Atheros Communications, Inc.

Qualcomm Incorporated

Qualcomm Atheros Inc.

Atheros, Inc.

Tao-Fei Samuel Ng

James Simon Cho

Ning Zhang

Jeffrey Scott Kuskin

Jeffrey M Gilbert

Qinfang Sun

Won-Joon Choi

Yi-Hsiu Wang

Kai Shi

Vincent Knowles Jones, Iv

Youhan Kim

Xiaoru Zhang

Deepak Dhamdhere

Fiona Cain

Sreepathy Aida

Bin Tian

Stephen Jay Shellhammer

Paul J Husted

Jialing Li Chen

Nancy Cam-Winget

Kevin Neal Hayes

Richard Mosko

Felix Bitterli

John Thomson

Sankara S Venkateswaran

Ahmed H Hassan

Sreepathy Laxmanbabu Aida

This disclosure provides methods, devices and systems for acknowledgement and retransmission, and more specifically, to methods, devices and systems that enable a secondary wireless channel to provide acknowledgements of data transmitted on a primary wireless channel concurrently with the reception of additional data on the primary wireless channel. In some implementations, a transmitting device may transmit wireless packets including multiple codewords to a receiving device via a first wireless channel. The receiving device may attempt to decode the received codewords based on primary information in the codewords. The receiving device may then transmit to the transmitting device, via a second wireless channel, a codeword acknowledgement that identifies codewords that the receiving device did not successfully decode. The transmitting device may then transmit parity information to the receiving device via the first wireless channel that aids the receiving device in decoding the identified codewords.

Acknowledgement and retransmission techniques utilizing secondary wireless channel

This disclosure provides systems, methods, and apparatus, including computer programs encoded on computer-readable media, for implementing a hybrid automatic repeat request (HARQ) protocol in a wireless local area network (WLAN). A first WLAN device may generate a first HARQ packet for transmission to a second WLAN device. The first WLAN device may determine a first basic service set (BSS) indicator and a second BSS indicator for a BSS associated with the first WLAN device and the second WLAN device. The first BSS indicator and the second BSS indicator may be indicative of a BSS identifier (BSSID) of the BSS. The first WLAN device may output the first HARQ packet for transmission to the second WLAN device. The first HARQ packet may include the first BSS indicator and the second BSS indicator in one or more fields of a physical layer (PHY) header of the first HARQ packet.

Hybrid automatic repeat request (HARQ) with basic service set (BSS) and station identification

A communication device receives at least a portion of a packet. Power is reduced to a subset of components of a communication device. The subset of components for which power is reduced is determined based, at least in part, on a length of the packet. The power is reduced for a time period based, at least in part, on the length of the packet.

Power management of communication devices

A method for reducing power consumption in a communication device. The method includes determining, by the communication device, that a packet transmitted on a communication medium is not intended for the communication device and estimating a length of the packet. If the length is greater than a first threshold but less than a second threshold, selecting a first group of components of the communication device to which to reduce power. If the length is greater than the second threshold, selecting a second group of components of the communication device to which to reduce power. The second group of components includes the first group of components. The method includes reducing power to the selected group of components.

An electronic device includes a medium access controller (MAC) to generate frames and transmitter circuitry to convert the frames to radio-frequency (RF) analog signals for transmission. The MAC is to initiate frame generation at a time that precedes initiation of RF analog signal transmission by a specified time period. In a first mode, the MAC is to generate a dummy frame during a first portion of the specified time period and to initiate generation of a transmit frame during a subsequent second portion of the specified time period. Also in the first mode, the transmitter circuitry is to convert the dummy frame into a first analog signal, discard the first analog signal, convert the transmit frame into a second analog signal, and transmit the second analog signal.

Transmitter warm-up using dummy frame generation

This disclosure is directed to wireless or wired multiple-input multiple-output communication systems, in which a transmit symbol vector and a set of soft decision metrics are estimated using a reduced complexity maximum likelihood (ML) detection method based on a receive symbol vector and a QR decomposition of a set of permuted channel matrices. The QR decomposition can be performed by a series of CORDIC operations. Preferably, the modified receive vector and upper triangular matrix streams are scaled by a weighting vector to help compensate for transmit and receive side noise. Also preferably, the soft decision metric set related to the reliability of transmitted bits is normalized.

System and method for providing reduced complexity maximum likelihood MIMO detection

In a multiple-input multiple-output communication system, a transmit symbol vector and a set of soft decision metrics may be estimated using a reduced complexity maximum likelihood (ML) detection method based on a receive symbol vector and a QR decomposition of a set of permuted channel matrices. The reduced complexity ML detection method may use a different permuted channel matrix to estimate each transmit symbol in a transmit symbol vector. A set of error distances may be calculated for the estimated transmit symbol vector, each error distance calculated choosing a different value from a signal constellation subset for a transmit symbol in the estimated transmit symbol vector. A soft decision metric may be calculated using the elements from the set of error distances. In some embodiments the transmit symbols of a transmit symbol vector and the soft decision metrics for each transmit symbol may be determined in parallel.

Apparatus and method for reduced complexity maximum likelihood MIMO detection

Current OFDM systems use a limited number of symbols and/or sub-channels to provide approximations for channel estimations and pilot tracking, i.e. phase estimations. For example, two training symbols in the preamble of a data packet are used to provide channel estimation. Four of the fifty-four sub-channels are reserved for providing phase estimation. However, noise and other imperfections can cause errors in both of these estimations, thereby degrading system performance. Advantageously, decision feedback mechanisms can be provided to significantly improve channel estimation and pilot tracking in OFDM systems. The decision feedback mechanisms can use data symbols in the data packet to improve channel estimation as well as data sub-channels to improve pilot tracking.

Decision feedback channel estimation and pilot tracking for OFDM systems

A method for encrypted communications between a first transceiver and a second transceiver is provided. The method includes sending from a first transceiver to a second transceiver a request to initiate derivation of a new encryption key. The request to initiate a new encryption key derivation includes an exchange threshold indicative of when the new encryption key is to be used to encrypt communication packets.

Key refresh at the MAC layer

A key-caching system retrieves actively used keys from a relatively fast cache memory for fast processing of wireless communications. Additional keys are stored in relatively slow system memory that has high storage capacity. As keys become needed for active use, the keys are retrieved from the system memory and stored in the cache memory. By using active memory for keys actively being used, system performance is enhanced. By using system memory for keys not being used, a greater number of keys are available for transfer to the cache and subsequent active use.

Key caching system

In a wireless local area network (WLAN), receiving or transmitting signals having multiple modulation schemes can require the use of multiple clock rates. Providing these multiple clock rates significantly increases silicon area and power consumption, both of which are highly undesirably in a wireless device. A sequencing interpolator can advantageously reduce the number of clock rates by receiving signals at a first rate and outputting signals at a second rate. The sequencing interpolator can include a multiplexer network that selectively determines which coefficients are applied to certain signals. Coefficients are chosen to ensure that an error in a frequency domain is within a given tolerance. The multiplexer network can be controlled by a counter value. At a predetermined count, the interpolated output signal is discarded and the counter is reset.

Receiving and transmitting signals having multiple modulation types using sequencing interpolator

A Hardware MAC (Media Access Control) unit implements time-critical functions according the 802.11 standard for telecommunications, thereby enhancing system performance. The MAC layer includes three sub-layers: MLME (MAC Sublayer Management Entity), which connects the MAC unit with the host CPU, FTM (Frame Transition Manager), which connects the MAC unit with the network, and FLPM (Frame Level Protocol Manager), which internally connects the MLME sub-layer with the FTM sub-layer. In particular, the FLPM manager includes time-critical and non-time-critical functions that are customarily implemented in software on the MAC by a MAC CPU (Central Processing Unit). The hardware MAC implements time-critical FLPM functions in hardware on the MAC and implements non-time-critical FLPM functions in software on the host CPU so that requirements for processing software on the MAC preferably may be altogether eliminated or alternatively may be substantially reduced.

Hardware MAC

A method of queue management includes: adding entries having a first priority to a first software queue; adding entries having a second priority to a second software queue; reading entries from the first software queue to a physical queue; at a threshold time, flushing entries from the physical queue; after the act of flushing the physical queue, reading entries from the second software queue to the physical queue until a termination criterion is satisfied; after the termination criterion is satisfied, reading entries from the first software queue to the physical queue; and transmitting entries from the physical queue to a network.

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Fremont, CA, United States of America

Tao-Fei Samuel Ng