Techniques for canceling pilot interference in a wireless (e.g., CDMA) communication system. A received signal typically includes a number of signal instances (i.e., multipaths). For each multipath desired to be processed, the other multipaths act as interference on the desired multipath. If the pilot is generated based on a known data pattern (e.g., all zeros) and covered with a known channelization code (e.g., a Walsh code of zero), then the pilot in an interfering multipath may be estimated as the spreading sequence at a time offset corresponding to the arrival time of that multipath. The pilot interference from each interference multipath may be estimated based on the spreading sequence for the interfering multipath and the despreading sequence for the desired multipath. The total pilot interference from a number of interfering multipaths may be subtracted from the data component in the desired multipath to provide pilot-canceled data having improved performance.

Method and apparatus for canceling pilot interference in a wireless communication system

According to a first broad aspect of the present invention, there is provided a novel communication system having a forward link comprising: at least one base station which transmits multiple radio frequency (RF) signals; and a mobile station, the mobile station including: a receiver for receiving the RF signals; means for converting the RF signal to an intermediate frequency (IF) signal; means (704) for sampling the IF signal to generate a digital signal, the digital signal having a data component; means (712) for canceling co-channel and or cross-channel interference in the digital signal by projecting the IF signal into a subspace orthogonal to a subspace of the interference component and multiplying this projection with the digital signal; and means (710) for acquisition and tracking of the digital signal.

Interference cancellation in a signal

A hierarchical cell structure (HCS) cellular communications system includes a macro cell encompassing a smaller micro cell that employ the same frequency band. The macro cell includes a macro cell base station, and the micro cell includes a micro cell base station. An uplink communication cell boundary between the macro cell and the micro cell is established, and a downlink communication cell boundary between the macro cell and the micro cell is established. A radio network controller determines whether a condition exists in the HCS system which indicates that the uplink and downlink micro cell boundaries should be unbalanced. If the condition is met or exists, the power and/or antenna beam tilt of a downlink transmission from the micro cell base station is reduced to unbalance the uplink and downlink micro cell boundaries. Alternatively, the radio network controller may employ an offset value to mathematically reduce mobile detected pilot power levels associated with the micro base station.

Mobile communications in a hierarchical cell structure

An interference canceller comprises a composite interference vector (CIV) generator configured to produce a CIV by combining soft and/or hard estimates of interference, an interference-cancelling operator configured for generating a soft projection operator, and a soft-projection canceller configured for performing a soft projection of the received baseband signal to output an interference-cancelled signal. Weights used in the soft-projection operator are selected to maximize a post-processing SINR.

Advanced Signal Processors for Interference Cancellation in Baseband Receivers

The present invention is directed to signal cancellation in spread spectrum communication systems (100). In particular, the present invention provides method and apparatus (120, 128 and 132) for selectively canceling interfering signals, even where symbols to be canceled do not align with symbols associated with a desired signal path. Furthermore, the interference cancellation provided by embodiments of the present invention is capable of functioning to remove interference associated with channels utilizing a symbol length that is different than the symbol length of a desired signal path. In accordance with a further embodiment of the present invention, method and apparatus for efficiently calculating projections to enable signal cancellation are provided.

Method and apparatus for interference suppression with efficient matrix inversion in a DS-CDMA system

The invention relates to a TDMA cellular radio system, and a method of allocating available frequency bands to different cells in a TDMA cellular radio system wherein at least some of the receivers within the system employ interference cancellation methods for cancelling the effects of co-channel interference in a desired signal. To enable an efficient utilization of interference cancellation methods and the resulting capacity increase in the system, the frequency bands available for the cellular radio system are, according to the method of the invention, so allocated to different cells that groups (50-55) of adjacent service areas are formed in the system, each group employing the same frequency band within the service areas, whereby at least one co-channel signal interfering with the desired signal is significantly stronger than other co-channel interfering signals.

Method of allocating frequency bands to different cells, and TDMA cellular radio system

Method of allocating frequency bands to different method of allocating frequency bands to different cells, and tdma cellular radio system cells, and tdma cellular radio system

Gandini Giulio

Papers

Method of allocating frequency bands to different cells, and TDMA cellular radio system

Method of allocating frequency bands to different method of allocating frequency bands to different cells, and tdma cellular radio system cells, and tdma cellular radio system