Abstract:
A wireless spread spectrum communication system comprises a base station and at least one subscriber unit. The base station has a plurality of modems producing at least one channel signal and a global signal. A signal combiner combines the at least one channel and global signals. A radio frequency transmitter transmits the combined signal. A global power control processor determines a desired transmit power level of the combined signal. A power controller adjusts a transmit power level of the global signal to the desired transmit power level. The at least one subscriber unit receives a channel signal of the at least one channel and global signal.
Abstract:
A receiver employing CDMA techniques estimates background noise based on a periodically updated code. The transmitted signal includes a periodically updated code of a predetermined type and wherein the received signal has CW interference in addition to the transmitted signal. The decision circuit determines if a value representing the likelihood of detection of the code exceeds a predetermined threshold. In the case of a pilot signal not being detected within a predetermined time period which corresponds to code update period, the background noise estimator obtains a new background estimation.
Abstract:
A spread spectrum time division duplex user equipment uses frames with time slots for communication. It receives power commands and receives a first communication having a transmission power level in a first time slot. It measures a power level of the first communication as received and determines a pathloss estimate based on in part the measured received first communication power level and the first communication transmission power level. The user equipment sets a transmission power level for a second communication in a second time slot from the user equipment based on in part the pathloss estimate weighted by a quality factor and adjusted by the power commands.
Abstract:
A method for using a wireless digital base station to receive, process and transmit a plurality of communications having independent data rates establishing a first communication channel having a first data communication rate to support a first communication; determining the data rate required to support the first communication; selecting one or more transmission channels, from a plurality of available transmission channels, required to support said required data rate; and transmitting the first communication using one or more selected transmission channels. The plurality of available transmission channels includes at least one B or D channel.
Abstract:
The present invention is a user equipment (UE), including a receiver and method for receiving one of a plurality of channels in a communication signal. An adaptive matched filter produces a filtered signal by using a weighting signal. A rake receiver produces a filter weighting signal using a pseudo-noise signal generator. A channel despreader despreads the filtered signal using the pseudo-noise signal generated to produce a despread channel signal of the selected channel. A pilot channel despreader despreads the filtered signal using a pseudo-noise signal generator to produce a despread pilot signal of the pilot channel. A hard decision processor receives the despread channel signal of the selected channel and produces a correction signal. A phase-locked loop utilizes at least the despread pilot signal and produces a phase correction signal which is applied to produce phase-corrected channel signals.
Abstract:
A method of controlling transmission power during the establishment of a channel in a CDMA communication system utilizes the transmission of a short code from a subscriber unit to a base station during initial power ramp-up. The short code is a sequence for detection by the base station which has a much shorter period than a conventional spreading code. The ramp-up starts from a power level that is lower than the required power level for detection by the base station. The subscriber unit quickly increases transmission power while repeatedly transmitting the short code until the signal is detected by the base station. Once the base station detects the short code, it sends an indication to the subscriber unit to cease increasing transmission power. The use of short codes limits power overshoot and interference to other subscriber units and permits the base station to quickly synchronize to the spreading code used by the subscriber unit.
Abstract:
A base station for receiving a transmitted signal in a communication system employing CDMA techniques wherein the transmitted signal includes a plurality of short codes, each of which is transmitted repetitively over a fixed period of time and where the received signal has CW interference in addition to the transmitted signal. The base station detects the presence of the short code in a plurality of time phases of the received signal by calculating a likelihood ratio for each phase. The likelihood ratio takes into account the current short code.
Abstract:
A method for generating complex four-phase pseudo-random code sequences which may be directly mapped to a quadrature phase shift keying (QPSK) signal constellation.
Abstract:
A method for using a wireless digital subscriber unit to receive, process and transmit a plurality of communications having independent data rates includes establishing a first communication channel having a first data communication rate to support a first communication; determining the data rate required to support the first communication; selecting one or more transmission channels, from a plurality of available transmission channels, required to support the required data rate; and transmitting the first communication using one or more selected transmission channels. The plurality of available transmission channels includes at least one B or D channel.
Abstract:
A method for using a wireless digital base station to receive, process and transmit a plurality of communications having independent data rates establishing a first communication channel having a first data communication rate to support a first communication; determining the data rate required to support the first communication; selecting one or more transmission channels, from a plurality of available transmission channels, required to support said required data rate; and transmitting the first communication using one or more selected transmission channels. The plurality of available transmission channels includes at least one B or D channel.