Telefonaktiebolaget Lm Ericsson (publ)

Niklas Stenström

Bengt Lindoff

Anders Khullar

Jakob Singvall

William Camp

The invention provides improved suppression of co-channel interference (CCI) in a wireless cellular communications system where at least two base stations use the same transmit frequency. The method according to the invention uses the difference in synchronization times between the home signal and the CCI signal to suppress the CCI signal. The method uses a modified known method of estimating time of arrival (TOA) to estimate sync positions for the CCI signal. This enables the use of interference cancelling methods in communications systems using un-synchronized base stations. Receiver performance is improved, which in turn improves data throughput and received speech quality, since interfering signals from base stations using the same frequency can be suppressed.

Co-channel interference suppression by estimating the time of arrival (TOA)

A mobile station adapted to be used in a radio communications system includes a receiver apparatus adapted to receive blocks of distorted information bits at a first rate from a transmitter via a communications link, and a first detecting apparatus adapted to detect information bits from the distorted information bits. The mobile station also includes a second detecting apparatus adapted, when the quality of the received blocks of information bits is above a given level, to detect information bits from the distorted information bits using fewer computation resources than the first detecting apparatus.

Mobile station, a method of transmitting electronic information, and a communications system

A digital communication receiver communicates with a digital communication transmitter across a communication channel and has: a channel estimator, which provide a channel estimate of the communication channel based on a received signal; an equalizer, which estimates a sequence of transmitted symbols and provides a sequence of decided symbols based on the received signal and the channel estimate; and a channel tracker, which produces an updated channel estimate based on the received signal and the decided symbols, and which supplies the updated channel estimate to the equalizer. The digital communication receiver has a controller, which receives channel quality indicative data associated with an output from the equalizer, determines whether these data fail to meet a predetermined criterion, and, if so, supplies an enabling control signal to the channel tracker.

Digital communication receiver and a method for the operation thereof

The invention relates to: A method for estimating residual noise in the frequency range () of a desired part () of a signal to a corresponding apparatus and to a mobile telephone utilizing the method. The object of the present invention is to generate a measure for the residual noise in a signal. The problem is solved in that the amplitude of the signal () comprising the noise is modified, and the signal () is combined with the modified signal () to create a noise estimation measure (). The invention may e.g. be used in digital radio communications systems to contribute to the monitoring of link quality and therefore to improve payload throughput. One of the advantages of the invention is that an indication of link quality at an early stage in the receiver is provided.

Method and an apparatus for estimating residual noise in a signal and an apparatus utilizing the method

A method and apparatus for processing a received signal containing a desired burst and a co-channel interferer burst are disclosed. The invention includes receiving the received signal from a front end receiver. A time offset between the desired burst and the co-channel interferer burst is detected. A detection procedure is then selected based on the time offset between the desired burst and the co-channel interferer burst. Preferably, one of three detection procedures is selected based on the time offset detected and optionally the signal strength of the co-channel interferer burst. If a first or second time offset is detected, then a joint detection or an iterative detection procedure is selected and performed, respectively. Finally, if a third time offset is detected or if the co-channel interferer has a low signal strength, then a conventional detection procedure is selected and performed.

Co-channel interference canceller

Methods of receiving communications signals can include generating a received analog signal including energy corresponding to communications transmitted from a remote transmitter, and performing an analog-to-digital conversion of the received analog signal to provide a received digital signal. The received digital signal can be digitally filtered using a first digital filter having a first bandwidth to provide a first filtered digital signal, and the first filtered digital signal can be processed to provide an estimate of the communications transmitted from the remote transmitter. The received digital signal can be digitally filtered using a second digital filter having a second bandwidth to provide a second filtered digital signal wherein the second bandwidth is greater than the first bandwidth, and a signal characteristic of the second filtered digital signal can be measured. Related receivers are also discussed.

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Helsingborg, Sweden

Niklas Stenström