Abstract:
A despreading section (104) outputs a signal representing the number of paths for which despreading is conducted to a likelihood calculating section (108). An fD determining section (107) determines the Doppler frequency (fD) of the fading fluctuation of the propagation path between each communication terminal and the base station device from the despread signal. The likelihood calculating section (108) calculates the likelihood of the reported value transmitted from each communication terminal on the basis of the number of paths for which despreading is carried out and the Doppler frequency. A transmission destination determining section (151) determines a communication terminal to which a downlink high-speed packet is transmitted on the basis of the judgment value which is the product of the reported value by the likelihood. A modulation method determining section (152) determines the coding rate and modulation method of the downlink high-speed packet on the basis of the judgment value. By transmitting a downlink high-speed packet in consideration of the error included in the reported value, the number of retransmissions is reduced, the transmission efficiency is improved, and the system capacity is increased.
Abstract:
Techniques for recovering data transmitted on a physical channel in which channelization code is not known at the time of the data recovery. A modulated signal is received and processed to provide received samples (612). A hypothesized channelization code (e.g., an OVSF code in the W-CDMA system) is selected (616) and used to process the received samples to generate partially processed symbols (618). The hypothesized channelization code is a "base" code that can be used to generate all possible channelization codes that may have been used for the physical channel. Intermediate results representative of the partially processed symbols are stored (622) and, upon determination of the actual channelization code (624), further processed (626) in accordance with the actual and hypothesized channelization codes to provide the final results. The additional processing includes partitioning the intermediate results into sets, scaling each intermediate result in a particular set with a scaling factor (+1 or 1) determined by the actual and hypothesized channelization codes, and combining the scaled results in each set to obtain a final result. In the STTD mode in the W-CDMA system, the final results from multiple actual OVSF code intervals can be selectively combine to obtain a recovered symbol (628).
Abstract:
A system for determining the rate at which data has been encoded in the receiver (12) of a variable-rate communications system. The data is received in symbols that are grouped in frames. When data is transmitted at full rate, the frame is filled with symbols. When the data is transmitted at less than full rate, symbols are repeated within a frame until the frame is full or the symbols are spaced apart within a frame. At an encoding rate of one fourth the full rate, for example, each symbol in the frame is repeated four times or data is transmitted one quarter of the time. The incoming frames are decoded, for example by decoder (48), and re-encoded, for example by encoder (76), at each possible data rate. A comparator, for example comparator (84), compares the re-encoded symbols with the originally received symbols and a counter, for example counter (100), counts the number of symbol errors. Each decoding process produces an indication of the quality of the decoding process which may include Cyclic Redundancy Check (CRC) results, for example CRC (120), or Yamamoto Quality Metrics. The counted errors and the quality indication comprise an error metric which is passed to a processor, for example microprocessor (56). The processor analyzes the error metric for each data rate and determines the most probable rate at which the incoming symbols were encoded.
Abstract:
In a wireless network, a primary synchronization signal and a secondary synchronization signal are sent at a predetermined bandwidth in a transmission. The predetermined bandwidth is a lowest operating bandwidth of the wireless network. Data is also sent in the transmission using an operating bandwidth greater than the lowest operating bandwidth.