Cambridge Silicon Radio Limited

Qualcomm Technologies International, Ltd.

Csr Technology Inc.

Qualcomm Incorporated

Hong Wan

Erik David Lindskog

Naveen Kumar Kakani

Fei Tong

Raja Banerjea

Ian Charles Blair

Benjamin Tarlow

Rainer Herberholz

Ben J Tarlow

Simon Chang

To determine a location of a client device in a wireless network having at least first and second network devices, with known locations, one of the network devices transmits a message to the other network device and the other network device responds with an acknowledgement message. A client device receives the message and the acknowledgement message as well as respective times indicating actual times at which the message and the acknowledgement message were processed by one of the first and second network devices. The client device determines its location based on the times at which it received the message and the acknowledgement message and the difference between the actual processing times. This location may be refined by determining an angle between the client device and at least one of the network devices having multiple antennas and being configured for steered beam communications.

Method for determining location of wireless devices

This invention is related to a low-complexity MIMO detector in a wireless communication system with near optimal performance. An initial symbol estimation is performed for a received symbol vector. The soft information of the received symbol vector can be more accurately calculated using every candidate symbol vector of a combined set of candidate symbol vectors, wherein the combined set is generated based on the initial estimation. By combining aspects of both the linear detection and the ML detection, the complexity of the proposed detector becomes orders of magnitude lower than that of a ML detector, but the performance is very close to that of an ML detector.

Near maximum likelihood spatial multiplexing receiver

A method for determining the location of a client device in a wireless network having at least a first and a second other network devices each with a known location is disclosed. The first other network device and the second other network device each transmit to the other two messages, and each acknowledges the first message sent by the other. The client device receives these messages, the acknowledgement messages, and respective timing information indicating the actual time when the message and the acknowledgement message were processed by the first and the second other network devices. The client device utilizes the difference between the actual processing times to determine its location. This method allows the location determination to be independent of the accuracy of the time of flight between the first other network device and the second other network device.

Method for determining location of wireless devices based on information within messages received from other network devices

Methods for determining a location of a client device in a wireless network having at least a first other network device with a known location are disclosed. Transmission-to-self calibrations are performed at the first other network device and/or the client device to determine RF group delay of the first other network device and/or the client device. The client device receives messages and acknowledgements from the other network devices and determines its location based on information received including the time at which it received the messages, the acknowledgements and the RF groupdelay of the first other network device. As such, the location calculation can be refined by accounting for the RF group delays of the first other network device and/or the client device.

This invention is related to a low-complexity MIMO detector in a wireless communication system with near optimal performance. Initial symbol estimation is performed for a transmitted symbol vector. The soft information of the transmitted symbol vector can be more accurately calculated by deemphasizing the LLRs associated with symbols belonging to weak channels that may suffer from poor initial estimation. By combining aspects of both the linear detection and the ML detection, the complexity of the proposed detector becomes orders of magnitude lower than that of a ML detector, but the performance is very close to that of an ML detector.

Decision feedback solution for channels with low signal to noise ratio

There is disclosed a receiver and associated methods in which a received signal can be sampled at the symbol rate rather than oversampled. This reduction in the sampling frequency compared with conventional receivers lowers power consumption. Quality metrics in receiving the data (e.g. packet error rate, etc) are not adversely affected by setting a programmable phase shift in the sampling frequency. The programmable shift can be selected through a calibration process using a known sequence of symbols, such as the short training field in 802.11 standards.

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Santa Clara, CA, United States of America

Hong Wan