Weighted open loop power control system
View Patent ↗A weighted open loop power control system for controlling transmission power levels using a spread spectrum time division duplex (TDD) technique having frames with timeslots for communication comprises a receiver and a transmitter. The receiver includes a reference channel data generator, a spreading and training sequence insertion device, an amplifier, a summer, a modulator, and an antenna. The transmitter includes a demodulator configured to receive a transmitted signal from the receiver, a channel estimation device, a data estimation device, and a weighted open loop power controller. The weighted open loop power controller includes a power measurement device, a pathloss estimation device configured to receive an interpreted power level from the data estimation device and estimate the pathloss and update a long term average of the pathloss, a quality measurement device, and a transmit power calculation device for determining the transmitter's power level and to control the receiver's amplifier.
1. A weighted open loop power control system for controlling transmission power levels using a spread spectrum time division duplex (TDD) technique having frames with timeslots for communication, the system comprising:
a receiver unit comprising:
a reference channel data generator configured to generate a reference channel data;
a spreading and training sequence insertion device configured to generate a communication burst by spreading the reference channel data and time-multiplex the reference channel data with a training sequence in appropriate timeslots;
an amplifier, in communication with the spreading and training sequence insertion device, the amplifier configured to amplify the communication burst;
a summer, configured to receive the amplified communication burst and sum the amplified communication burst with other communication bursts;
a modulator, configured to receive and modulate the summed amplified communication burst;
an antenna configured to transmit the modulated communication burst and information relating to the transmitted power level, over an air interface; and
a transmitter unit comprising:
a demodulator configured to receive the transmitted modulated communication burst and generate a baseband signal;
a channel estimation device configured to receive the baseband signal and extract channel information from the baseband signal;
a data estimation device configured to interpret the power level of the communication burst;
a weighted open loop power controller, said weighted open loop power controller comprising: a power measurement device for receiving the extracted channel information from the channel estimation device, a pathloss estimation device configured to receive the interpreted power level from the data estimation device and estimate the pathloss (L) and update a long term average of the pathloss (L 0 ) between the receiver unit and the transmitter unit, a quality measurement device to determine the quality of the estimated pathloss and weight the estimated pathloss by a weighting factor (α), and a transmit power calculation device, wherein the transmit power calculation device for determining the transmitter's unit power level and to control the receiver's unit amplifier.
2. The system of claim 1 , wherein the transmit power calculation device determines the transmitter's unit power level by adding a desired receiver power level to α(L−L 0 ) to L 0 to a constant value.