Telefonaktiebolaget Lm Ericsson (publ)

Tor Bj&ouml;rn Minde

Johan Nystr&ouml;m

Fredrik Klas Jansson

Roar Hagen

Tomas Svensson

Anders Tomas Uvliden

Per Anders Karlsson

Per Gunnar Heikkil&auml;

A multi-channel signal encoder includes an analysis part with an analysis filter block having a matrix-valued transfer function with at least one non-zero non-diagonal element. The corresponding synthesis part includes a synthesis filter block ( M) having the inverse matrix-valued transfer function. This arrangement reduces both intra-channel redundancy and inter-channel redundancy in linear predictive analysis-by-synthesis signal encoding.

Multi-channel signal encoding and decoding

A channel optimized vector quantization apparatus includes a device for weighting a sample vector x by a weighting matrix A and a device for weighting a set of code book vectors &ccirc;,by a weighting matrix B. Device form a set of distance measures &lcub;d,(Ax,B&ccirc;,)&rcub; representing the distance between the weighted sample vector Ax and each weighted code book vector B&ccirc;,. Other device form a set of distortion measures &lcub;,(x)&rcub; by multiplying each distance measure by a channel transition probability P,that an index r has been received at a decoder when an index i has been sent from an encoder and adding together these multiplied distance measures for each possible index r. Finally device determine an index i,corresponding to the smallest distortion measure,(x) and represents the sample vector by this index i,.

Distance and distortion estimation method and apparatus in channel optimized vector quantization

An improved method and system of measuring the perceived speech quality in mobile telecommunications networks is disclosed herein. In an embodiment of the invention, the method uses both radio link parameters and an objective measuring technique performed on received signals to estimate the speech quality perceived by the end-user. A radio link processing stage extracts temporal information from a set of available radio link parameters such as the BER, FER, RxLev, handover statistics, soft information, and speech energy. Concurrently, a speech processing stage is used to process a sequence of original signals and received signals, obtained from the output of a telecommunications system. The signal sequences are processed by an objective measuring technique such as Perceptual Speech Quality Measure (PSQM). The outputs from the radio link processing and speech processing stages are utilized to calculate an estimate for speech quality. Furthermore, a weight may be given to radio link processing and speech processing in accordance with their performance under various conditions such that the overall speech quality is calculated with respect to the best approach.

Speech quality measurement based on radio link parameters and objective measurement of received speech signals

In a digital cellular radio communication system, a base station selects a speech/channel encoding mode based on measurements of the local radio environment. The mobile station determines the selected mode by trial decoding possible modes to find the most probable mode and uses the same mode for transmission to the base station on the return link. The coding gain/loss obtained by this mode switching may be used to adjust the output power of transmitters, thereby reducing the overall interference level in the system.

Growing community of inventors

Gammelstad, Sweden

Tor Björn Minde

Growing community of inventors

Gammelstad, Sweden

Tor Bj&ouml;rn Minde

Tor Björn Minde