Abstract: An adaptive sliding block Viterbi decoder (ASBVD) includes forward and backward Viterbi processors, a state estimator and a control unit. The processors generate metrics of states and of transitions between the states associated with an encoder, based on encoded input information symbols received via a communications channel. Each processor includes a plurality of buffers for storing information symbols so that a number of the encoded input information symbols can be concurrently decoded. The state estimator estimates a current state of a code trellis based on the generated metrics, and the processors decode the stored information symbols based on the estimated current state. The control unit adapts the number of encoded input information symbols to be concurrently decoded based on a condition of the communications channel, and selectively controls the number of buffers that are enabled in accordance with the number of encoded input information symbols to be concurrently decoded.

Abstract: A dynamic voltage scaling system for a packet-based data communication transceiver includes a constant voltage supply, a variable voltage supply, and a voltage control unit. The constant voltage supply is configured to supply a constant voltage to at least one parameter-independent function of the transceiver, and the variable voltage supply is configured to supply a variable voltage in accordance with a control signal to at least one parameter-dependent function of the transceiver. Parameter-independent transceiver functions perform operations independent of a predetermined parameter and parameter-dependent transceiver functions perform operations dependent on the predetermined parameter The voltage control unit is configured to generate the control signal based on information provided by at least one parameter-independent transceiver function about the predetermined parameter.

Abstract: A method generates signals in a transmitter of a multiple-input, multiple-output wireless communications system. The transmitter includes Nt transmit antennas. A transmit covariance matrix Rt determined using statistical state information of a channel. The transmit covariance Rt matrix is decomposed using transmit eigenvalues ?t to obtain a transmit eigenspace Ut according to Rt=Ut?tU†t, where † is a Hermitian transpose. A pilot eigenspace Up is set equal to the transmit eigenspace Ut. A NtxTp block of pilot symbols Xp is generated from the pilot eigenspace Up and pilot eigenvalue ?p according to Xp=Up?p1/2. A data eigenspace Ud is set equal to the transmit eigenspace Ut. In addition, a Nt×Nt data covariance matrix Qd is generated according to Ud?dU†d, where ?d are data eigenvalues. A NtxTd block of data symbols is generated, such that an average covariance of each of the columns in the block of data symbols Xd equals the data covariance matrix Qd.

Abstract: A method and system access a channel in a wireless network of nodes. A coordinator transmits periodically a beacon, in which time between two consecutive beacons constitute a beacon interval. The coordinator and other nodes transceive a superframe during the beacon interval, in which the superframe begins with an active interval, which is immediately followed by an inactive interval, and in which the active interval begins with a contention free period, which is immediately followed by a contention access period, which is immediately followed by the inactive interval.

Abstract: A computer implemented method selects antennas in a multiple-input, multiple-output wireless local area network that includes multiple stations, and each station includes a set of antennas. Multiple consecutively transmitted sounding packets are received in a station. Each sounding packet corresponds to a different subset of the set of antennas. A channel matrix is estimated from the multiple consecutively transmitted sounding packets, and a subset of antennas is selected according to the channel matrix.

Abstract: The invention provides a data structure embodied in a computer readable media. The data structure is a protocol data packet (PDU) communicated in a mobile multihop network between stations. The data structure includes a relay media access header, a payload and an optional cyclical redundancy checksum for the protocol data unit; and an indication whether the PDU is a relay media access protocol data unit or not.

Abstract: An ad-hoc wireless communication network includes multiple nodes. Each node maintains a routing table. The routing table is constructed by broadcasting route request packets from a source node. The request packet includes an address of a destination node. Intermediate nodes in the network receiving the request packet, determine power and delay cost associated with the intermediate node participating in the route. If the cost is less than a threshold value, then the intermediate node participates in the routing of packets for other nodes. The intermediate node then sends a reply packet back to the source node. The reply packet includes the intermediate node addresses, as well as the power and delay costs. The source can thus construct the routing table. The source node can select a particular node for transferring application data packets based on either the power cost, the delay cost or both costs.

Abstract: A system and method schedule series of packets for transmission between terminals in a single wireless channel of a packet-switched local area network. The local area network can operate in an ad hoc mode or in infrastructure mode. A transmission rate is assigned to each of the terminals. The terminals can be mobile. Different terminals can be assigned different transmission rates, depending on a quality of the channel. That is, terminals transmitting via an error-free channel are assigned a higher transmission rate than terminals transmitting via an error-prone channel. Then, the series of packets are scheduled for transmission between the terminals such that each terminal receives a substantially equal amount of transmission time over an extended period of time.

Abstract: A method determines a position of a target object. A window function is applied repeatedly to a first signal and a second signal of a pair of radio signals received at a pair of passive sensors from a target object while time shifting the window function during a correlation interval to produce a first windowed signal and a second windowed signal for each application. The first windowed signals are cross-correlating with the second windowed signals to determine a peak for each cross-correlation. The peaks are compared sequentially in time with a predetermined threshold to detect a first pulse in the first signal and a first pulse in the second signal. A delay between the first pulses indicative of a position of the target object.

Abstract: A method accesses channels in an OFDMA mobile multihop relay wireless network. The method partitions a downlink sub-frame into at least one downlink access zone and a set of downlink relay zones. The uplink subframe is partitioned into at least one uplink access zone and a set of uplink relay zones. During the downlink access zone, the base station and the relay stations transmit only to the set of mobile stations. During the downlink relay station, the base station and the set of relay stations communicate with each other, while the mobile stations are idle. During the uplink access zone, the set of mobile stations transmit only to the set of relay stations and the base station. During the uplink relay station, the base station and the set of relay stations communicate with each other, while the mobile stations are idle.

Abstract: A method and system switches antennas in an orthogonal frequency division multiplexed access (OFDMA) wireless communication system while transmitting symbols. Each symbol includes a cyclic prefix and a block of data signals. The symbols are transmitted during a first portion of a transmission time interval (TTI), from a first antenna. Then, the RF chain is switched to a second antenna to transmit the symbols, and in which the switching is performed substantially between transmitting two consecutive transmitted symbols.

Abstract: A method detects unused frequency bands in a cognitive radio network. Multiple frequency bands for RF signals are sensed using an antenna array including a plurality of elements coupled to a receive RF chain, in which the plurality of elements are individually controllable. For each frequency band, multiple spatial directions are sensed for the RF signals using the antenna array. A particular frequency band and a particular direction and a particular time slot are assigned as an available frequency band, an available direction and a particular time slot for transmitting RF signals in a cognitive radio if the RF signals are not sensed in the particular spatial direction for the particular frequency band, and in which the RF signals are transmitted by a transmit chain connected to the antenna array.

Abstract: Handover procedures and a collection of new handover MAC management messages are provided for a wireless mobile multi-bop relay (MMR) network. The types of handovers supported include macro diversity handover (MDHO) and fast access station switching (FASS). The handover procedures for these two types of handover and the MAC messages are described for nine main classes of network topologies. The nine classes of topology are further classified into to main categories, namely, intra multi-hop base station (MR-BS), when and where the handover is in the MMR cell, and inter MR-BS handover, when and where the handover is between two different MMR cells.

Abstract: A method communicates packets in a relay network. The packets are communicated from a set of mobile stations to a relay station using a set of connections, there being one connection between each mobile station and the relay station. The packets are communicated between the relay station and a base station using a relay tunnel connection, between the relay station and its adjacent relay station the packets are communicated using the relay tunnel connection.

Abstract: A method and system enables and improves performance of hybrid automatic repeat request (HARQ) operations on channels between stations of an orthogonal frequency division multiple access (OFDMA) wireless communication network. There, the number of parallel HARQ channels is increased adaptively, and one connection identifier is used to unambiguously identify a set of MAC protocol data units (MPDUs) communicated over parallel HARQ channels. A sequence number is used to avoid out-of-order MPDU delivery when MPDUs are transmitted over parallel HARQ channels. The MPDUs can be concatenated or encapsulated. The maximum number of the parallel HARQ channels can be increased to 256, and can be negotiated when a station enters or re-enters the network.

Abstract: In a cellular network, symbols are encoded and modulated to produce a modulated signal The modulated signal is mapped to a subcarrier using a spatial mapping matrix. An inverse fast Fourier transform is applied to the mapped signal to produce groups of tones. The groups of tones are transmitting concurrently to multiple receivers using the same channel as orthogonal frequency-division multiplexing access (OFDMA) signals. There is one group of tones for each receiver.

Abstract: A method transmits packets over a single channel in a wireless communication network that includes multiple nodes. Access to the channel is gained in a transmitting node. Then, a block of packets is transmitted to a receiving node via the channel. The transmitting node receives only a single acknowledgement packet from the receiving node in response to transmitting the block of packets.

Abstract: A method selectively acknowledges data packets in a network including a multiple stations connected by a common wireless channel. A transmitting station requests a block acknowledgement from a receiving station. The transmitting station transmits a block of data packets to the receiving station. The receiving station determines a number of successfully received data packets and a number of incorrectly received packets. Then, the receiving station selectively acknowledges only the successfully received data packets if the number of usefully received data packets is less than the number of incorrectly received data packets, and otherwise acknowledging only the incorrectly received packets.

Abstract: A method for antenna subset selection by joint processing in RF and baseband in a multi-antenna systems. Lt input data streams are generated in a transmitter for either diversity transmission or multiplexing transmission. These streams are modulated to RF signals. These signals are switched to the t branches associated with the t transmit antennas, and a phase-shift transformation is applied to the RF signals by a t×t matrix multiplication operator ?1, whose output are t?Lt RF signals. These signals are transmitted over a channel by t antennas. The transmitted signals are received by r antennas in a receiver. A phase-shift transformation is applied to the r RF signals by a r×r matrix multiplication operator ?2. Lr branches of these phase shifted streams are demodulated and further processed in baseband to recover the input data streams.

Abstract: A method communicates packets in a relay network. Multiple packets are communicated between a set of mobile stations and a relay station using a set of connections. There is one connection between each mobile station and the relay station. The multiple packets are aggregated on single connection between the relay station and a base station.