division Multiplexing (TDM), Frequency Division Multiple Access (FDMA), Frequency- Hopping Spread Spectrum (FHSS), and Direct-Sequence Spread Spectrum (DSSS).

20. A method comprising: establishing at least one spectral sensing metric relating to a communication channel; determining a spectral sensing threshold relating to a class of traffic for transmission on the communication channel; and establishing at least one allowed class of traffic for transmission within a known channel, the at least one allowed class of traffic determined in dependence upon the spectral sensing threshold and a spectral sensing metric.

21. A method according to claim 20 wherein, providing the spectral sensing threshold comprises extracting the spectral sensing threshold from a digital memory storing data associated with a plurality of spectral sensing thresholds, the plurality of spectral sensing thresholds relating to a plurality of classes of traffic for transmission.

22. A method according to any of claims 20 through 21 wherein, each class of traffic relates to at least one digital data, on demand multi-media entertainment, video telephony, audio telephony, voice over Internet protocol, text messaging, and multi-media content relating to a game.

23. A method comprising: monitoring at least a characteristic of a plurality of communication channels; establishing for the at least a characteristic at least a spectral sensing threshold relating to a condition of transmission quality relating to the at least a characteristic.

24. A method according to claim 23 wherein the at least a spectral sensing threshold relates to at least a class of transmission and comprising:

(a) receiving a data packet having associated therewith a first class of transmission;

(b) determining upon receiving the data packet a plurality of spectral sensing metrics, each spectral sensing metric relating to a communication channel;

(b) establishing a transmission decision for the data packet in dependence upon the plurality of sensing metrics, the at least a spectral sensing threshold relating to the first class of transmission.

25. A method according to claim 24 wherein establishing the transmission decision comprises transmitting the data packet on a communication channel having a spectral sensing metric sufficient for supporting the first class of transmission.

26. A method according to claim 24 wherein, establishing the transmission decision comprises performing a traffic class analysis comprising comparing the spectral sensing metrics with the spectral sensing thresholds to determine a set of second communications channels, communication channels within the set having spectral sensing metrics within corresponding spectral sensing thresholds; and selecting a transmission channel for the data packet from the set of second communications channels.

27. A method according to claim 26 wherein, the set of second communications channels includes channels having associated spectral sensing thresholds indicative of at least one of reduced transmission quality, increased transmission power, and reduced effective transmission rate compared to another spectral sensing threshold.

28. A method according to claim 26 whe ^~in. channels within the set of second communication channels have associated spectral sensing thresholds indicative of at least one of increased noise, increased cost of transmission, increased bit error rate, increased interference, and reduced probability of successful transmission.

29. A method comprising: receiving for transmission a packet of data associated with a class of traffic; establishing a spectral sensing threshold associated with the class of traffic for transmission; determining a spectral sensing metric for each of a set of first communication channels, the set of first channels comprising communication channels for which a spectral sensing metric is determined; establishing a set of second communication channels, the set of second communication channels comprising at least a communication channel of the first communication channels having a determined spectral sensing metric within the spectral sensing threshold; opportunistically determining a transmit communication channel from the set of second communications channels for transmitting the packet of data therein; and transmitting the packet of data on the transmit communication channel.

30. A method according to claim 29 wherein the spectral sensing metric is determined within a predetermined period of time about receiving the packet of data

31. A method according to claim 29 wherein, establishing a set of second communication channels comprises opportunistically determining using a polling signal and a sensing signal the transmit communication channel in accordance with at least one of a cognitive radio standard, an ad-hoc wireless networking standard, and an opportunistic wireless standard.

32. A method according to claim 31 wherein, at least one of the polling signal and sensing signal are continuous unmodulated tones associated with a transmission channel associated with a predetermined center frequency and predetermined band according to the standard.

33. A method according to claim 32 wherein, the wireless networking standard is selected from a group consisting of Orthogonal Frequency-Division Multiple Access (OFDMA), Coded Orthogonal Frequency-Division Multiple Access, Code Division Multiple Access (CDMA), Time Division Multiplexing (TDM), Frequency Division Multiple Access (FDMA), Frequency-Hopping Spread Spectrum (FHSS), and Direct-Sequence Spread Spectrum (DSSS).