公开(公告)号：EP1240725A1

公开(公告)日：2002-09-18

申请号：EP00990761.9

申请日：2000-12-15

申请人： Telefonaktiebolaget L M Ericsson (Publ)

发明人： PALENIUS, Torgny ,  JONSON, Martin

IPC分类号： H04B1/707

CPC分类号： H04B1/707 ,  H04B2201/70705

摘要： Code Division Multiple Access (CDMA) spreading and despreading techniques eliminate the need for frame-length chip buffers within despreading and demodulation processors in CDMA receivers. According to the invention, successive CDMA frames are transmitted with variable spreading factors and a constant spreading sequence chip rate to provide a variable data throughput rate, each transmitted frame thus including a variable number of data symbols and a variable number of rate indication symbols. During transmission, channelization spreading sequences used for higher data rate frames are guaranteed to be subsets of channelization spreading sequences used for lower data rate frames. Consequently, a CDMA despreading processor according to the invention can despread incoming data symbols as they arrive at a CDMA receiver, storing the resulting symbols to a memory which must exist irrespective of the despreading process (e.g., within a deinterleaver or error detection and correction decoder). For example, incoming chips can be despread using a minimum allowable spreading rate and, upon receiving the rate information symbols included in the incoming frame, a determination can be made as to whether despreading is complete. If it is determined that the frame was spread using the minimum allowable spreading factor, then the stored data symbols are accepted as finally despread data symbols and further reception processing continues directly. Otherwise, the stored data symbols are taken to be temporary symbols which are then combined, using the guaranteed relationships between fast and slow spreading sequences, to generate the finally despread data symbols. Advantageously, a CDMA receiver according to the invention can thus operate successfully without requiring a frame-length despreading chip buffer.

公开(公告)号：EP1166481A2

公开(公告)日：2002-01-02

申请号：EP00919221.2

申请日：2000-03-17

申请人： Telefonaktiebolaget L M Ericsson (Publ)

发明人： PALENIUS, Torgny

IPC分类号： H04J13/02 ,  H04B7/26 ,  H04Q7/38

CPC分类号： H04B7/26 ,  H04B1/7103 ,  H04J11/0023 ,  H04J13/0044 ,  H04J13/20 ,  H04W52/24

摘要： Methods and structures for quickly and accurately measuring interference associated with a received signal in a CDMA radiocommunication system are described. Interference measurement is performed by despreading a received signal using a channelization code which is reserved from a finite set of orthogonal channelization codes. The reserved code is not used (or is rarely used) for spreading traffic and, therefore, provides an estimate of the interference associated with a received signal when a receiver correlates the received signal with the reserved code.

公开(公告)号：EP1125372A1

公开(公告)日：2001-08-22

申请号：EP99971979.2

申请日：1999-11-03

申请人： Telefonaktiebolaget L M Ericsson (Publ)

发明人： ATARIUS, Roozbeh ,  ERIKSSON, H kan ,  PALENIUS, Torgny ,  CARLSSON, Torsten ,  ÖSTBERG, Christer ,  GUSTAFSSON, Kjell

IPC分类号： H04B1/707 ,  H04B17/00

CPC分类号： H04B1/7115 ,  H04B2201/70707

摘要： The present invention provides a system and method for reducing the power consumed by a RAKE receiver. In exemplary embodiments of the present invention, an environment variation estimator is implemented in a CDMA mobile station. The environment variation estimator is connected to the searcher of the RAKE receiver and provides an estimate of the rate at which the mobile station's environment is changing. By providing an estimate of the rate of change of the mobile station's environment, the duty cycle of the searcher can be optimized, thereby reducing the overall power consumed by the receiver. By also providing the estimate to the RAKE fingers, channel tracking can be improved.