摘要:
A wireless transmit-receive unit includes an antenna, detection circuitry configured to detect a pseudorandom (PN) offset of a pilot signal received by the antenna while the antenna is adapted to an omnidirectional receive pattern, and monitoring circuitry configured to monitor a received signal strength of the pilot signal as a directional receive pattern of the antenna is steered in order to determine an azimuth angle of the directional pattern that maximizes the pilot signal at the detected PN offset.
摘要:
A method for generating a preamble signal for a wireless communication system including the step of combining a plurality of different short PN sequences into a long PN sequence, wherein one of the plurality of short PN sequences includes information that is configured for coarse timing synchronization, and the long PN sequence includes information that is configured for fine timing synchronization.
摘要:
The present invention relates to a method (and corresponding device) of detecting a first signal in a received signal using a pattern, the received signal comprising at least one signal group, each signal group comprising a number of signal symbols, the pattern comprising at least one pattern group, each pattern group comprising at least a number of pattern symbols, wherein the method comprises the steps of for each signal group multiplying each signal symbol with a corresponding pattern symbol of a pattern group and deriving a sum of the products of multiplication, applying a weight factor of one or more weight factors to each sum giving a weighted sum, where said one or more weight factors are selected to preserve an orthogonality relation of said pattern symbols of the least one pattern group, and determining if a signal is detected or not based on said one or more weighted sums.
摘要:
A method for controlling integration for a CDMA signal and a receiver implementing the same. In accordance with the present invention, non-coherent and even coherent integration periods for a received signal are dynamically and adaptively controlled depending upon the condition of the received signal. The integration period can be very short when signal strength is strong and no blocking exists; while it can be extended to be longer when the signal strength is weak or there is a blocking. Therefore, it is possible to keep locking even under bad circumstances. In addition, the fix time can be shortened when the signal strength is very strong.
摘要:
An embodiment generally relates to a method of processing direct-sequence spread spectrum signals for temporal alignment between a received direct sequence spread spectrum (DSSS) signal and a local reference signal. The method includes receiving the received DSSS signal with bandwidth to resolve at least N samples per code chip and de-spreading the received DSSS signal to recover an elemental waveform within the received DSSS signal for an interval greater than one code chip interval as a first processing stage. The method also includes determining a discriminator value based on the elemental waveform as a second processing stage and operating a delay-locked loop based on the discriminator value to adjust an alignment between the received DSSS signal and the local reference signal.
摘要:
A searcher for a mobile station of a cellular telephony network. Pilot signal from nearby base stations are correlated with a pseudonoise sequence inside a search window, using a bank of correlators. Each correlator is assigned a different delay, from among a sequence of delays in the window. At each delay, correlation is performed initially for a first dwell time. If the resulting correlation value exceeds a threshold, the correlation is continued for a second dwell time. Otherwise, the correlator is set to the next delay in the sequence. Only the outputs of second dwell correlations are used to identify the nearest base station. Some correlators may perform first dwell correlations at new delays in the window at the same time that other correlators are still performing second dwell correlations at old delays in the window.
摘要:
A cell-searching method and device for a mobile terminal in TDD-CDMA system, in which the mobile uses the special power pulse of using the downlink pilot slot (DwPTS) to acquire coarse synchronization before using conventional correlation cell searching to refine the search. Due to the coarse synchronization, the conventional correlation cell search can be limited to a narrow time window. So the cell searching complexity and searching time in the TDD-CDMA system, especially TD-SCDMA decrease greatly.
摘要:
A CDMA baseband receiver includes a first correlating unit, a long code phase candidate outputting section and a long code determining section. The first correlating unit calculates first correlation values from a spread modulation signal and a short code which is common to base stations. The long code phase candidate outputting section outputs selected long code phase candidates corresponding to ones selected from the first correlation values, based on the spread modulation signal, and determined long codes. The selected long code phase candidates are other than long code phase candidates for known ones of the base stations. The long code determining section generates the determined long codes for unknown ones of the base stations from the spread modulation signal, the short code, and long codes generated based on the selected long code phase candidates. Each long code is peculiar to one base station.
摘要:
Multi-path effects are common in mobile communications. When coupled with spread-spectrum signals utilizing spreading code sequences, detection of more than one multi-path signal becomes a necessity in order to output a clean signal with little loss. In accord with the invention, a spread-spectrum sliding matched-filter searcher system comprises a partial matched-filter that receives the input spread-spectrum signal. The searcher matches samples of the input signal with a tap length m of the reference code and produces a first correlation value. The first correlation value is compared to a first threshold. When it equals or exceeds the first threshold, the first correlation value is integrated to produce a second correlation value. This second value is compared with a second threshold, which if met signifies the detection of the multi-path signal. The process is repeated until all significant multi-path signals are detected. This design of the present invention is flexible in nature because the searcher can be programmed to act like a matched-filter, a correlator, or a combination of both while significantly improving the search time and reducing the amount of hardware and complexity characteristic of a matched-filter.
摘要:
The present invention discloses a cell search method for a CDMA system, using a three-stage cell search. The method comprises matching an incoming signal from the base station, wherein the frequency of the incoming signal having an uncertain range; over-sampling the incoming signal N times against a chip rate and outputting the N over-samples; down-sampling the incoming signal and outputting N over-samples to a first stage, a second stage and a third stage. The first stage further comprises selecting a first group of slot boundaries as a first group of candidates after pre-selection, and the first group of candidates transmitting to a deciding selection stage of the first stage and the second stage to be continuously processed. The cell search method of the present invention can be used to reduce the effect of clock offset on the performance of cell search and to accomplish fast cell search.