摘要:
An iterative demodulator and decoder uses feedback attenuation to maintain proper balance between the demodulator and decoder. Balance is maintained by attenuating the influence of extrinsic information fed back from the decoder to the demodulator to prevent strong decisions by the decoder from overwhelming the demodulator.
摘要:
A base station is described herein that uses a root spreading code based code assignment to transmit signals to a mobile station. The mobile station can then suppress intra-block interference by effectively using a joint detection technique or a non-linear equalization technique to detect the transmitted symbols.
摘要:
Methods and apparatus for determining an impairment covariance matrix for use in an interference-suppressing CDMA receiver are disclosed. In several of the disclosed embodiments, precise information regarding signal propagation delays is not needed. An exemplary method includes the selection of a plurality of processing delays for processing a received CDMA signal. Net channel coefficients for the processing delays are estimated and used to calculate an impairment covariance matrix. The impairment covariance matrix is calculated as a function of the estimated net channel coefficients and the processing delays, without estimating a propagation medium channel response for the received signal.
摘要:
A system and method for adapting a broadcast service in a cellular communication network. A base station receives indications of channel quality from registered users of the broadcast service, and adapts broadcast transmission parameters to improve channel quality for the broadcast users if at least one of the broadcast users indicates that channel quality needs to be improved. If none of the broadcast users indicates that channel quality needs to be improved, the base station adapts the transmission parameters to decrease channel quality for the broadcast users. The transmission parameters may be adapted by techniques such as changing the broadcast transmit power, changing the level of FEC encoding and modulation, changing the number of channel resources allocated, or changing the transmission data rate for the broadcast service. When multiple base stations transmit the broadcast information, a base station controller may minimize network resource utilization by coordinating adaptation control among the base stations.
摘要:
Where two or more multi-valued digital data symbols are modulated so that they overlap after passing through a channel, forming a combined signal, a receiver receives the combined signal and forms detection statistics to attempt to recover the symbols. Where forming detection statistics does not completely separate the symbols, each statistic comprises a different mix of the symbols. A receiver determines the symbols which, when mixed in the same way, reproduce or explain the statistics most closely. For example, the receiver hypothesizes all but one of the symbols and subtracts the effect of the hypothesized symbols from the mixed statistics. The remainders are combined and quantized to the nearest value of the remaining symbol. For each hypothesis, the remaining symbol is determined. A metric is then computed for each symbol hypothesis including the so-determined remaining symbol, and the symbol set producing the best metric is chosen as the decoded symbols.
摘要:
A method and apparatus for controlling the transmit power of a mobile device in a mobile communication network takes the level of self-interference into account to perform inner-loop power control. For normal inner-loop power control, a signal quality estimate is compared to a signal quality target and power control commands are generated based on the comparison. When self-interference is the dominant impairment in the received signal, a “fast break” is introduced to change inner-loop power control command generation.
摘要:
A method and apparatus in a radio receiver for canceling interference from a high power, high data rate signal received in a combined signal that includes a contribution from the high power signal and a contribution from a lower power signal. It is first determined whether the high power signal was correctly received. A CRC checksum may be used to determine whether the high power signal was received with a good reliability. Thereafter, the contribution of the high power signal is removed from the received signal only if the high power signal was correctly received. The contribution of the high power signal may be removed by hard-subtracting the contribution of the high power signal from the received signal if all of the bits of the checksum are correct, and soft-subtracting the contribution of the high power signal from the received signal if most, but not all, of the bits in the checksum are correct.
摘要:
According to one embodiment taught herein, a method of determining impairment correlations between a plurality of delays of interest for a received CDMA signal comprises generating kernel functions as samples of a net channel response of the received CDMA signal taken at defined chip sampling phases for delay differences between the plurality of delays of interest. In a parametric Generalized Rake (G-Rake) receiver embodiment, the delays of interest represent the delay positions of the fingers being used to characterized received signal. In a chip equalizer receiver embodiment, the delays of interest represent the delay positions of the equalizer taps. The method continues with determining impairment correlations based on convolving the kernel functions. Corresponding receiver circuits, including an impairment correlation estimation circuit configured for parametric G-Rake operation, may be implemented in a variety of communication devices and systems, such as in wireless communication network base stations and mobile stations.
摘要:
Methods and systems for selecting a frequency hopping mode for a communication in a communication system having a plurality of transmission schemes are provided. One of the plurality of transmission schemes to be used for the communication is determined. One of a plurality of candidate frequency hopping modes is selected as the frequency hopping mode for the communication based on the determined transmission scheme for the communication. Methods and systems for transmitting a communication packet in a communication system having a plurality of transmission schemes are also provided.
摘要:
An improved system and method for rate detection of transmitted signals is disclosed for use in a IS-95 CDMA downlink. For each speech frame, one of four possible bit rates is used to encode the frame according to the standard. The present invention describes a receiver and various processes that are able to detect which rate was sent without the aid of flag bits or other mode indication information. According to various embodiments of the invention different rate detection processes which can exploit additional code information, such as CRC checks and convolutional coding, are disclosed.