Abstract:
The present invention is related to a method and apparatus for implementing space frequency block coding (SFBC) in an orthogonal frequency division multiplexing (OFDM) wireless communication system. The present invention is applicable to both a closed loop mode and an open loop mode. In the closed loop mode, power loading and eigen-beamforming are performed based on channel state information (CSI). A channel coded data stream is multiplexed into two or more data streams. Power loading is performed based on the CSI on each of the multiplexed data streams. SFBC encoding is performed on the data streams for each of the paired subcarriers. Then, eigen-beamforming is performed based on the CSI to distribute eigenbeams to multiple transmit antennas. The power loading may be performed on two or more SFBC encoding blocks or on each eigenmodes. Additionally, the power loading may be performed across subcarriers or subcarrier groups for weak eigenmodes.
Abstract:
The present invention is related to a method and apparatus for implementing space frequency block coding (SFBC) in an orthogonal frequency division multiplexing (OFDM) wireless communication system. The present invention is applicable to both a closed loop mode and an open loop mode. In the closed loop mode, power loading and eigen-beamforming are performed based on channel state information (CSI). A channel coded data stream is multiplexed into two or more data streams. Power loading is performed based on the CSI on each of the multiplexed data streams. SFBC encoding is performed on the data streams for each of the paired subcarriers. Then, eigen-beamforming is performed based on the CSI to distribute eigenbeams to multiple transmit antennas. The power loading may be performed on two or more SFBC encoding blocks or on each eigenmodes. Additionally, the power loading may be performed across subcarriers or subcarrier groups for weak eigenmodes.
Abstract:
A method and system for utilizing smart antennas in transmission of messages between nodes are disclosed. A wireless communication system includes a plurality of nodes, and each node is capable of being connected to each other node. At least a portion of the nodes are provided with a smart antenna configured to generate a plurality of directional beams. Each node maintains a list of other nodes and beam configuration information to be used in transmission of messages to other nodes. When a source node is required to transmit to a target node, the source node retrieves the beam configuration information and transmits with a directional beam directed to the target node.
Abstract:
The present invention is related to a method and apparatus for implementing space frequency block coding (SFBC) in an orthogonal frequency division multiplexing (OFDM) wireless communication system. The present invention is applicable to both a closed loop mode and an open loop mode. In the closed loop mode, power loading and eigen-beamforming are performed based on channel state information (CSI). A channel coded data stream is multiplexed into two or more data streams. Power loading is performed based on the CSI on each of the multiplexed data streams. SFBC encoding is performed on the data streams for each of the paired subcarriers. Then, eigen-beamforming is performed based on the CSI to distribute eigenbeams to multiple transmit antennas. The power loading may be performed on two or more SFBC encoding blocks or on each eigenmodes. Additionally, the power loading may be performed across subcarriers or subcarrier groups for weak eigenmodes.
Abstract:
In orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) systems, a wireless transmit/receive unit (WTRU) selects a random access channel (RACH) and a phase for a constant amplitude zero auto correlation (CAZAC) sequence for RACH transmission. The WTRU then transmits a RACH transmission to a Node B via the selected RACH. Once the RACH transmission is detected, the Node B sends an acknowledgement (ACK) to the WTRU over an ACK channel. The Node B may transmit the ACK on a shared channel. The WTRU may ramp up transmit power while the RACH transmission is transmitted, or steps up transmit power of a subsequent RACH transmission. The RACH transmission and data transmission may be either time multiplexed or frequency multiplexed. A plurality of RACHs may be defined and one of the defined RACHs may be selected randomly or based on predetermined criteria.
Abstract:
A subscriber unit for use in a communication system includes a spread spectrum radio interface, responsive to a rate function signal from a base station, and first and second despreaders. The base station assigns the rate function spread-spectrum message channels and the first despreader recovers and modifies an information signal one of the spread spectrum message channels. The information channel mode is then modified for processing by the second despreader, with the second despreader supporting a different information signal rate. The subscriber unit has a capability of communicating with a dynamically changing a transmission rate of an information signal which includes multiple spread spectrum message channels. The system includes a closed loop power control system for maintaining a minimum system transmit power level for a radio carrier station and the subscriber units, and system capacity management for maintaining a maximum number of active subscriber units for improved system performance.
Abstract:
Methods and systems for receiving a primary and secondary synchronization signal from a cell are provided. The secondary synchronization signal may be derived from at least one of a set of sequences and received based on the timing of the received primary synchronization signal. Determining a time slot within a frame of the received secondary synchronization signal and a group of the cell is provided, wherein the time slot and the group are determined by at least one sequence of the secondary synchronization signal and at least one carrier out of a plurality of carriers used for one sequence out of the at least one sequence of the secondary synchronization signal. Determining a frame timing and a sequence used by the cell, based on the received primary synchronization signal and the secondary synchronization signal is further provided.
Abstract:
A multicellular communications system where transmission between a roving subscriber and multiple base station transceivers is maintained throughout the territory. Each mobile subscriber unit has global code seeds for the entire communications system or an updated neighbor list and continuously searches to access available cell base stations while maintaining a communication link with one base station. Candidate cell base stations are interrogated and communicated with. The candidate base station that requires less transmitting energy from the mobile subscriber unit is closely monitored. When the mobile subscriber unit can successfully communicate with less transmit power than currently required by the present base station, the mobile subscriber unit is handed off to the candidate base station transceiver.
Abstract:
The present invention is related to a method and apparatus for implementing space frequency block coding (SFBC) in an orthogonal frequency division multiplexing (OFDM) wireless communication system. The present invention is applicable to both a closed loop mode and an open loop mode. In the closed loop mode, power loading and eigen-beamforming are performed based on channel state information (CSI). A channel coded data stream is multiplexed into two or more data streams. Power loading is performed based on the CSI on each of the multiplexed data streams. SFBC encoding is performed on the data streams for each of the paired subcarriers. Then, eigen-beamforming is performed based on the CSI to distribute eigenbeams to multiple transmit antennas. The power loading may be performed on two or more SFBC encoding blocks or on each eigenmodes. Additionally, the power loading may be performed across subcarriers or subcarrier groups for weak eigenmodes.
Abstract:
A method and system for utilizing smart antennas in transmission of messages between nodes are disclosed. A wireless communication system includes a plurality of nodes, and each node is capable of being connected to each other node. At least a portion of the nodes are provided with a smart antenna configured to generate a plurality of directional beams. Each node maintains a list of other nodes and beam configuration information to be used in transmission of messages to other nodes. When a source node is required to transmit to a target node, the source node retrieves the beam configuration information and transmits with a directional beam directed to the target node.