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WO2008123834A1 - Procédé pour le fonctionnement d'un dispositif de radiocommunications ultra large bande - Google Patents

Procédé pour le fonctionnement d'un dispositif de radiocommunications ultra large bande Download PDF

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Publication number
WO2008123834A1
WO2008123834A1 PCT/SG2008/000113 SG2008000113W WO2008123834A1 WO 2008123834 A1 WO2008123834 A1 WO 2008123834A1 SG 2008000113 W SG2008000113 W SG 2008000113W WO 2008123834 A1 WO2008123834 A1 WO 2008123834A1
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WIPO (PCT)
Prior art keywords
communication device
ultra
radio communication
frequency channel
wideband radio
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PCT/SG2008/000113
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English (en)
Inventor
Ananth Subramanian
Po Shin Francois Chin
Xiaoming Peng
Khiam Boon Png
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Agency for Science Technology and Research Singapore
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Agency for Science Technology and Research Singapore
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Publication of WO2008123834A1 publication Critical patent/WO2008123834A1/fr
Anticipated expiration legal-status Critical
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/06—Reselecting a communication resource in the serving access point

Definitions

  • Embodiments of the invention relate to the field of wireless ultra-wideband radio communication systems, such as ad hoc wireless ultra-wideband radio communication systems, for example.
  • embodiments of the invention relate to a method of operating an ultra-wideband radio communication device, as well as a corresponding communication device.
  • a cognitive radio system operates in frequency channels that have already been allocated or licensed for a specific communication service.
  • this specific communication service is typically referred to as the incumbent service, and existing users of the incumbent service are known as incumbent users (or primary users).
  • the cognitive radio system is able to co-exist with the incumbent users in the allocated frequency channels, by 'opportunistically' using the portions of the allocated frequency channels which are not used by the incumbent users, perhaps, at certain locations or during specific times.
  • the cognitive radio system tries to search for an unused frequency channel and once such an unused frequency channel is found, the cognitive radio system may then proceed to operate in this unused frequency channel.
  • the cognitive radio system should continue to periodically detect for the resumption of any signal transmission by the incumbent user, across the same range of frequency channels, including the frequency channel in which it is operating. Should the cognitive radio system detect that there is a signal transmission by incumbent users in the frequency channel which it is operating in, it must avoid interfering with the operation of the incumbent users.
  • a method for operating an ultra-wideband radio communication device includes generating a channel changing negotiating message including information about at least one frequency channel the ultra-wideband radio communication device intends to change to.
  • the method provided further includes transmitting the channel changing negotiating message to at least one other ultra-wideband radio communication device with which the ultra-wideband radio communication device has an established communication connection in a current frequency channel.
  • the ultra-wideband radio communication device may receive channel changing negotiating messages from the at least one other ultra-wideband radio communication device, where the channel changing negotiating messages include information about at least one frequency channel the other ultra-wideband radio communication device intends to change to.
  • the ultra-wideband radio communication device may determine whether the ultra-wideband radio communication device is able to change to the at least one frequency channel included in the channel changing negotiating message, and may generate a further channel changing negotiating message including information about at least one frequency channel the ultra-wideband radio communication device intends to change to.
  • the ultra-wideband radio communication device may then transmit the further channel changing negotiating message to the other ultra-wideband radio communication device.
  • the ultra-wideband radio communication device may select, based on a predetermined criterion, the frequency channel to change to, if the ultra- wideband radio communication device is the initiator of the intended change of frequency channel.
  • Figure 1 shows a communication system according to an embodiment of the invention.
  • Figure 2 shows a flow diagram describing a method of operating an ultra- wideband radio communication device according to one embodiment of the invention.
  • Figures 3 (a) - (e) show the contents and the content formats of a Channel Consensus (CC) Information Element according to one embodiment of the invention.
  • Figure 4 shows a flow diagram of another method of operating an ultra- wideband radio communication device, according to one embodiment of the invention.
  • Figure 5 shows a table used in the illustration of a first criterion for determining which frequency channel to switch to, according to one embodiment of the invention.
  • Figure 6 shows a table used in the illustration of a second criterion for determining which frequency channel to switch to, according to one embodiment of the invention.
  • Figures 7 (a) - (c) show three tables used in the illustration of a third criterion for determining which frequency channel to switch to, according to one embodiment of the invention.
  • Figures 8 (a) - (b) show a flow diagram of an exemplary illustration of how one embodiment of the invention may be implemented.
  • each communication device typically does not have the same control information as the other communication devices.
  • the control information may be the unused frequency channels available to other communication devices of the communication system.
  • transmitting all the control information all the time in order to ensure that all communication devices have all control information may be too cumbersome and too expensive.
  • the communication device in order to enable each communication device in a group to switch to the same frequency channel, the communication device first initiates an information exchange process by transmitting a message which includes information on the frequency channels it is willing to switch to. A first neighboring communication device then transmits a reply message which includes information on the frequency channels it is willing to switch to.
  • the information on the frequency channels which the first neighboring communication device is willing to switch to may only include the frequency channels which the first neighboring communication device as well as the communication device are willing to switch to, and not all the frequency channels which the first neighboring communication device itself is willing to switch to.
  • the process of exchanging information about frequency channels the devices are willing to switch to carries on for a predetermined time interval, during which the communication device will receive at least one reply message.
  • the communication device which initiated the information exchange process will decide on which frequency channel to switch to based on a predetermined criterion. It can be seen that with such an information exchange process, the communication device is able to decide on a frequency channel which at least one neighboring communication device and itself in the group are willing to switch to.
  • a method for operating an ultra- wideband radio communication device includes generating a channel changing negotiating message including information about at least one frequency channel the ultra-wideband radio communication device intends to change to.
  • the method provided further includes transmitting the channel changing negotiating message to at least one other ultra-wideband radio communication device with which the ultra- wideband radio communication device has an established communication connection in a current frequency channel.
  • frequency band refers to a predefined contiguous frequency range, which may be used for signal transmissions.
  • a frequency band is often referred to using a (frequency) band number associated with it.
  • frequency channel refers to a combination of one or more frequency bands, and such a combination may be used for signal transmissions as well.
  • a frequency channel may or may not have a contiguous frequency range.
  • a frequency channel is often referred to using a frequency channel number associated with it.
  • band group refers to a group of frequency bands.
  • a band group may not be used for signal transmissions. It should be noted that it is possible that a frequency channel may have the same frequency bands as a band group.
  • a method for operating an ultra- wideband radio communication device includes receiving, via an established communication connection with another ultra-wideband radio communication device in a current frequency channel, a channel changing negotiating message including information about at least one frequency channel the other ultra-wideband radio communication device intends to change to, and determining whether the ultra-wideband radio communication device is able to change to the at least one frequency channel included in the channel changing negotiating message.
  • the method provided further includes generating a further channel changing negotiating message including information about at least one frequency channel the ultra-wideband radio communication device intends to change to, and transmitting the further channel changing negotiating message to the other ultra-wideband radio communication device.
  • a method for operating an ultra- wideband radio communication device includes the ultra-wideband radio communication device detecting a signal energy level, and comparing the detected signal energy level with a first energy threshold value and a second energy threshold value, wherein the second energy threshold value is greater than the first energy threshold value.
  • the method provided further includes the ultra-wideband radio communication device nulling tones in at least one frequency range in case that the detected signal energy level lies in a range defined by the first energy threshold value and the second energy threshold value.
  • a method for operating an ultra- wideband radio communication device includes the ultra-wideband radio communication device detecting a signal energy level, and comparing the detected signal energy level with a first energy threshold value and a second energy threshold value, wherein the second energy threshold value is greater than the first energy threshold value.
  • the method provided further includes the ultra-wideband radio communication device changing at least one frequency channel in case that the detected signal energy level is greater than the second energy threshold value.
  • an ultra-wideband radio communication device includes a generation unit configured to generate a channel changing negotiating message including information about at least one frequency channel the ultra- wideband radio communication device intends to change to, and a transmission unit configured to transmit the channel changing negotiating message to at least one other ultra-wideband radio communication device with which the ultra-wideband radio communication device has an established communication connection in a current frequency channel.
  • an ultra-wideband radio communication device includes a receiver unit configured to receive, via an established communication connection with another ultra-wideband radio communication device in a current frequency channel, a channel changing negotiating message including information about at least one frequency channel the other ultra-wideband radio communication device intends to change to, a determination unit configured to determine whether the ultra-wideband radio communication device is able to change to the at least one frequency channel included in the channel changing negotiating message, a generation unit configured to generate a further channel changing negotiating message including information about at least one frequency channel the ultra-wideband radio communication device intends to change to, and a transmission unit configured to transmit the further channel changing negotiating message to the other ultra-wideband radio communication device.
  • an ultra-wideband radio communication device includes a detection unit configured to detect a signal energy level, a comparison unit configured to compare the detected signal energy level with a first energy threshold value and a second energy threshold value, wherein the second energy threshold value is greater than the first energy threshold value, and a null tone unit configured to null tones in at least one frequency range in case that the detected signal energy level lies in a range defined by the first energy threshold value and the second energy threshold value.
  • an ultra-wideband radio communication device includes a detection unit configured to detect a signal energy level, a comparison unit configured to compare the detected signal energy level with a first energy threshold value and a second energy threshold value, wherein the second energy threshold value is greater than the first energy threshold value, and a frequency channel change unit configured to change at least one frequency channel in case that the detected signal energy level is greater than the second energy threshold value.
  • the channel changing negotiation message further comprises information on whether or not the ultra-wideband radio communication device is the initiator of the intended change of frequency channel.
  • the method provided further includes selecting, based on a predetermined criterion, the frequency channel to change to, if the ultra- wideband radio communication device is the initiator of the intended change of frequency channel.
  • the predetermined criterion includes the frequency channel selected being the frequency channel which has the smallest frequency channel number difference from the frequency channel number of the currently used frequency channel. In another embodiment, the predetermined criterion further includes the frequency channel selected being the frequency channel which has the smallest frequency channel number. In yet another embodiment, the predetermined criterion further includes the frequency channel selected being the frequency channel which has the smallest frequency channel number where most of the other ultra-wideband radio communication devices with which the ultra-wideband radio communication device has an established communication connection in a current frequency channel are able to switch to. In one embodiment, the frequency channel number is a logical frequency channel number. In another embodiment, the frequency channel number is a WiMedia frequency channel number.
  • the selection of the frequency channel is carried out after a predetermined time interval. In another embodiment, the selection of the frequency channel is carried out after having received at least one further channel changing negotiating message.
  • the channel changing negotiation message further includes information on whether or not the ultra-wideband radio communication device is able to switch from the current frequency channel. In another embodiment, the channel changing negotiation message further includes information on whether or not the ultra-wideband radio communication device detects a signal, which has an energy level greater than a predetermined energy threshold value.
  • the method provided further includes determining for each of a plurality of ultra-wideband radio communication devices a set of frequency channels which the respective ultra-wideband radio communication device intends to switch to. In another embodiment, the method provided further includes selecting a frequency channel which is in the set of frequency channels for each ultra-wideband radio communication device, and switching to the selected frequency channel. In yet another embodiment, the method provided further includes selecting a frequency channel which is in the set of frequency channels that each ultra-wideband radio communication device is able to switch to, and switching to the selected frequency channel.
  • the channel changing negotiating message includes information about a first set of frequency channels the other ultra-wideband radio communication device intends to change to, the further channel changing negotiating message includes information about a second set of frequency channels the ultra-wideband radio communication device intends to change to, and the second set is a subset of the first set.
  • the signal may be an interference signal, an alternate service signal or an incumbent service signal.
  • the signal energy level is detected of a signal which includes at least one frequency in the at least one frequency range.
  • the ultra-wideband radio communication device continues using the current frequency channel in case that the detected signal energy level is below the first energy threshold value.
  • the first energy threshold is in the range from about - 8OdBm to about -55dBm and wherein the second energy threshold is in the range from about -55dBm to about -1OdBm. In another embodiment, the first energy threshold is about -6OdBm and wherein the second energy threshold is about -45dBm.
  • the method provided further includes transmitting a message to the other communication device with which the communication device communicates using the at least one frequency range, wherein the message comprises the information on the tones which are to be nulled in the at least one frequency range.
  • the method provided further includes the ultra-wideband radio communication device changing at least one frequency channel in case that the detected signal energy level is greater than the second energy threshold value.
  • the method provided further includes the ultra-wideband radio communication device nulling tones in at least one frequency range in case that the detected signal energy level lies in a range defined by the first energy threshold value and the second energy threshold value.
  • the ultra-wideband radio communication device is an ad hoc radio communication device.
  • the ultra-wideband radio communication device is a WiMedia communication device. In another embodiment, the ultra-wideband radio communication device is a Bluetooth communication device.
  • the ultra-wideband radio communication device is a Firewire communication device. In another embodiment, the ultra-wideband radio communication device is a Certified Wireless Universal Serial Bus (USB) communication device.
  • USB Universal Serial Bus
  • Fig. 1 shows a communication system 100 according to an embodiment of the invention.
  • the communication system 100 includes a first communication device (A) 101 , a second communication device (B) 103 and a third communication device (C) 105.
  • the area inside circle 107 represents the area in which a signal transmission from the first communication device (A) 101 can be received.
  • the area inside circle 109 represents the area in which a signal transmission from the third communication device (C) 105 can be received.
  • the second communication device (B) 103 is able to receive the signal transmissions from both the first communication device (A) 101 and the third communication device (C) 105. It can also be seen that the first communication device (A) 101 is not able to receive the signal transmission from the third communication device (C) 105, and vice versa. In one instance, the first communication device (A) 101 detects a signal transmission from the first interferer communication device (D) 111.
  • an interferer communication device refers to an incumbent service user (communication device), which happens to use the same frequency channel for its signal transmission.
  • the first communication device (A) 101 needs to take some action in order to avoid interfering with the signal transmission of the first interferer communication device (D) 111.
  • the first communication device (A) 101 may, for example, move its operations (including signal transmissions) to another unused frequency channel.
  • the first communication device (A) 101 may be in the midst of transferring a large data file, for example, to the third communication device (C) 105, and the file transfer is not yet completed.
  • the file transfer operation it would be ideal if all three communication devices (A, B and C) could move its operations to the same unused frequency channel, in order that the file transfer operation may continue. If any one of the three communication devices were to move its operations to a first unused frequency channel while the other two of the three communication devices move their operations to a second unused frequency channel, where the first unused frequency channel is different from the second unused frequency channel, the file transfer operation could no longer continue as can be seen.
  • the first communication device (A) 101 may be able to move its operations to, say, the first unused frequency channel, but the second communication device (B) 103 and the third communication device (C) may not, due to the presence of signal transmissions of a second interferer communication device (E) 113 in the first unused frequency channel, for example.
  • Such a scenario should also be accounted for in a mechanism for enabling all three communication devices (A, B and C) to move their operation to the same unused frequency channel.
  • the communication system 100 may represent an ultra- wideband radio communication system, such as the WiMedia communication system, for example.
  • the WiMedia communication system operates in the frequency range between 3.1 GHz and 10.6 GHz, which have already been allocated for the use by communication services such as fixed aeronautical and military radio location services, WiMAX, 4G mobile telecommunication services and WLAN, for example.
  • the first communication device (A) 101 , the second communication device (B) 103 and the third communication device (C) 105 may be, but is not limited to, an ultra-wideband radio communication device, or a WiMedia communication device, for example.
  • the first interferer communication device (D) 111 and the second interferer communication device (E) 113 may be, but is not limited to, a communication device for fixed aeronautical and military radio location services, a WiMAX communication device, a 4G communication device, or a WLAN communication device, for example.
  • the communication system 100 may also be an ad hoc network, for example, in that it does not have centralized control mechanism (i.e., a communication device which functions as a primary (or centralized) controller, such as a base station or an access point, for example).
  • a communication device which functions as a primary (or centralized) controller, such as a base station or an access point, for example.
  • the communication system 100 may be considered as having a distributed control mechanism.
  • Fig. 2 shows a flow diagram 200 describing a method of operating an ultra- wideband radio communication device according to one embodiment of the invention.
  • step 201 the ultra-wideband radio communication device starts processing.
  • step 203 the ultra-wideband radio communication device obtains a measurement of the energy of an interference signal (from an interferer communication device, for example), which is denoted by E M .
  • step 205 it is determined whether or not the energy of the interference signal, EM, is less than a first energy threshold, ETM. If it is determined that the energy of the interference signal, E M , is less than a first energy threshold, ET H I, then the processing proceeds to step 207, where the ultra-wideband radio communication device executes a procedure A. After procedure A is completed, the processing proceeds to step 209, where the ultra-wideband radio communication device ends processing.
  • step 211 it is determined whether or not the energy of the interference signal, E M , is greater than a second energy threshold, E T H2-
  • the second threshold, ETH 2 is greater than the first energy threshold, E T HI.
  • step 213 the ultra-wideband radio communication device executes a procedure B. After procedure B is completed, the processing proceeds to step 209, where the ultra-wideband radio communication device ends processing.
  • step 215 the ultra-wideband radio communication device executes a procedure C.
  • step 209 the ultra-wideband radio communication device ends processing.
  • the method of operating an ultra-wideband radio communication device described above may be used for applications such as detection and avoidance (DAA), for example.
  • procedures B and C may be, for example, two different detection and avoidance (DAA) schemes to be carried out.
  • procedure B may include schemes such as changing (or switching) frequency channels in order to avoid interfering with the operation of the interferer communication device, for example.
  • a mechanism may be desirable in order to enable the said group of ultra-wideband radio communication devices to obtain information on the frequency channel(s) which each ultra-wideband radio communication device may switch to.
  • procedure C may include schemes such as tone nulling, for example.
  • procedure A since procedure A is executed only when the energy of the interference signal is relatively low, procedure A may include schemes such as ignoring the interference signal, for example.
  • the method of operating an ultra-wideband radio communication device also requires a mechanism for enabling a plurality of ultra-wideband radio communication devices to move its operations to the same unused frequency channel.
  • the mechanism may be, but is not limited to, a Channel Consensus (CC) Information Element, for example.
  • CC Channel Consensus
  • Channel Consensus (CC) Information Element may be considered as a channel changing negotiating message. It should also be noted that the Channel Consensus (CC) Information Element may not be considered as a channel change message.
  • a channel change message may be, but is not limited to, a Channel Change Information Element, for example.
  • Figs. 3 (a)-(e) show the contents and the content formats of a Channel Consensus (CC) Information Element according to one embodiment of the invention.
  • the communication device may include a Channel Consensus (CC) Information Element in its beacon, for example, in the next superframe, for example.
  • CC Channel Consensus
  • information element refers to a data structure in a message used by a plurality of communication devices.
  • An illustrative example of an information element is the Channel Consensus (CC) Information Element which will be described in detail shortly.
  • CC Channel Consensus
  • superframe refers to the form or structure which defines how a time interval of a predefined period may be partitioned.
  • a beacon refers to a signal used to provide predetermined control information.
  • a beacon group refers to a group of communication devices which listens to at least one common beacon signal to receive the predetermined control information, so that each communication device in the same beacon group is able to perform the necessary adjustments to maintain communication with other communication devices in the same beacon group.
  • the Channel Consensus (CC) Information Element may then be used by all communication devices within the beacon group which are willing to move their operation to a new unused frequency channel to move to a common unused frequency channel.
  • the Channel Consensus (CC) Information Element is used by a communication device to provide the necessary information (on the available unused frequency channel options the communication device may be able to change to) to the neighboring communication devices in the beacon group, so that a consensus decision may be obtained on which unused frequency channel to change to.
  • Fig. 3(a) shows an example of the Channel Consensus (CC) Information Element 301.
  • the Channel Consensus (CC) Information Element 301 includes an Element Identity field 303 and an Information Element field 305.
  • the Channel Consensus (CC) Information Element 301 may have an element identity number of 26 or 27 or 28, as shown in the Element Identity field 303 of Fig. 3(a), for example.
  • the Information Element field 305 will be discussed in detail in relation to Figs. 3(b) and 3(d).
  • Fig. 3(b) shows a first illustrative example of the Channel Consensus (CC) Information Element 321.
  • the Channel Consensus (CC) Information Element 321 includes an Element Identity field 323, a Length field 325, a Channel Consensus (CC) Control field 327, a Device Address field 329, a plurality of Channel Number fields 331 and a Reserved field 333.
  • the Length field 325 may be used to store the length of the information stored (in terms of octets) in the Channel Consensus (CC) Information Element 321 , starting from the Channel Consensus (CC) Control field 327 to the Reserved field 333.
  • the Channel Consensus (CC) Control field 327 may be used to store control information.
  • An example of the Channel Consensus (CC) Control field 327 will be described in detail in relation to Fig. 3(c).
  • the Device Address field 329 may be used to store the address of the communication device which is making a beacon transmission.
  • the plurality of Channel Number fields 331 may be used to store the status of all the frequency channels in the communication system.
  • channel numbers used in the Channel Consensus (CC) Information Element 321 are based on the WiMedia Physical Layer (PHY) specification version 1.2.
  • frequency channel number 9 refers the frequency channel corresponding to the frequency channel in band group 1 with Time Frequency Code (TFC) 1.
  • this (status) information may also be included in the Channel Number field 331 corresponding to the said frequency channel in the Channel Consensus (CC) Information Element 301 , for example.
  • the Reserved field 333 is typically included in any Information Elements, in order to facilitate further use of the said Information Elements. For example, it may be used for additional functions, e.g. future functions, and is for example unused in one embodiment.
  • Fig. 3(c) shows the Channel Consensus (CC) Control field 327 of the first illustrative example of the Channel Consensus (CC) Information Element 321.
  • the Channel Consensus (CC) Control field 327 includes an Origin (or Owner) bit 343, a Switch bit 345, a Co-located Radio Indication bit 347 and at least one Reserved bit 349.
  • the Origin (or Owner) bit 343 may be set to 1 , for example, if the communication device transmitting the beacon is the originator or initiator of the Channel Consensus (CC) Information Element; otherwise, the Origin (or Owner) bit 343 may be set to 0, for example.
  • CC Channel Consensus
  • the Origin (or Owner) bit 343 may be set to 0, for example, if the communication device transmitting the beacon is the originator or initiator of the Channel Consensus (CC) Information Element; otherwise, the Origin (or Owner) bit 343 may be set to 1 , for example.
  • the Switch bit 345 may be set to 1 , for example, if the communication device transmitting the beacon is able to switch from the currently used frequency channel; otherwise, the Switch bit 345 may be set to 0, for example.
  • the Switch bit 345 may be set to 0, for example, if the communication device transmitting the beacon is able to switch from the currently used frequency channel; otherwise, the Switch bit 345 may be set to 1 , for example.
  • the Co-located Radio Indication bit 347 may be set to 1 , for example, if the presence of an interferer communication device is detected by a co-located Radio (another radio in the same device) or to be a co-located Radio in the currently used frequency channel; otherwise, the Co-located Radio Indication bit 347 may be set to 0, for example.
  • the Co-located Radio Indication bit 347 may be set to 0, for example, if the presence of an interferer communication device is detected by a co-located Radio (another radio in the same device) or to be a co-located Radio in the currently used frequency channel; otherwise, the Co-located Radio Indication bit 347 may be set to 1 , for example.
  • the at least one Reserved bit 349 is typically included in order to facilitate further use. For example, it may be used for additional functions, e.g. future functions, and is for example unused in one embodiment.
  • Fig. 3(d) shows a second illustrative example of the Channel Consensus (CC) Information Element 361.
  • the Channel Consensus (CC) Information Element 361 includes an Element Identity field 363, a Length field 365, a Channel Consensus (CC) Control field 367, a Device Address field 369, a Band Availability field 371 and a Reserved field 373.
  • Channel Consensus (CC) Information Element 361 is similar to the Channel Consensus (CC) Information Element 321 , with the exception of the Band Availability field 371 (of Fig. 3(d)) and the plurality of Channel Number fields 331 (of Fig. 3(b)).
  • the Band Availability field 371 may be used to store information on the availability of frequency bands.
  • An example of the Band Availability field 371 will be described in detail in relation to Fig. 3(e).
  • the Channel Consensus (CC) Information Element 361 may have a smaller value in the Length field 365, as compared to the Channel Consensus (CC) Information Element 321 (of Fig. 3(b)).
  • Fig. 3(e) shows the Band Availability field 371 of the second illustrative example of the Channel Consensus (CC) Information Element 361.
  • the Band Availability field 371 includes a Band 1 bit 383, a Band 2 bit 385, a Band 14 bit 387 and two Reserved bits 389.
  • the arrow 391 is used in this illustration to represent the other Band bits which are not shown, including Band 3 bit, Band 4 bit, Band 5 bit, Band 6 bit, Band 7 bit, Band 8 bit, Band 9 bit, Band 10 bit, Band 11 bit, Band 12 bit and Band 13 bit.
  • the Band 1 bit 383 may be set to 1 , for example, if (frequency) bandi is unused and available for signal transmission with or without tone nulling; otherwise, the Band 1 bit 383 may be set to 0, for example.
  • the Band 1 bit 383 may be set to 0, for example, if (frequency) band 1 is unused and available for signal transmission with or without tone nulling; otherwise, the Band 1 bit 383 may be set to 1 , for example.
  • the (frequency) band numbers used in the Band Availability field 371 are based on the WiMedia Physical Layer (PHY) specification version 1.2.
  • CC Channel Consensus
  • the communication device may include a Channel Consensus (CC) Information Element in its beacon transmission in every superframe starting from the next superframe, for a predetermined number of superframes (after the transmission of its first Channel Consensus (CC) Information Element).
  • CC Channel Consensus
  • the Channel Consensus (CC) Information Element transmitted may include information on the frequency channels which the communication device is able or willing to switch to. This information may be in the form of any one of the two illustrative examples discussed in relation to Figs. 3(b) and 3(d), for example. Further, The Channel Consensus (CC) Information Element transmitted may also include information that the communication device transmitting the beacon is the originator or initiator of the Channel Consensus (CC) Information Element.
  • the communication device which is the originator (or the initiator) of the Channel Consensus (CC) Information Element, waits in one embodiment for the predetermined number of superframes (after transmitting its first Channel Consensus (CC) Information Element) in order receive all the response Channel Consensus (CC) Information Elements from its neighboring communication devices, before making the decision on which frequency channel to switch to.
  • the decision made on frequency channel to switch to may be observed in the Channel Change Information Element transmitted by the communication device (which is the originator (or the initiator) of the Channel Consensus (CC) Information Element) subsequently.
  • the communication device which is the originator (or the initiator) of the Channel Consensus (CC) Information Element, makes the decision on which frequency channel to switch to.
  • the communication device which is the originator (or the initiator) of the Channel Consensus (CC) Information Element, only considers the information from the last received Channel Consensus (CC) Information Element from any neighboring communication device when making the decision on which frequency channel to switch to. Further, it should be noted that neighboring communication devices which are not willing to switch are in one embodiment not considered during the above mentioned decision making process.
  • a communication device Upon receiving a Channel Consensus (CC) Information Element, a communication device, which is not the originator (or the initiator) of the Channel Consensus (CC) Information Element, for example transmits a response Channel Consensus (CC) Information Element in the next superframe.
  • the response Channel Consensus (CC) Information Element transmitted for example includes information on the frequency channels which the communication device is able or willing to switch to, as well as information that it is not the originator of the Channel Consensus (CC) Information Element.
  • CC Channel Consensus
  • a communication device may not transmit a Channel Consensus (CC) Information Element, which includes information that the communication device transmitting the beacon is the originator or initiator of the Channel Consensus (CC) Information Element, for a predetermined number of superframes, if it had first received a Channel Consensus (CC) Information Element, which includes information that another communication device is the originator or initiator of the Channel Consensus (CC) Information Element.
  • the communication device may only transmit a Channel Consensus (CC) Information Element, which includes information that the communication device transmitting the beacon is not the originator or initiator of the Channel Consensus (CC) Information Element.
  • a communication device which had included information that it is the originator or initiator of the Channel Consensus (CC) Information Element transmitted in the preceding superframe
  • receives a Channel Consensus (CC) Information Element which includes information that another communication device is the originator or initiator of the Channel Consensus (CC) Information Element
  • the communication device may transmit a Channel Consensus (CC) Information Element, which includes information that the communication device transmitting the beacon is the originator or initiator of the Channel Consensus (CC) Information Element, if its beacon slot number is less than that of the other communication device which had sent the Channel Consensus (CC) Information Element.
  • the communication device may not transmit a Channel Consensus (CC) Information Element, which includes information that the communication device transmitting the beacon is the originator or initiator of the Channel Consensus (CC) Information Element, for the predetermined number of superframes.
  • CC Channel Consensus
  • a communication device which transmits a response Channel Consensus (CC) Information Element (i.e., which includes information that the communication device transmitting the beacon is not the originator or initiator of the Channel Consensus (CC) Information Element), may not include information on any frequency channel (or band) which was not included on the last received Channel Consensus (CC) Information Element.
  • CC Channel Consensus
  • the communication device may not transmit a Channel Consensus Information Element for a predefined duration, as defined in the received Channel Change Information Element.
  • a communication device may only transmit its response Channel Consensus (CC) Information Element, which includes information on the frequency channel (or band) which it is switching to as included in its Channel Change Information Element.
  • CC Channel Consensus
  • a communication device which receives a Channel Consensus (CC) Information Element after it had earlier transmitted a Channel Change Information Element may not respond with any Channel Consensus Information Element until a channel change.
  • a communication device may wait until a channel change is completed before initiating a Channel Consensus (CC) Information Element transmission.
  • the communication device may initiate a Channel Change Information Element transmission, if it receives a Channel Change Information Element.
  • FIG. 4 The flow diagram of one embodiment of another method of operating an ultra- wideband radio communication device, in which at least one of the above mentioned guidelines is used, is shown in Fig. 4.
  • Fig. 4 shows a flow diagram 400 of another method of operating an ultra- wideband radio communication device, according to one embodiment of the invention.
  • step 401 the ultra-wideband radio communication device starts processing.
  • the ultra-wideband radio communication device already knows that it is required to switch to another frequency channel (for example, as part of a detection and avoidance (DAA) scheme).
  • DAA detection and avoidance
  • the ultra-wideband radio communication device is the midst of a large file transfer, for example, it may be advantageous for the group of ultra- wideband radio communication devices involved in the large file transfer to be able to select one frequency channel which they could all switch to, in order to continue with the large file transfer.
  • a counter representing the number of time intervals during which the ultra-wideband radio communication device has waited for a response message to the transmitted channel changing negotiation messages is first reset to 0. Subsequently, this counter will be referred to as the number of time intervals counter.
  • the ultra-wideband radio communication device transmits a channel changing negotiation message.
  • the channel changing negotiation message may include information such as which frequency channels the ultra-wideband radio communication device may switch to.
  • the channel changing negotiation message may also include information indicating that the said ultra-wideband radio communication device is the initiator of the information exchange process, for example.
  • a channel changing negotiation message may be, but is not limited to, a Channel Consensus Information Element, for example.
  • the ultra-wideband radio communication device receives a response message to its transmitted channel changing negotiation message.
  • the response message may include information on the frequency channels which the other ultra-wideband radio communication device may switch to. This information on the frequency channels which the other ultra-wideband radio communication device may switch to, may not include all the frequency channels which the other ultra-wideband radio communication device may switch to, but may include only those frequency channels which the ultra- wideband radio communication device may switch to as well (as indicated in the channel changing negotiation message).
  • step 409 the number of time intervals counter is incremented by 1.
  • step 411 it is determined whether or not the number of time intervals counter has reached (or is equal to) a predefined number of time intervals to wait, N.
  • the predefined number of time intervals to wait, N may represent the number of time intervals after which the ultra-wideband radio communication device makes a decision to select a frequency channel to switch to, for example.
  • the predefined number of time intervals to wait, N may also represent the number of response messages which the ultra- wideband radio communication device may receive before making the decision to select a frequency channel to switch to, for example.
  • step 405 the ultra-wideband radio communication device transmits another channel changing negotiation message.
  • step 4111 if it is determined (in step 411) that the number of time intervals counter is not equal to the predefined number of time intervals to wait, N, the processing may proceed to step 407 instead, where the ultra-wideband radio communication device continues waiting to receive the next response message.
  • the ultra-wideband radio communication device may transmit only one channel changing negotiation message in this alternative implementation, whereas the ultra-wideband radio communication device may transmit more than one channel changing negotiation message in the earlier discussed implementation.
  • step 413 the ultra-wideband radio communication device makes a decision to select the frequency channel to switch to.
  • step 415 the ultra-wideband radio communication device ends processing.
  • step 415 only ends the information exchange process.
  • the ultra-wideband radio communication device may transmit a channel change message (to indicate that it is switching to the selected frequency channel), for example.
  • Fig. 5 shows a table 500 used in the illustration of a first criterion for determining which frequency channel to switch to, according to one embodiment of the invention.
  • a first criterion for determining which frequency channel to switch to may be to select the available frequency channel, which has the lowest frequency channel number and which has the smallest absolute frequency channel number difference from the frequency channel number of the currently used frequency channel.
  • a communication device (labeled Originator) 501 which is currently operating in the frequency channel with frequency channel number 10, detects the presence of an interferer communication device.
  • the communication device (Originator) 501 then initiates a Channel Consensus (CC) Information Element transmission and receives all the response Channel Consensus (CC) Information Elements from its neighboring communication devices within the predetermined number of superframes.
  • the information from all the Channel Consensus (CC) Information Elements may be tabulated as shown in the table 500.
  • the frequency channel with frequency channel number 13 (503) is the available frequency channel which has the lowest frequency channel number.
  • the absolute frequency channel number difference from the frequency channel number of the currently used frequency channel is 3 for the frequency channel with frequency channel number 13 (503) and 104 for the frequency channel with frequency channel number 114 (505), respectively. Therefore, the available frequency channel which has the smallest absolute frequency channel number difference from the frequency channel number of the currently used frequency channel is the frequency channel with frequency channel number 13 (503) as well.
  • the frequency channel selected may be the frequency channel with frequency channel number 13 (503).
  • the communication device (Originator) 501 may switch to a frequency channel available to the communication device (Originator) 501.
  • the communication device (Originator) 501 may also go into hibernation (or into an inactive mode).
  • Fig. 6 shows a table 600 used in the illustration of a second criterion for determining which frequency channel to switch to, according to one embodiment of the invention.
  • a second criterion for determining which frequency channel to switch to may be to map the set of physical frequency channel numbers to a set of logical frequency channel numbers and then select the available frequency channel, which has the lowest logical frequency channel number and which has the smallest absolute logical frequency channel number difference from the logical frequency channel number of the currently used frequency channel.
  • the mapping to the set of logical frequency channel numbers may be performed such that the physical frequency channels corresponding to a band group are mapped to a contiguous set of logical frequency channel numbers.
  • the physical frequency channel numbers are first mapped to the respective logical frequency channel numbers, as shown in the table 600.
  • the frequency channel with the physical frequency number 9 (601 ) may have the logical frequency channel number 1
  • the frequency channel with the physical frequency number 72 (603) may have the logical frequency channel number 8.
  • a communication device (labeled Originator) 613, which is currently operating in the frequency channel with logical frequency channel number 1 (601), detects the presence of an interferer communication device.
  • the communication device (Originator) 613 then initiates a Channel
  • Consensus Information Element transmission and receives all the response Channel Consensus (CC) Information Elements from its neighboring communication devices within the predetermined number of superframes.
  • the information from all the Channel Consensus (CC) Information Elements may be tabulated as shown in the table 600.
  • the frequency channel with frequency channel number 9 is the available frequency channel which has the lowest logical frequency channel number.
  • the absolute logical frequency channel number difference from the logical frequency channel number of the currently used frequency channel is 8 for the frequency channel with logical frequency channel number 9 (605) and 53 for the frequency channel with logical frequency channel number 54 (611 ), respectively. Therefore, the available frequency channel which has the smallest absolute logical frequency channel number difference from the logical frequency channel number of the currently used frequency channel is the frequency channel with logical frequency channel number 9 (605).
  • the frequency channel selected should be the frequency channel with logical frequency channel number 9 (605).
  • the logical frequency channel numbers may be arranged such that the frequency channels which use Time Frequency Codes (TFC) may have a lower logical frequency number than the frequency channels which use Fixed Frequency Interleaving (FFI) modes within a band group, for example.
  • TFC Time Frequency Codes
  • FFI Fixed Frequency Interleaving
  • the communication device (Originator) 613 should switch to a frequency channel available to the communication device (Originator) 613.
  • the communication device (Originator) 613 may also go into hibernation (or into an inactive mode).
  • Figs. 7 (a)-(c) show three tables used in the illustration of a third criterion for determining which frequency channel to switch to, according to one embodiment of the invention.
  • a third criterion for determining which frequency channel to switch to may be to select the frequency channel using the largest number of available (frequency) bands in the band group which has the largest number of available (frequency) bands and which has the smallest absolute band group number difference from the band group number of the band group in which the currently used frequency channel is operating.
  • (frequency) bands in the band group may be given priority over the band group which has a fewer available (frequency) bands but which has the smallest absolute band group number difference from the band group number of the band group in which the currently used frequency channel is operating.
  • a communication device (labeled Originator) 701 which is currently operating in the frequency channel with frequency channel number 9, detects the presence of an interferer communication device in (frequency) band 2.
  • the communication device (Originator) 701 then initiates a Channel Consensus (CC) Information Element transmission and receives all the response Channel Consensus (CC) Information Elements from its neighboring communication devices within the predetermined number of superframes.
  • CC Channel Consensus
  • CC Channel Consensus Information Elements from its neighboring communication devices within the predetermined number of superframes.
  • the information from all the Channel Consensus (CC) Information Elements may be tabulated as shown in the table 700.
  • the relationship between the frequency channel numbers, the (frequency) band numbers and the band group numbers used in this example are based on the WiMedia Physical Layer (PHY) specification version 1.2.
  • a table 720 which shows the relationship between the band group numbers and the available (frequency) band numbers, may be obtained.
  • a table 740 which shows the relationship between the frequency channel numbers and the (frequency) band numbers, may also be obtained.
  • the currently used frequency channel uses the (frequency) band with band number 1 , the (frequency) band with band number 2 and the (frequency) band with band number 3. Since it is known that the (frequency) band with band number 1 , the (frequency) band with band number 2 and the (frequency) band with band number 3 are all in band group 1 , then the band group in which the currently used frequency channel is operating is band group 1.
  • band group 1 which is also the band group corresponding to the currently used frequency channel.
  • the frequency channel with frequency channel number 11 (row 743) and the frequency channel with frequency channel number 73 (row 745) are operating in band group 1. It can also be seen that the frequency channel with frequency channel number 11 (row 743) uses only 1 (frequency) band, while the frequency channel with frequency channel number 73 (row 745) uses 2 (frequency) bands.
  • the frequency channel selected should be the frequency channel with frequency channel number 73 (745).
  • the communication device (Originator) 701 may switch to a frequency channel available to the communication device (Originator) 701.
  • the frequency channel number may be a physical one or a logical one.
  • Figs. 8 (a)-(b) show a flow diagram 800 of an exemplary illustration of how one embodiment of the invention may be implemented.
  • step 801 the communication device starts processing.
  • step 803 the communication device first checks whether or not it has received a Channel Consensus (CC) Information Element.
  • CC Channel Consensus
  • step 805 the energy of interference signal(s) in the current operating frequency channel is measured in the next time interval.
  • step 807 the processing proceeds to step 807, where the communication device responds by transmitting a response Channel Consensus (CC) Information Element in the next time interval.
  • the response Channel Consensus (CC) Information Element may include information on the frequency channels (or frequency bands) which the said communication device may switch to. As mentioned earlier, this information on the frequency channels which the said communication device may switch to, may not include all the frequency channels which the said communication device may switch to, but may include only those frequency channels which the other communication device(s) may switch to as well, as indicated in the received Channel Consensus (CC) Information Element.
  • step 805 the energy of interference signal(s) in the current operating frequency channel is measured.
  • step 805 the processing proceeds to step 809, where it is determined whether or not the measured energy of interference signal is greater than a first energy threshold of, say, X dBm, for example.
  • step 809 If it is determined in step 809 that the measured energy of interference signal is not greater than the first energy threshold, then the processing proceeds to step 811 , where it is determined whether or not the measured energy of interference signal is greater than a second energy threshold of, say, Y dBm, for example.
  • the value of X is in the range from about -55dBm to about -1OdBm and wherein the value of Y is in the range from about -8OdBm to about -55dBm. In another embodiment, the value of X is about -45dBm and wherein the value of Y is about -6OdBm.
  • step 811 If it is determined in step 811 that the measured energy of interference signal is not greater than the second energy threshold, then the processing proceeds to step 819.
  • step 811 if it is determined in step 811 that the measured energy of interference signal is greater than the second energy threshold, then the processing proceeds to step 813.
  • step 813 a procedure of tone nulling is carried out for the frequency bands affected by the interference signal(s).
  • the procedure of tone nulling may be initiated by the communication device, by transmitting a Tone Nulling Information Element, for example. Further, it should be noted that the procedure of tone nulling may be only carried out if there is no intention of switching to another frequency channel at that time.
  • step 809 if it is determined that the measured energy of interference signal is greater than the first energy threshold, then the processing proceeds to step 815, where it is determined whether or not the measured energy of interference signal has been greater than the first energy threshold for a predetermined duration (mCCIEInitiate superframes, for example).
  • step 815 if it is determined that the measured energy of interference signal has not been greater than the first energy threshold for the predetermined duration, then the processing returns to step 803 again.
  • step 817 it is determined whether or not the communication device has received a Channel Consensus (CC) Information Element for the predetermined duration, or whether or not a channel change is pending in the beacon group.
  • CC Channel Consensus
  • the determination of whether or not the communication device has received a Channel Consensus (CC) Information Element for the predetermined duration, or whether or not a channel change is pending in the beacon group will only yield a "NO" result in the case where a channel change is not pending and where the communication device has not received a Channel Consensus (CC) Information Element for the predetermined duration. Otherwise, the determination of whether or not the communication device has received a Channel Consensus (CC) Information Element for the predetermined duration, or whether or not a channel change is pending in the beacon group, will yield a "YES" result, in all other cases.
  • CC Channel Consensus
  • step 817 If a "YES" result is determined in step 817, the processing proceeds to step 819, where it is determined whether or not a channel change is pending in the next time interval.
  • the time interval may be, but is not limited to, a superframe, for example.
  • step 817 the processing proceeds to step 821 , where the communication device transmits a Channel Consensus (CC) Information Element.
  • the Channel Consensus (CC) Information Element may include information such as which frequency channels which the communication device may switch to, and information indicating that the said communication device is the initiator of the Channel Consensus (CC) Information Element.
  • step 823 the communication device continues to transmit subsequent Channel Consensus (CC) Information Elements for the predetermined number of time intervals.
  • the subsequent Channel Consensus (CC) Information Elements may include information on the frequency channels which neighboring communication devices and itself may switch to. The information on the frequency channels which neighboring communication devices may switch to may be included in the response Channel Consensus (CC) Information Elements received within the predetermined number of time intervals.
  • step 825 the communication device selects the frequency channel to switch to based on the information on the frequency channels which all (or most of) neighboring communication devices and itself may switch to.
  • the communication device then switches to the selected frequency channel.
  • the communication device may also power off or go into a sleep mode (or hibernate).
  • step 819 if it is determined that a channel change is not pending in the next time interval, the processing returns to step 803.
  • step 827 the communication device switches to an unused frequency channel in the next time interval, if needed.
  • the processing returns to step 805.
  • the first illustrative example shows how the communication devices A (101), B (103) and C (105) may arrive at the selection of the same frequency channel to switch to, based on the first criterion, when the presence of interferer communication devices D (111 ) and E (113) are detected (at about the same time).
  • the communication device A (101 ) then transmits a Channel Consensus (CC) Information Element (as initiator) with the information that it is willing to switch to the frequency channel with frequency channel number 13, the frequency channel with frequency channel number 15 or the frequency channel with frequency channel number 73.
  • CC Channel Consensus
  • the communication device B (103) transmits a response Channel Consensus (CC) Information Element with the information that it is willing to switch to the frequency channel with frequency channel number 13, the frequency channel with frequency channel number 15 or the frequency channel with frequency channel number 73
  • the communication device C (105) transmits a Channel Consensus (CC) Information Element (as initiator) with the information that it is willing to switch to the frequency channel with frequency channel number 13, or the frequency channel with frequency channel number 14.
  • CC Channel Consensus
  • the communication device A in one embodiment transmits a Channel Consensus (CC) Information Element (as initiator) with the information that it is willing to switch to the frequency channel with frequency channel number 13, the frequency channel with frequency channel number 15 or the frequency channel with frequency channel number 73.
  • the communication device B (103) may transmit a response Channel Consensus (CC) Information Element with the information that it is willing to switch to the frequency channel with frequency channel number 13 only (in view of the Channel Consensus (CC) Information Element transmitted by the communication device C (105) in the previous superframe).
  • the communication device C (105) may transmit a Channel Consensus (CC) Information Element (as initiator) with the information that it is willing to switch to the frequency channel with frequency channel number 13 only (in view of the Channel Consensus (CC) Information Element transmitted by the communication device B (103) in the previous superframe).
  • CC Channel Consensus
  • the communication device A (101) may transmit a Channel Consensus (CC) Information Element (as initiator) with the information that it is willing to switch to the frequency channel with frequency channel number 13 only (in view of the Channel Consensus (CC) Information Element transmitted by the communication device B (103) in the previous superframe).
  • the communication device B (103) may transmit a response Channel Consensus (CC) Information Element with the information that it is willing to switch to the frequency channel with frequency channel number 13 only and the communication devices C (105) would transmit a Channel Consensus (CC) Information Element (as initiator) with the information that it is willing to switch to the frequency channel with frequency channel number 13 only.
  • the above transmissions may continue for a predetermined number of superframes, after which the communication device A (101 ) may make the decision to select the frequency channel with frequency channel number 13 as the frequency channel to switch to. Then, the communication device A (101) may initiate a Channel Change Information Element to switch to the frequency channel with frequency channel number 13.
  • the communication devices B (103) and C (105) may also initiate a Channel Change Information Element to switch to the frequency channel with frequency channel number 13.
  • the second illustrative example shows how the communication devices A (101), B (103) and C (105) may arrive at the selection of the same frequency channel to switch to, based on the first criterion, when the presence of interferer communication devices D (111 ) and E (113) are detected (at different times).
  • the communication device A (101 ) initiates a
  • the communication device C (105) detects the presence of the interferer communication device E (113) in the frequency channel with frequency channel number 73.
  • the communication device B (103) initiates a Channel Change Information Element to switch to the frequency channel with frequency channel number 73.
  • the communication device C (105) transmits a Channel Consensus (CC) Information Element (as initiator) with the information that it is willing to switch to the frequency channel with frequency channel number 13, and the frequency channel with frequency channel number 14.
  • CC Channel Consensus
  • the communication device C (105) when the communication device C (105) discovers the Channel Change Information Element to switch to the frequency channel with frequency channel number 73 transmitted by the communication device B (103), it may refrain from transmitting any further Channel Consensus (CC) Information Element. Instead, the communication device C (105) may initiate a Channel Change Information Element to switch to the frequency channel with frequency channel number 73 as well.
  • CC Channel Consensus
  • the communication device C (105) may then transmit a Channel Consensus (CC) Information Element (as initiator) with the information that it is willing to switch to the frequency channel with frequency channel number 13, or the frequency channel with frequency channel number 14.
  • CC Channel Consensus
  • the communication device B (103) may transmit a response Channel Consensus (CC) Information Element with the information that it is willing to switch to the frequency channel with frequency channel number 13 only (in view that it was willing to switch to the frequency channel with frequency channel number 13, the frequency channel with frequency channel number 15 and the frequency channel with frequency channel number 73).
  • CC Channel Consensus
  • the communication device C (105) may transmit a Channel Consensus (CC) Information Element (as initiator) with the information that it is willing to switch to the frequency channel with frequency channel number 13 only (in view of the Channel Consensus (CC) Information Element transmitted by the communication device B (103) in the previous superframe).
  • the communication device B (103) may transmit a response Channel Consensus (CC) Information Element with the information that it is willing to switch to the frequency channel with frequency channel number 13 only.
  • the above transmissions may continue for a predetermined number of superframes, after which the communication device C (105) may make the decision to select the frequency channel with frequency channel number 13 as the frequency channel to switch to. Then, the communication device C (105) may initiate a Channel Change Information Element to switch to the frequency channel with frequency channel number 13.
  • the communication device B (103) may also initiate a Channel Change Information Element to switch to the frequency channel with frequency channel number 13.
  • the communication device A (101 ) may also initiate a Channel Change Information Element to switch to the frequency channel with frequency channel number 13.
  • a communication device which is the initiator of the Channel Consensus (CC) Information Element, decides to switch to a frequency channel, it may include the Channel Change Information Element in its beacon in the next superframe. Further, a neighboring communication device which receives the Change Channel Information Element, may include a Change Channel Information Element in its beacon in the following superframe, if it is willing to switch to the said frequency channel.
  • CC Channel Consensus
  • a conventional channel change procedure may be, but is not limited to, the WiMedia MAC version 1.2 channel change procedure, for example.
  • a communication device may not scan the frequency channels (or the (frequency) bands) at all the time.
  • a communication device may scan all (frequency) bands, for example, when it receives a Channel Consensus (CC) Information Element, or when it detects the presence of an interferer communication device in its current frequency channel.
  • CC Channel Consensus
  • a communication device should scan the (frequency) bands in the band group, in which its current frequency channel is operating, all the time.
  • beacon transmissions may also be affected by interference, for example, and the Channel Consensus (CC) Information Element may not be transmitted reliably using beacons.
  • CC Channel Consensus
  • the following may be used for exchanging control information, including the Channel Consensus (CC) Information Element, namely, selected tones in the (frequency) band used for operation (or signal transmission), a selected (frequency) band in a band group (for example, (frequency) band with band number 13 in band group 5), selected tones in (frequency) band with band number 13 in band group 5, selected tones in one of (frequency) band with band number 1 , (frequency) band with band number 2 or (frequency) band with band number 3 in band group 1 , for example.
  • CC Channel Consensus
  • two parallel radio frequency channels may be used, one for data transmission and one for control, including control signal exchanges such as with the Channel Consensus (CC) Information Element, for example.
  • CC Channel Consensus
  • each communication device is required to always listen to the control channel.
  • An option for transmitting and receiving signals in the control channel may, but is not limited to, Prioritized Content Access (PCA) of WiMedia, for example.
  • PCA Prioritized Content Access
  • An alternative approach may be to allow each communication device to broadcast periodically in the control channel and/or the frequency channel of operation.
  • Embodiments of the invention may have the following effects.
  • Embodiments of the invention may provide a means for determining a frequency channel which a group of communication devices may switch to. With such a means, it is now possible for the said group of communication devices to maintain a communication connection among themselves before and after switching to the new frequency channel, for example. This is particularly advantageous in a scenario when there is a large data file being transferred from one communication device to another within the said group of communication devices, when the need to switching frequency channels arises, for example.

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Abstract

La présente invention concerne un procédé pour le fonctionnement d'un dispositif de radiocommunications ultra large bande. Le procédé comprend la génération d'un message de négociation de changement de canal renfermant des informations relatives à au moins un canal de fréquences que le dispositif de radiocommunications ultra large bande souhaite changer. Le procédé selon l'invention comprend également la transmission du message de négociation de changement de canal à au moins un autre dispositif de radiocommunications ultra large bande avec lequel le dispositif de radiocommunications ultra large bande a établi une connexion de communication dans un canal de fréquences actuel. Selon le procédé de l'invention, le dispositif de radiocommunications ultra large bande peut recevoir des messages de négociation de changement de canal provenant de l'autre dispositif de radiocommunications ultra large bande, les messages de négociation de changement de canal comprenant des informations relatives à au moins un canal de fréquences que l'autre dispositif de radiocommunications ultra large bande souhaite changer. Le dispositif de radiocommunications ultra large bande peut déterminer si le dispositif de radiocommunications ultra bande large est capable de changer le canal de fréquences compris dans le message de négociation de changement de canal, et générer un autre message de négociation de changement de canal renfermant des informations relatives à au moins un canal de fréquences que le dispositif de radiocommunications ultra large bande souhaite changer. Le dispositif de radiocommunications ultra large bande peut ensuite transmettre l'autre message de négociation de changement de canal à l'autre dispositif de radiocommunications ultra large bande. Après un intervalle prédéterminé, le dispositif de radiocommunications ultra large bande peut sélectionner, en fonction d'un critère prédéterminé, le canal de fréquences qu'il faut changer, lorsque le dispositif de radiocommunications ultra large bande est l'initiateur du changement de canal de fréquences souhaité.
PCT/SG2008/000113 2007-04-09 2008-04-09 Procédé pour le fonctionnement d'un dispositif de radiocommunications ultra large bande Ceased WO2008123834A1 (fr)

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