Abstract: To facilitate multi-channel communications over distributed-control radio networks, the timing of networks on multiple substantially independent channels are adjusted (350) so as to establish a common time base among the networks. With this common time base, data is transmitted concurrently (230), using the bandwidth provided by the multiple networks. To further optimize the efficiency of this technique for cognitive radio networks, the quiet period (QP) and signaling window (SW) on each network are scheduled (355) to provide overlapping quiet periods (QP) and/or overlapping signaling windows (SW). Preferably, each multi-channel user is assigned (360) the same time slot in the beacon periods (210) of the network on each channel, thereby facilitating efficient beacon transmission and reception.

Abstract: A method for dynamically reconfiguring a regulation-compliance mode of a device, belonging to a wireless network and operating under a network-operation mode (311, 321, 322) in a spectrum band with primary users. The method includes periodically determining at least one of: a primary protection capability of the device (501, 502, 704, 705), availability of enabling signal to the device (601, 701), and a frequency of location change of the device (508, 510, 711, 712); and based on the results of such determinations, operating and configuring transmission parameters of the device according to one of a plurality of regulation-compliance modes that are supported by the device.

Abstract: In a distributed-control cognitive radio network, each secondary user (200) in a network broadcasts parameters (125) that indicate the minimum quiet-period sensing demand for regular quiet-periods that the device requires for reliable detection of a primary user (290). Each device (200) in the network adjusts its quiet-period sensing rate to accommodate the highest minimum sensing demand (155, 160), thereby providing optimal efficiency relative to quiet-period support while assuring that all devices (200) in the network are provided at least their minimum quiet-period sensing demand (150). Both the interval between regular quiet-periods and the duration of these quiet-periods are negotiated among the devices on the network (155). A quiet-period index (140) is used to synchronize all of the devices to a common time base. Techniques are also provided for efficient coordination of on-demand quiet-period requests, and for supporting different quiet-period schedules for multiple classes of primary users.

Abstract: A flexible wireless system and method that support both centralized and distributed modes of MAC protocols, use a new recurring MAC superframe comprising: a beacon period, a data/sense/sleep period for data selective communication, sleep and channel sensing for detecting primary users in cognitive systems; and a signaling window used for exchanging network entry messages and channel reservation requests, the system including beacon operation, a peer beacon device in distributed mode and a master beacon device in centralized mode which are used to selectively participate in the beacon operation, as well as a slave beacon device associated with the master device. The system may employ controlled channel access for the beacon period, the channel access being reservation based. The invention provides a unified MAC protocol that can be adopted in the standards, and supports flexible operation in distributed mode or centralized mode, and seamless transfer from one to the other.

Abstract: A source-assisted channel management method in a distributed spectrum cognitive radio wireless network handling a source of multimedia stream data handles a plurality of communicating devices (1, 2, 3) forming a group, and manages channels with no separate controller that is referenced in applicable IEEE standard. The source makes the reservation on behalf of the device group knows traffic schedule, and determines out-of-band channel scanning, back up channel and channel vacation. The method uses a flexible MAC superframe structure and proactively scans for back-up channels which could be used in lieu of the current channel, identifies devices in the group which should vacate a current channel when any one device from the group of communicating devices (1, 2, 3) detects an incumbent, and make a determination as to when the wireless network should vacate the current channel based on said traffic schedule. The method ensures that no interference is caused to existing users and maintains QoS.

Abstract: A system includes a first primary wireless system (120) that communicates over a first range, and a first beaconing device (130) associated with the first primary wireless system (120). The first beaconing device (130) communicates over at least at a second range, wherein the second range is greater than the first range. The first beaconing device listens for beacons (510) from other beaconing devices (130) associated with other primary wireless systems (120) on a plurality of channels over which the other primary systems may operate. After listening for beacons from the other beaconing devices (130) associated with other primary wireless systems, the first beaconing device transmits a first beacon (510) to a wireless device (114) of a secondary wireless system (110) that may communicate over the second range. The first beacon includes data indicating an occupation of a first one of the channels by the first primary wireless system (120).

Abstract: A system (400), apparatus (300), and method (100) are provided to synchronize distributed (otherwise uncoordinated) networks (400) of independent nodes (401i). Such synchronization can be used in a number of different ways. In the context of cognitive radios, such synchronization can be used to synchronize quiet periods. Quiet periods are times when all cognitive radios (that are otherwise uncoordinated) become quiet so that incumbent users can be detected reliably. The technique of the present invention converges quickly and scales well.

Abstract: A network information apparatus (400), system (100) (200) and method for distributing network information in a multi-channel (MC) wireless network (100) (200), comprising a network information module (400) that implements inter-channel communication of network information in an MC network according to a pre-determined network information sharing procedure and keeping an own cache (401) of each node refreshed and free of out-of-date information, and, for an active proxy-based sharing procedure thereof only, adapting to changes in node/channel associations, suppressing duplicate inter-channel information, and synchronizing own clocks (404) of each node.

Abstract: A method for dynamically reconfiguring a regulation-compliance mode of a device, belonging to a wireless network and operating under a network-operation mode (311, 321, 322) in a spectrum band with primary users. The method includes periodically determining at least one of: a primary protection capability of the device (501, 502, 704, 705), availability of enabling signal to the device (601, 701), and a frequency of location change of the device (508, 510, 711, 712); and based on the results of such determinations, operating and configuring transmission parameters of the device according to one of a plurality of regulation-compliance modes that are supported by the device.

Abstract: The present invention is a system (1200), base station (1100)/customer premise equipment (1150) apparatus, and method (400 450) for a two-stage quiet-period management mechanism that provides the required protection to incumbents (primary spectrum users) while supporting the desired QoS of secondary users participating in a cognitive radio network. In the first stage, a simple fast sensing (301) is done (e.g., energy detection) by all devices in the network. Depending on the result of the fast sensing, the second and possibly longer stage, herein termed fine sensing (302), is performed.

Abstract: To facilitate multi-channel communications over distributed-control radio networks, the timing of networks on multiple substantially independent channels are adjusted (350) so as to establish a common time base among the networks. With this common time base, data is transmitted concurrently (230), using the bandwidth provided by the multiple networks. To further optimize the efficiency of this technique for cognitive radio networks, the quiet period (QP) and signaling window (SW) on each network are scheduled (355) to provide overlapping quiet periods (QP) and/or overlapping signaling windows (SW). Preferably, each multi-channel user is assigned (360) the same time slot in the beacon periods (210) of the network on each channel, thereby facilitating efficient beacon transmission and reception.

Abstract: A source-assisted channel management method in a distributed spectrum cognitive radio wireless network handling a source of multimedia stream data handles a plurality of communicating devices (1, 2, 3) forming a group, and manages channels with no separate controller that is referenced in applicable IEEE standard. The source makes the reservation on behalf of the device group knows traffic schedule, and determines out-of-band channel scanning, back up channel and channel vacation. The method uses a flexible MAC superframe structure and proactively scans for back-up channels which could be used in lieu of the current channel, identifies devices in the group which should vacate a current channel when any one device from the group of communicating devices (1, 2, 3) detects an incumbent, and make a determination as to when the wireless network should vacate the current channel based on said traffic schedule. The method ensures that no interference is caused to existing users and maintains QoS.

Abstract: A flexible wireless system and method that support both centralized and distributed modes of MAC protocols, use a new recurring MAC superframe (m) comprising: a beacon period (BP), a data/sense/sleep period (DSSP) for data selective communication, sleep and channel sensing for detecting primary users in cognitive systems; and a signaling window (SW) used for exchanging network entry messages and channel reservation requests, the system including beacon operation, a peer beacon device in distributed mode and a master beacon device in centralized mode which are used to selectively participate in the beacon operation, as well as a slave beacon device associated with the master device. The system may employ controlled channel access for the beacon period, the channel access being reservation based. The invention provides a unified MAC protocol that can be adopted in the standards, and supports flexible operation in distributed mode or centralized mode, and seamless transfer from one to the other.

Abstract: In a distributed-control cognitive radio network, each secondary user (200) in a network broadcasts parameters (125) that indicate the minimum quiet-period sensing demand for regular quiet-periods that the device requires for reliable detection of a primary user (290). Each device (200) in the network adjusts its quiet-period sensing rate to accommodate the highest minimum sensing demand (155, 160), thereby providing optimal efficiency relative to quiet-period support while assuring that all devices (200) in the network are provided at least their minimum quiet-period sensing demand (150). Both the interval between regular quiet-periods and the duration of these quiet-periods are negotiated among the devices on the network (155). A quiet-period index (140) is used to synchronize all of the devices to a common time base. Techniques are also provided for efficient coordination of on-demand quiet-period requests, and for supporting different quiet-period schedules for multiple classes of primary users.

Abstract: A system includes a first primary wireless system (120) that communicates over a first range, and a first beaconing device (130) associated with the first primary wireless system (120). The first beaconing device (130) communicates over at least at a second range, wherein the second range is greater than the first range. The first beaconing device listens for beacons (510) from other beaconing devices (130) associated with other primary wireless systems (120) on a plurality of channels over which the other primary systems may operate. After listening for beacons from the other beaconing devices (130) associated with other primary wireless systems, the first beaconing device transmits a first beacon (510) to a wireless device (114) of a secondary wireless system (110) that may communicate over the second range. The first beacon includes data indicating an occupation of a first one of the channels by the first primary wireless system (120).

Abstract: A network information apparatus (400), system (100) (200) and method for distributing network information in a multi-channel (MC) wireless network (100) (200), comprising a network information module (400) that implements inter-channel communication of network information in an MC network according to a pre-determined network information sharing procedure and keeping an own cache (401) of each node refreshed and free of out-of-date information, and, for an active proxy-based sharing procedure thereof only, adapting to changes in node/channel associations, suppressing duplicate inter-channel information, and synchronizing own clocks (404) of each node.

Abstract: A system (400), apparatus (300), and method (100) are provided to synchronize distributed (otherwise uncoordinated) networks (400) of independent nodes (401i). Such synchronization can be used in a number of different ways. In the context of cognitive radios, such synchronization can be used to synchronize quiet periods. Quiet periods are times when all cognitive radios (that are otherwise uncoordinated) become quiet so that incumbent users can be detected reliably. The technique of the present invention converges quickly and scales well.

Abstract: A method and apparatus for determining a period for transmitting a video stream comprising a plurality of base layers (110) and corresponding enhancement layers (115) is disclosed. The method comprises the steps of obtaining a measure of channel condition, transmitting each of said base layers (110) for a predetermined time period and transmitting a corresponding enhancement layer (115) for a period determined based on said measure of channel condition and said base layer time period. In one aspect of the invention, the base layer time period and the enhancement layer period are less than a critical time period.

Abstract: A method and apparatus for transcoding macroblocks of a high definition television signal to co-sited macroblocks of a standard definition television signal wherein SD macroblocks are derived directly from co-sited HD macroblocks, i.e. without having to compute the SD macroblock information from its corresponding SD image sequence.

Abstract: A method and apparatus for transcoding macroblocks of a high definition television signal to co-sited macroblocks of a standard definition television signal wherein SD macroblocks are derived directly from co-sited HD macroblocks, i.e. without having to compute the SD macroblock information from its corresponding SD image sequence.