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 transmitting station (20) receives a transmit power command and a reference signal. The transmit power command (28) indicates an increase or decrease in transmission power for the transmitting station. A received power level of the reference signal is measured and the measured reference signal received power level is compared to a transmit power level of the reference signal to produce a pathloss estimate of the reference signal. A size of a change in transmit power level is determined using the pathloss estimate. A transmission power level of the transmitting station is adjusted in response to the transmit power command in an amount of the determined change in size. A communication is transmitted at the adjusted transmission power level.
Abstract:
A multiple access, spread-spectrum communication system processes a plurality of information signals received by a Radio Carrier Station (RCS) over telecommunication lines for simultaneous transmission over a radio frequency (RF) channel as a code-division-multiplexed (CDM) signal to a group of Subscriber Units (SUs). The RCS receives a call request signal that corresponds to a telecommunication line information signal, and a user identification signal that identifies a user to receive the call. The RCS includes a plurality of Code Division Multiple Access (CDMA) modems, one of which provides a global pilot code signal. The modems provide message code signals synchronized to the global pilot signal. Each modem combines an information signal with a message code signal to provide a CDM processed signal. The RCS includes a system channel controller coupled to receive a remote call. An RF transmitter is connected to all of the modems to combine the CDM processed signals with the global pilot code signal to generate a CDM signal. The RF transmitter also modulates a carrier signal with the CDM signal and transmits the modulated carrier signal through an RF communication channel to the SUs. Each SU includes a CDMA modem which is also synchronized to the global pilot signal. The CDMA modem despreads the CDM signal and provides a despread information signal to the user. The system includes a closed loop power control system for maintaining a minimum system transmit power level for the RCS and the SUs, and system capacity management for maintaining a maximum number of active SUs for improved system performance.
Abstract:
A method and apparatus is disclosed for minimizing multipath interference in wireless communication systems. A system comprises at least one transmitter and at least one receiver. In the transmitter, transmission beam parameters are dynamically modified using pseudo-random dithering or a sweeping function. The receiver receives an information signal regarding beam parameters or monitors the beam parameters and adjusts its receiving parameters accordingly to optimize its communication link. In an alternate embodiment, the receiver generates and sends feed back information to the transmitter wherein the feed back information may be used to modify beam parameters or perform other functions.
Abstract:
A method and apparatus for providing a wireless transmit/receive unit (WTRU) with access to at least one peripheral device, and/or at least one peripheral device associated with an available auxiliary device. The current peripheral device requirements of the WTRU are determined. The radio frequency (RF) environment of the WTRU is scanned to determine if there are any available wireless peripheral devices or wireless auxiliary devices proximate to the WTRU. A determination is also made as to whether there is a wired peripheral device or a wired auxiliary device available. A list of currently available peripheral devices is compiled by scanning at least one peripheral device registry associated with at least one of a wireless auxiliary device and a wired auxiliary device. The list is presented on the WTRU's display and a user selects at least one of the available peripheral devices from the list.
Abstract:
A multiple access, spread-spectrum communication system processes a plurality of information signals received by a Radio Carrier Station (RCS) over telecommunication lines for simultaneous transmission over a radio frequency (RF) channel as a code-division-multiplexed (CDM) signal to a group of Subscriber Units (SUs). The RCS receives a call request signal that corresponds to a telecommunication line information signal, and a user identification signal that identifies a user to receive the call. The RCS includes a plurality of Code Division Multiple Access (CDMA) modems, one of which provides a global pilot code signal. The modems provide message code signals synchronized to the global pilot signal. Each modem combines an information signal with a message code signal to provide a CDM processed signal. The RCS includes a system channel controller coupled to receive a remote call. An RF transmitter is connected to all of the modems to combine the CDM processed signals with the global pilot code signal to generate a CDM signal. The RF transmitter also modulates a carrier signal with the CDM signal and transmits the modulated carrier signal through an RF communication channel to the SUs. Each SU includes a CDMA modem which is also synchronized to the global pilot signal. The CDMA modem despreads the CDM signal and provides a despread information signal to the user. The system includes a closed loop power control system for maintaining a minimum system transmit power level for the RCS and the SUs, and system capacity management for maintaining a maximum number of active SUs for improved system performance.
Abstract:
PROBLEM TO BE SOLVED: To provide a code sequence generating apparatus for generating a plurality of spread code sequences having inter cross correlation within a prescribed range and having a prescribed inter code phase relation. SOLUTION: The spread code sequence generating apparatus includes a plurality of stages including a first stage and a final stage, wherein each stage has: a linear feedback shift register (LFSR) for demarcating a tap for generating a tap signal, applying a prescribed tap signal group to a logic circuit where the signals are composed and a feedback spread signal for input to the first stage is produced; a memory means being a first memory means for storing a plurality of spread code seeds, connected to the LFSR, and for respectively transferring each of a prescribed set of the spread code sequences of the spread code seed to be selected in response to a load signal; and a code generating unit control means for selecting one of a plurality of the spread code seeds and producing the load signal corresponding to the spread code. The LFSR transfers the tap signal from one stage to the next, transfers the feedback spread code value to the first stage, and demarcates a master spread code sequence by each of consecutive tap signal values of the final stage. COPYRIGHT: (C)2003,JPO
Abstract:
PROBLEM TO BE SOLVED: To provide an adaptive matching filter (AMF) apparatus for collecting signal power of a spread spectrum data channel from a spread spectrum signal. SOLUTION: The adaptive matching filter apparatus includes; a pilot vector correlation means for producing a plurality of multi-path signal weighting values depending on a plurality of multi-path signal carrier components; a local code sequence generating means for generating a plurality of local code sequences being code phase shift outputs of a prescribed spread code sequence; a plurality of spread code correlating units for producing respective multi-path data signal components having already been subjected to despread processing having carrier phase values in a data AMF for receiving the spread spectrum signal; a plurality of weighting means for producing a plurality of scaling and matched data signal components applying scaling to the multi-path data in response to the multi-path weighting values; and the data AMF means provided with a combining means for combining the scaling and matched data signal components to produce data values. COPYRIGHT: (C)2003,JPO
Abstract:
PROBLEM TO BE SOLVED: To provide a subscriber station unit for a large capacity multiple access spread spectrum communication system, which forms a plurality of concurrent user bearer channels through a prescribed radio frequency, to enable dynamic allocation of a bearer channel speed, while preventing multipath interference. SOLUTION: The subscriber station unit for the multiple access spread spectrum communication system includes a receiving means, a subscriber station unit controller, and a modem-processing means provided with a global pilot code acquiring means, a plurality of message code generators, a global pilot code tracking means, a phase-adjusting means and a plurality of message- acquiring means. COPYRIGHT: (C)2003,JPO
Abstract:
PROBLEM TO BE SOLVED: To reduce power consumption of each of a plurality of transceiver stations constituting a spread spectrum communication system, especially a mobile subscriber station unit, as much as possible.SOLUTION: In a spectrum communication system which maintains an initial transmission power level of a second transceiver station in an inactive state, a first transceiver station despreads reception signals by using a selected chip code associated with a specific spread spectrum signal from the second transceiver station and measures a power level of the despread specific signal. The second transceiver station sometimes transmits the specific spread spectrum signal during the inactive state to a first transceiver, and the first transceiver station receives it, measures a noise power level in a communication channel, estimates a system transmission power level, compares the measured values with the estimated values, and transmits automatic power control (APC) signals to the second transceiver station on the basis of a comparison result. The second transceiver station adjusts the initial transmission power level in response to the APC signals.