摘要:
The present invention discloses an apparatus for initial synchronization and cell search in a CDMA system based on multipath energy window. The apparatus perform initial synchronization and adjacent cell search by using multipath energy window based on the processing method of multipath energy window. The apparatus can be implemented based on a parallel correlator bank. This invention also provides the application of the apparatus to a coherent spreading receiver.
摘要:
The Spread Spectrum integration coherent receiver of the invention employs a time division multiplexing correlator bank and thus obtained coherent channel evaluator as a core. The receiver can execute initial PN synchronization, RAKE diversity coherent combination, AFC and adjacent cell search and combination receipt, and soft handoff. Further, “part capture in parallel based on slide energy window” and “tracking loop based on energy window barycenter” are introduced into the receiver of the invention, thereby simplifying the structure of the RAKE receiver. The receiver is capable of overcoming multipath fading, ensuring the RAKE receipt performance.
摘要:
The present invention discloses a method for pilot channel tracking based on multipath channel barycenter tracking loop, comprises steps of evaluating multipath fading channel parameters, calculating the barycenter of a multipath energy window, and loop filtering and adjusting the phase of spread spectrum sequence codes. The method of the invention does not need to individually track each delay path, thereby improving the tracking performance and timing recovery stability of a spread spectrum receiver. Only a multipath channel evaluator and a multipath energy window barycenter calculating means are used to track PN signals from a plurality of signal sources, thereby reducing hardware. Thus, a novelty coherent spread spectrum receiver can be constituted by cooperating with other parts.
摘要:
The present invention relates to a method and an apparatus for adjusting an average interval of channel estimation dynamically based on Doppler-shift. The method comprises the steps of estimating Doppler-shift by using level cross rate (LCR) according to differently moving speeds of mobile terminals, determining the optimal average interval of channel estimation based on the relationship between the existing Doppler-shift and the optimal average interval of channel estimation, dynamically adjusting the average interval of channel estimation according to the determined the optimal average interval of channel estimation to make the coherent receiver obtain the optimal estimation performance at different moving speeds. The apparatus of the present invention comprises a channel estimation module, a valid/strongest finger selection module, a RAKE demodulation and combining module, a RAKE output decision module, an LCR detection and Doppler-shift estimation module, a Gaussian noise power estimation module, a strongest path signal power estimation module, and an optimal average interval calculation module.
摘要:
An automatic frequency correction (AFC) apparatus used for CDMA multipath fading channels comprises a frequency-offset evaluator, an automatic frequency correction loop filter and a carrier frequency adjuster. The present invention provides a “multipath energy window” designing method for the non-determinacy of multipath signals in mobile communication environment. Frequency-offset information can be extracted from the multipath energy window by a simple calculation and evaluated by a maximal SNR weight process. This invention also provides a step-variable accumulation adjusting method and greatly improves the response speed of the AFC apparatus as compared with a conventional loop filter, whereby supplies better AFC required for CDMA mobile terminals.
摘要:
The present invention relates to a method and an apparatus for adjusting an average interval of channel estimation dynamically based on Doppler-shift. The method comprises the steps of estimating Doppler-shift by using level cross rate (LCR) according to differently moving speeds of mobile terminals, determining the optimal average interval of channel estimation based on the relationship between the existing Doppler-shift and the optimal average interval of channel estimation, dynamically adjusting the average interval of channel estimation according to the determined the optimal average interval of channel estimation to make the coherent receiver obtain the optimal estimation performance at different moving speeds. The apparatus of the present invention comprises a channel estimation module, a valid/strongest finger selection module, a RAKE demodulation and combining module, a RAKE output decision module, an LCR detection and Doppler-shift estimation module, a Gaussian noise power estimation module, a strongest path signal power estimation module, and an optimal average interval calculation module.
摘要:
For a demand of high speed, low cost and low power loss short distance wireless communication, a high-speed sampling and low-precision quantification pulse ultra-wideband wireless communication method is provided. A baseband narrow pulse sequence is generated at a transmission end using the digital technology by the method, and is transmitted after modulating amplifying and filtering and amplifying at a reception end, after the digital-signal processing of synchronizing, channel estimating, related detecting, and channel decoding, tec, is performed for the quantified data, the transmission information is retrieved. Comparing with the present carrier mechanism UWB wireless communication technology, the method does not need the complex radio frequency processing of orthogonal modulation/demodulation and frequency spectrum moving, etc, the quantification precision of analog-to-digital conversion is also decreased greatly, so the cost and power loss are greatly decreased; comparing with the present pulse mechanism UWB wireless communication technology, the method provided by the present invention greatly increase the data transmission rate, and increases the stability, reliability and integration.
摘要:
A detection method of space domain maximum posteriori probability (MAP) in a wireless communication system is a kind of detection technique of space domain MAP in a multi-aerial wireless communication system, which makes the detection of iteration soft interference elimination for the interference signals in the other moments, and makes the MAP detection or the simplified MAP detection for the all signals in current time and space domain. It includes the steps of: taking a fading block as a unit; the received signals are matched and combined in time domain and space domain, and calculating an equivalent channel matrix; making the sequence detection, calculating estimation and variance of the signals before the ending of detecting internal iteration; when the internal iteration detection finishes, the result is outputted, or is outputted after hard decision.
摘要:
A pilot and channel estimation method for SDMA MIMO transmission downlink is provided in the present invention, and the method provides possibility for saving the orthogonal pilot resources; the pilot signals of different users in the transmitting antenna domain can occupy the same time-frequency resources, and thereby the pilot overhead of system resources can be reduced greatly; the method includes: for the MIMO transmission downlink that employs pre-coding for SDMA, taking the quantity of orthogonal pilot resources occupied by the users in the pre-coding domain as the number of data streams that can be transmitted or the number of spatial dimensions occupied first, at the transmitting end of the base station; then, performing SDMA transmission pre-coding for the orthogonal pilots in the pre-coding domain in the same way as the data signals, to obtain the pilot signals of the users in the transmitting antenna domain; wherein, the pilots of the users in the pre-coding domain can be orthogonal in the frequency domain or code domain, and the pilots of different users in the pre-coding domain can be identical or not identical to each other; the pilot signals of different users in the transmitting antenna domain can occupy the same time-frequency resources.
摘要:
For a demand of high speed, low cost and low power loss short distance wireless communication, a high-speed sampling and low-precision quantification pulse ultra-wideband wireless communication method is provided. A baseband narrow pulse sequence is generated at a transmission end using the digital technology by the method, and is transmitted after modulating amplifying and filtering and amplifying at a reception end, after the digital-signal processing of synchronizing, channel estimating, related detecting, and channel decoding, tec, is performed for the quantified data, the transmission information is retrieved. Comparing with the present carrier mechanism UWB wireless communication technology, the method does not need the complex radio frequency processing of orthogonal modulation/demodulation and frequency spectrum moving, etc, the quantification precision of analog-to-digital conversion is also decreased greatly, so the cost and power loss are greatly decreased; comparing with the present pulse mechanism UWB wireless communication technology, the method provided by the present invention greatly increase the data transmission rate, and increases the stability, reliability and integration.