Abstract: A method and apparatus for mixing Basic Service Set (BSS) and mesh traffic is presented. A same channel or a same radio is shared for mesh traffic and BSS traffic. The sharing of the channel including reserving a channel for BSS traffic by a Mesh Access Point (MAP), the reserving comprising sending a CC-RTS or a CC-CTS addressed to the MAP and/or blocking use of the channel by a BSS stations when the channel is not reserved for BSS traffic, the blocking use of the channel comprising the MAP sending a frame setting a NAV in the BSS. The shared radio is switchable between serving the BSS traffic and serving the mesh traffic.

Abstract: A method and apparatus are disclosed that enable taking into consideration the variation in channel occupancy of a particular terminal or terminals during the call admission process. A channel utilization manager accounts for the probabilistic nature of the call admission decision by using a pre-determined, statistically justified value to represent the channel occupancy. The “per-call” channel occupancy value is determined by a number of factors, including the shared-communications channel data rate. Channel occupancy is incorporated into one or more cumulative distribution functions (CDF), which are evaluated by the channel utilization manager as part of the call admission process. In turn, each channel-occupancy CDF of a shared-communications channel can be generated from a CDF of the terminals' data rates on that channel, which data rates can be determined analytically or empirically.

Abstract: A method and apparatus for limiting the length of a service period in a Wireless Local Area Network (WLAN) including an Access Point (AP) and at least one station is presented. A maximum service period (SP) length for at least one station is determined. A value in a max SP length field in a control field of an uplink frame sent from said station to said AP is set. The value of the max SP length field is determined at the AP. Frame transmittal from the AP to the station is triggered during a service period when the value is non-zero, while downlink frame delivery from the AP to the station is prevented when the value is zero.

Abstract: Using low PF values in conjunction with traffic-adapted contention windows leads to substantial decreases in delay and jitter. In general, adaptation to traffic reduces contention or delay: opening up the contention window in congestion and closing it on relief. Residual backoff adaptation provides for the reduction of the already decremented backoff values of stations that interrupted the backoff countdown process due to a transmission. It is good to adapt both the contention window and the residual backoff in order to avoid jitter. Otherwise, if the contention window is reduced but residual backoffs stay unchanged, new arrivals will enjoy shorter backoff delays than older ones, resulting in greater jitter. Adjusting both preserves the relative ordering of backoff counter values, which implies also some form of age ordering. Different adjustments can be applied to different priority traffic.

Abstract: A method, apparatus and computer program product for preventing occurrences of the hidden node problem are presented. A transmission request (CC-RTS) is received from a source node, the CC-RTS frame including a reservation duration value indicating the length of time needed for a transmission reservation. A timer is adjusted for the period other nodes must refrain from transmitting on the channel (NAV) equal to a duration of a transmission request/transmission response (CC-RTS/CC-CTS) handshake. When the CC-RTS has been denied, then a second CC-RTS frame is received having a reservation duration value of zero, and when the CC-RTS is accepted then the NAV is extended to remainder of the reservation duration value of the original CC-RTS frame. The CC-RTS and CC-CTS are sent at a more robust PHY mode than traffic frames.

Abstract: A method, apparatus and computer program product for coordinating adjacent channel transmissions on multiple-radio nodes is presented. A Maximum Channel Occupancy Duration (MCOD) limit for a length of an overall transmit period is defined. A set of timers (NNAV) for each neighbor node is maintained, each of said NNAV including a first timer (CTSNNAV) for the channel which, if set, indicates the maximum duration of a transmission to said neighbor node and a second timer (RTSNNAV) for a channel which, if set, prevents the neighbor node from authorizing a transmission the channel.

Abstract: A method, apparatus and computer program product for the express forwarding frames having multiple fragments are presented. A timer (NAV) is maintained at each respective node of a wireless Local Area Network (LAN). At least two fragments of a frame are designated as a Time Sensitive Quality of Service (TSQ) frame fragments to be express forwarded. A duration field of each of the TSQ frame fragments is incremented by a first predetermined time increment (DT0) before the TSQ frame fragments are forwarded. The TSQ frame fragments are transmitted when a last frame fragment is ready to be transmitted. A response is received from the second node wherein non-forwarding neighboring nodes each set their NAV according to a value equal to the duration field of the response. The second node attempts forwarding of the TSQ frame fragments when acknowledgement of receipt of the TSQ frame fragments is complete.

Abstract: A method, apparatus and computer program product for avoiding exposed nodes in Wireless local Area Networks is presented. The method includes maintaining at a node a first timer (NAV_RTS) for a channel which, if set, prevents the node from authorizing a transmission on the channel to itself and maintaining at the node a second timer (NAV_CTS) for the channel which, if set, prevents the node from transmitting on the channel. The method further includes updating the NAV_RTS when a transmission request (CC-RTS) frame is received having a reservation duration value greater than zero and greater than a current value of the NAV_RTS, and updating the NAV_CTS when a transmission response (CC-CTS) frame is received having a reservation duration value greater than zero and greater than a current value of the NAV_CTS.

Abstract: A novel distributed architecture for deploying a plurality of wireless local-area networks is disclosed. The illustrative embodiment enables some of the protocols of a protocol stack to be “off-loaded” from wireless access points to a remote central controller. In particular, protocols whose services operate correctly regardless of the presence or magnitude of processing and communication delays are off-loaded to the central controller, while protocols whose services operate correctly only when delays are below a threshold remain in the wireless access points. The illustrative embodiment thus enables the use of “thin” (i.e., reduced-functionality) access points, thereby reducing cost and facilitating maintenance when deploying multiple wireless local-area networks (for example, on a corporate or academic campus).

Abstract: A method of providing power management in a Wireless Local Area Network (WLAN) is presented. The method includes receiving a Traffic Indication Map (TIM) at a station, indicating the presence of buffered frames, associated with any AC, for the station at an Access Point (AP). The method further includes sending, by the station, one of an uplink data frame if one is buffered, and a null frame to retrieve the buffered frames from said AP. The station remains awake to receive frames from the AP until a downlink frame is received containing an indication that it is the last frame to be transmitted in the service period. The method may further include determining at the end of service period whether there are more frames remaining buffered for the station at the AP.

Abstract: A method of providing power management in a Wireless Local Area Network (WLAN) is presented. The method includes receiving a Traffic Indication Map (TIM) at a station, indicating the presence of buffered frames, associated with any AC, for the station at an Access Point (AP). The method further includes sending, by the station, one of an uplink data frame if one is buffered, and a null frame to retrieve the buffered frames from said AP. The station remains awake to receive frames from the AP until a downlink frame is received containing an indication that it is the last frame to be transmitted in the service period. The method may further include determining at the end of service period whether there are more frames remaining buffered for the station at the AP.

Abstract: A method, apparatus and computer program product for coordinating adjacent channel transmissions on multiple-radio nodes is presented. A Maximum Channel Occupancy Duration (MCOD) limit for a length of an overall transmit period is defined. A set of timers (NNAV) for each neighbor node is maintained, each of said NNAV including a first timer (CTSNNAV) for the channel which, if set, indicates the maximum duration of a transmission to said neighbor node and a second timer (RTSNNAV) for a channel which, if set, prevents the neighbor node from authorizing a transmission the channel.

Abstract: A method and apparatus providing delivery of buffered frames in a Wireless Local Area Network (WLAN) is presented. The method and apparatus determines an occurrence of at least one non-APSD station in said WLAN, and when at least one non-Automatic Power Save Delivery (APSD) station is found, then maintains a legacy power saving buffer for each non-APSD station. The method and apparatus also determines an occurrence of at least one APSD station in the WLAN, and when at least one APSD station is found, then maintains at least one APSD buffer for each APSD enabled station. During a service period, frames are transmitted from the at least one APSD buffer.

Abstract: An apparatus and method for polling stations that transmit periodic traffic streams are disclosed. The illustrative embodiment polls the station in accordance with a polling schedule that is generated to reduce the delay between (i) when the station queues a frame, and (ii) when the station transmits the frame. This reduces the waiting time of the frame in the station, and is, therefore, especially advantageous for latency-sensitive applications such as voice and video telecommunications. In accordance with the illustrative embodiment, a station that expects to periodically queue a frame for transmission sends a polling request to the polling coordinator, which request enables the polling coordinator to generate an advantageous polling schedule.

Abstract: An apparatus and methods for handling emergency message frames (e.g., “911” call frames, etc.) sent by a station in a wireless local-area network are disclosed. The illustrative embodiment increases the probability with which an emergency message frame is accorded the highest quality-of-service by modifying one or more IEEE 802.11e parameters (e.g., back-off contention window length, Arbitration Inter-Frame Space [AIFS], etc.) for a station or access point that transmits an emergency message frame.

Abstract: A method and system reduce interference between overlapping first and second wireless LAN cells in a medium. Each cell includes a respective plurality of member stations and there is at least one overlapped station occupying both cells. An inter-cell contention-free period value is assigned to a first access point station in the first cell, associated with an accessing order in the medium for member stations in the first and second cells. The access point transmits a beacon packet containing the inter-cell contention-free period value, which is intercepted at the overlapped station. The overlapped station forwards the inter-cell contention-free period value to member stations in the second cell. A second access point in the second cell can then delay transmissions by member stations in the second cell until after the inter-cell contention-free period expires.

Abstract: A method, apparatus and computer program product for the express forwarding bypass are presented. A timer (NAV) is maintained at each respective node of a wireless LAN, the timer (NAV) set to a corresponding time period during which the respective node must refrain from transmitting on a channel. The first node of said plurality of nodes has a time-critical (TC) frame. The first node detects a frame to be express-forwarded by a second node. The first node decrements the duration field by a first predetermined time increment (DT0) before setting its NAV. The first node attempts transmission of the TC frame or back off countdown when the NAV of said first node expires.

Abstract: A method and apparatus for conveying priority of buffered frames to power saving stations in a Wireless Local Area Network (WLAN) including an Access Point (AP) and at least one power saving station is presented. The method and apparatus indicate to a station the presence of at least one buffered frame in at least one of legacy buffers and Automatic Power Save Delivery (APSD) buffers in the AP for the station. The AP receives an indication from the station that the station is ready to receive at least one of the buffered frames for the station. The AP then selects a buffer for releasing at least one buffered frame to the station, determines a number of frames to transmit from the selected buffer, and transmits the number of frames from said buffer to the station.

Abstract: A method and system reduce interference between overlapping first and second wireless LAN cells in a medium. Each cell includes a respective plurality of member stations and there is at least one overlapped station occupying both cells. An inter-cell contention-free period value is assigned to a first access point station in the first cell, associated with an accessing order in the medium for member stations in the first and second cells. The access point transmits a beacon packet containing the inter-cell contention-free period value, which is intercepted at the overlapped station. The overlapped station forwards the inter-cell contention-free period value to member stations in the second cell. A second access point in the second cell can then delay transmissions by member stations in the second cell until after the inter-cell contention-free period expires.

Abstract: Spectrum monitoring measurements are made by microcell base stations in a layered cellular network, while not serving calls or engaged in processing calls. The microcell base station transmits a first control message from to a microcell mobile station, to increase the duration for the mobile station to reside in the camping state on a control channel of the microcell base station. The microcell base station transmits a second control message from the microcell base station to the microcell mobile station, to increase the duration for the mobile station to reside in a call origination state while attempting to access a control channel of the microcell base station. Then, to perform the spectrum monitoring measurement, the base station's transmitter is turned off, the receiver is retuned to the frequency to be monitored, a signal strength measurement taken on that frequency, the receiver is retuned back to its assigned frequency, and the transmitter is turned back on, all in a short time interval.