37results about "Network synchronisation" patented technology

A code division multiple access wireless network (10) comprises a plurality of base stations (11-14) which operate asynchronously with respect to one another. A set of scrambling codes are allocated to the base stations for scrambling signals transmitted from the base stations. A node (30) of the wireless network receives (102) a first type of measurement report from wireless terminals (20), which comprises an observed time difference measurement acquired by the wireless terminal (20) for a signal received from one of an active set of base stations (11, 12, 13) that currently serve the wireless terminal. A timing reference is determined (103) for each of the base stations using a plurality of the observed time difference measurements. A second type of measurement report is received (105) from a wireless terminal (20) which comprises an observed time difference measurement acquired by the wireless terminal for a signal received from a base station (14) which is not currently serving the wireless terminal and a scrambling code of the received signal. An identity of the base station (14) in the second type of measurement report is determined by using the scrambling code of the signal received from the base station (14) which is not currently serving the wireless terminal and the observed time difference measurement in the second type of measurement report and the determined timing reference for that base station.

Data is accessed from a network via a wireless communication link. A determination is made as to whether payload data has been received from a subscriber's terminal. If so, then a request is sent for a first set of traffic channels, and the payload data is transmitted over the first set of traffic channels.

A code division multiple access wireless network (10) network includes a plurality of base stations (11-14) operating asynchronously with respect to each other. Sets of scrambling codes are assigned to the base stations in order to scramble signals transmitted from the base stations. A node (30) of the wireless network receives (102) a first type of measurement report from a wireless terminal (20), the first type of measurement report includes , 13) Observational time difference measurements of signals received by a base station in the active set. A timing reference is determined (103) for each base station using the plurality of observed moveout measurements. receiving (105) from a wireless terminal (20) a second type of measurement report comprising observed time difference measurements collected by the wireless terminal for signals received from base stations (14) not currently serving the wireless terminal and the scrambling code of the received signal. By using the observed time difference measurement in the second type of measurement report and the scrambling code of the signal received from the base station (14) not currently serving the wireless terminal and the determined timing reference for this base station, it is determined The identity of the base station (14) in the measurement report of .

The invention belongs to the technical field of communication and satellite navigation, and in particular relates to a weighted lp correlation synchronization method (p=1 or 2). According to the method, a special weight function is used, and lp correlation coefficients are weighted to effectively suppress the influence of a multipath effect on a traditional lp correlation synchronization algorithm. The analysis shows that the weight function used in the invention has the effect of time domain filtering and can filter out pseudo-peak generated by the multipath effect. In particular, when p is equal to 1, the algorithm provided by the invention has strong robustness to heavy tail distribution noise. A simulation result shows the correctness and validity of theoretical analysis, and shows that in orthogonal frequency division multiplexing (OFDM) and code division multiplexing (CDMA) systems, the method has higher synchronization accuracy and performance than the existing algorithms.

An improved spread spectrum communication system includes a transmitter and a receiver utilizing a pilot channel for the transmission of pure rather than modulated PN codes for code acquisition or tracking purposes with a lower bit error rate. The pilot signal is used to obtain initial system synchronization and phase tracking of the transmitted spread spectrum signal. At the transmitter side, a Walsh code generator, a Walsh modulator, a first PN code generator, a first band spreader, a second band spreader, finite impulse response filters, digital-analog converters, low-pass filters, an intermediate frequency mixer, a carrier mixer, a band-pass filter are used to transmit a spread spectrum signal. At the receiver side, a corresponding band-pass filter, a carrier mixer, an intermediate-frequency mixer, low-pass filters, analog-digital converters, a second PN code generator, an I channel despreader, a Q channel despreader, a PN code synchronization controller, a Walsh code generator, a first Walsh demodulator, a second Walsh demodulator, accumulator & dump circuits, a combiner, and a data decider are used to demodulate a received spread spectrum signal