Abstract: Cooperative communication is a technique that can be employed to meet the increased throughput needs of next generation WiMAX systems. In a cooperative scenario, multiple stations can jointly emulate the antenna elements of a multi-input multi-output system in a distributed fashion. A framework for a randomized distributed space-time coding (“R-DSTC”) technique in the emerging relay-assisted WiMAX network, and the development of a cooperative medium access control (“MAC”) layer protocol, called CoopMAX, for R-DSTC deployment in an IEEE 802.16 system, is described. The technique described couples the MAC layer with the physical (PHY) layer for performance optimization. The PHY layer yields significant diversity gain, while the MAC layer achieves a substantial end-to-end throughput gain.

Abstract: Various embodiments of the invention may use adaptive polling in a wireless network when one or more consecutive polls show that the polled station has no data to transmit. When triggered to perform adaptive polling, a base station may wait for increasingly long intervals between polls to a particular subscriber station, until some maximum interval has been reached. In some embodiments, the intervals may increase exponentially.

Abstract: A distributed and opportunistic medium access control (MAC) layer protocol for randomized distributed space-time coding (R-DSTC), which may be deployed in an IEEE 802.11 wireless local area network (WLAN), is described. Unlike other cooperative MAC designs, there is no need to predetermine, before packet transmission, which stations will serve as relays. Instead, the MAC layer protocol opportunistically recruits relay stations on the fly. Network capacity and delay performance is much better than legacy IEEE 802.11g network, and even cooperative forwarding using one relay station. Avoiding the need to collect the station-to-station channel statistics considerably reduces overhead otherwise required for channel measurement and signaling.

Abstract: Cooperative communication is a technique that can be employed to meet the increased throughput needs of next generation WiMAX systems. In a cooperative scenario, multiple stations can jointly emulate the antenna elements of a multi-input multi-output system in a distributed fashion. A framework for a randomized distributed space-time coding (“R-DSTC”) technique in the emerging relay-assisted WiMAX network, and the development of a cooperative medium access control (“MAC”) layer protocol, called CoopMAX, for R-DSTC deployment in an IEEE 802.16 system, is described. The technique described couples the MAC layer with the physical (PHY) layer for performance optimization. The PHY layer yields significant diversity gain, while the MAC layer achieves a substantial end-to-end throughput gain.

Abstract: A distributed and opportunistic medium access control (MAC) layer protocol for randomized distributed space-time coding (R-DSTC), which may be deployed in an IEEE 802.11 wireless local area network (WLAN), is described. Unlike other cooperative MAC designs, there is no need to predetermine, before packet transmission, which stations will serve as relays. Instead, the MAC layer protocol opportunistically recruits relay stations on the fly. Network capacity and delay performance is much better than legacy IEEE 802.11g network, and even cooperative forwarding using one relay station. Avoiding the need to collect the station-to-station channel statistics considerably reduces overhead otherwise required for channel measurement and signaling.

Abstract: A method selects antennas in an OFDMA network. A channel state of a downlink is measured using a downlink subframe received in a mobile station from a base station. A channel state of an uplink is measured using an uplink subframe received in the base station from the mobile station. Next, the method compares the channel states to determine whether the downlink and the uplink are reciprocal or not. The mobile station can perform receive antenna selection based on the quality of the downlink channel state. The mobile station can also perform transmit antenna selection when instructed by the base station.

Abstract: A method selects antennas in an OFDMA network. A channel state of a downlink is measured using a downlink subframe received in a mobile station from a base station. A channel state of an uplink is measured using an uplink subframe received in the base station from the mobile station. Next, the method compares the channel states to determine whether the downlink and the uplink are reciprocal or not. The mobile station can perform receive antenna selection based on the quality of the downlink channel state. The mobile station can also perform transmit antenna selection when instructed by the base station.

Abstract: Various embodiments of the invention may use adaptive polling in a wireless network when one or more consecutive polls show that the polled station has no data to transmit. When triggered to perform adaptive polling, a base station may wait for increasingly long intervals between polls to a particular subscriber station, until some maximum interval has been reached. In some embodiments, the intervals may increase exponentially.

Abstract: Generally triangular first and second longitudinal side portions are arranged in the lower half region of a longitudinal side member between the first and second flat members vertically spaced apart from each other and form projections and depressions longitudinally and alternately. Generally inverted triangular third and fourth longitudinal side portions are arranged in the upper half region between the first and second flat members and form projections and depressions longitudinally and alternately. The first longitudinal side portions are vertically opposed to the third longitudinal side portions such that the first and third longitudinal side portions form projections and depressions. The second longitudinal side portions are vertically opposed to the fourth longitudinal side portions such that the second and fourth longitudinal side portions form projections and depressions.