Abstract: The present invention proposes methods for facilitating and improving the performance of MU-MIMO transmission in wireless communication systems. Each user within a MU group inserts an inter-user interference indication field in its acknowledgement packet. The inter-user interference indication field includes signal-to-interference-noise-ratio (SINR) and interference source information. The MU-MIMO transmitter extracts inter-user interference indication feedback and improves subsequent MU-MIMO transmission. Feedback of the inter-user interference information such as SINR and interference source allows efficient link adaptation, smarter user selection, channel re-sounding selection, and fine-tuning of precoding matrix.

Abstract: A method of monitoring channel-sounding quality for VHT WiFi devices is provided. A mobile station (the receiver) receives a sounding signal transmitted from an access point (the transmitter) over one or multiple sub-channels of a wide channel in a wireless network. The receiver performs channel estimation and determines an estimated channel response matrix. The receiver then calculates sounding quality for each valid sub-channel by computing an estimation error of the received sounding signal based on the estimated channel matrix. The receiver transmits a feedback message to the transmitter. The feedback message contains sounding quality information derived from the calculated channel sounding quality. If the channel sounding qualities for all valid sub-channels are poor, then a null VHT channel feedback frame is sent back to the transmitter.

Abstract: The method and apparatus of data communications for a transmitter in a millimeter wave network are provided. The method includes: generating a control physical layer (CPHY) preamble; generating a header, wherein the header includes a mode indicator; modulating and encoding a payload according to the mode indicator; generating a packet according to the control physical layer (CPHY) preamble, the header and the payload; and transmitting the packet.

Abstract: A method of channel estimation enhancement is provided. In a wireless communications system, a transmitting device transmits a long preamble frame comprising a first training field, a signal field, and a second training field. The signal field has a beam-change indicator bit indicates whether there is beam change between the first training field and the second training field. A receiving device receives the long preamble frame, performs a first channel estimation based on the first training field, and performs a second channel estimation based on the second training field. If the beam-change indicator bit indicates negative beam change, then the receiving device performs channel estimation enhancement by combining the first channel estimation and the second channel estimation. As a result, channel estimation performance is improved.

Abstract: The disclosed invention provides an efficient method for beam training to enable spatial multiplexing MIMO operation and spatial combining in a wireless network. The invention discloses a simple and efficient beam-training algorithm and protocol for MIMO operation that operates in high SNR condition for reliable MIMO operation. In one novel aspect, the best MIMO beam combinations are determined after TX sector sweeping and RX sector sweeping. In addition, the selection criteria includes not only signal quality, but also considers mutual interference and leakage among multiple MIMO spatial streams to improve overall MIMO performance.

Abstract: Enhanced wireless speeds are obtained using multiple transmission beams. In one example a transmitter sends data packets through an antenna array using multiple spatial beams and a plurality of analog converters. A receiver receives feedback from a remote station, the feedback including a quality measure of data packets received from the transmitter. A processor to controls transmission parameters of the transmitter using the feedback, the processor having a plurality of states, in a first channel analysis state, the processor determining a beam-forming vector for the antenna array, in a second beam search and training state, the processor determining pre-coding coefficients for the data packets, and in a third high rate transmission state, the processor providing pre-coded data packets to the transmitter for transmission, wherein the processor transitions from the third state to the first state upon receiving a reduced quality measure from the remote station.

Abstract: A method of supporting incompatible channelization in a wireless communications system is provided. A coordinating device determines a first set of physical parameters of a first wireless channel. The first set of physical parameters includes a channel bandwidth, a central frequency, a transmit power limit, and a modulation and coding scheme. The coordinating device establishes communication with a first set of communications devices over the first wireless channel. The coordinating device then broadcasts a channel-adjustment message and determines a protection period. The channel-adjustment message comprises a set of instructions on how to adjust to a second set of physical parameters of a second wireless channel. A second set of communications devices adjust physical parameters based on the channel-adjustment message. Finally, the coordinating device communicates with the second set of communications devices over the second wireless channel during the protection period.

Abstract: Enhanced wireless speeds are obtained using multiple transmission beams. In one example, a transmitter has a signal processor to receive a plurality of data streams, a plurality of analog converters each coupled to the signal processor to receive the plurality of data streams from the signal processor and to modulate the data streams onto carrier waves, and a plurality of phase shifters each coupled to an analog converter to each receive a modulated stream. A first antenna is coupled to more than one of the plurality of phase shifters to receive the modulated data stream from each phase shifter and transmit it on its respective carrier wave, and a second antenna is coupled to receive at least one modulated data stream and transmit it on its respective carrier wave.

Abstract: The present invention proposes methods for facilitating and improving the performance of MU-MIMO transmission in wireless communication systems. Each user within a MU group inserts an inter-user interference indication field in its acknowledgement packet. The inter-user interference indication field includes signal-to-interference-noise-ratio (SINR) and interference source information. The MU-MIMO transmitter extracts inter-user interference indication feedback and improves subsequent MU-MIMO transmission. Feedback of the inter-user interference information such as SINR and interference source allows efficient link adaptation, smarter user selection, channel re-sounding selection, and fine-tuning of precoding matrix.

Abstract: A method of sounding and feedback with channel quality information and reduced overhead is provided. A receiving station receives a sounding signal transmitted from an access point over multiple sub-channels of a wide channel in a wireless network. The receiving station detects channel quality based on the received sounding signal for each sub-channel. The receiving station then performs channel estimation based on the received sounding signal and thereby determining feedback information. Finally, the receiving station transmits a feedback message to the access point, the feedback message contains NULL feedback information, reduced feedback information, or channel integrity/quality indicators based on the channel quality information for each sub-channel. Based on the feedback message, the access point may repeat the sounding process, narrow the transmission bandwidth, or select only stations who have indicated uncorrupted channel sounding for MU-MMO transmission.

Abstract: A method of simultaneously providing channel quality feedback information in all valid sub-channels is provided to facilitate and improve the performance of dynamic transmission bandwidth adjustment and fast link adaptation. A receiving device receives a sounding signal over a wide channel in a wireless system. The sounding signal is transmitted from a transmitting device over multiple sub-channels of the wide channel. The receiving device estimates channel quality information based on the sounding signal for each sub-channel. The channel quality information includes estimated average SNR and recommended MCS and other channel quality metrics. The receiving device transmits a feedback message to the transmitting device. The feedback message contains the estimated channel quality information for all valid sub-channels within the transmission bandwidth.

Abstract: An open-loop fast link adaptation scheme is proposed in an OFDM system. An access point first transmits a downlink packet comprising an open-loop link metric to a wireless station. The open-loop link metric contains a transmit power of the downlink packet plus a receiver sensitivity of the access point. The wireless station measures a received signal strength indication (RSSI) value of the downlink packet. The wireless station then applies open-loop link adaptation and determines a modulation and coding scheme (MCS) based on the open-loop link metric and the RSSI value. The open-loop link adaptation scheme is especially suitable for smart meter/sensor networks as it reduces overhead and increases link capacity.

Abstract: A method of monitoring channel-sounding quality for VHT WiFi devices is provided. A mobile station (the receiver) receives a sounding signal transmitted from an access point (the transmitter) over one or multiple sub-channels of a wide channel in a wireless network. The receiver performs channel estimation and determines an estimated channel response matrix. The receiver then calculates sounding quality for each valid sub-channel by computing an estimation error of the received sounding signal based on the estimated channel matrix. The receiver transmits a feedback message to the transmitter. The feedback message contains sounding quality information derived from the calculated channel sounding quality. If the channel sounding qualities for all valid sub-channels are poor, then a null VHT channel feedback frame is sent back to the transmitter.

Abstract: A radio frequency (RF) transmitter is coupled to and controlled by a processor to transmit data. A physical layer circuit is coupled to the RF transmitter to encode and decode between a digital signal and a modulated analog signal. The physical layer circuit comprises a high rate physical layer circuit (HRP) and a low rate physical layer circuit (LRP). The low rate channels generated by the low rate physical layer circuit (LRP) share a same frequency band as a corresponding high rate channel generated by the high rate physical layer circuit (HRP).

Abstract: A radio frequency (RF) transmitter is coupled to and controlled by a processor to transmit data. A physical layer circuit is coupled to the RF transmitter to encode and decode between a digital signal and a modulated analog signal. The physical layer circuit comprises a high rate physical layer circuit (HRP) and a low rate physical layer circuit (LRP). The low rate channels generated by the low rate physical layer circuit (LRP) share a same frequency band as a corresponding high rate channel generated by the high rate physical layer circuit (HRP).

Abstract: The present invention is directed to methods and apparatus for improving error indication performance in systems employing low-density parity check (LDPC) codes. In one aspect, a method and apparatus for providing error indication based on full LDPC parity check re-encoding are provided. In an embodiment, an LDPC encoder is employed at the receiver to re-encode the parity bits. In another embodiment, the parity bits are re-encoded recursively based on information readily available at the decoder of the receiver. In another aspect, a method and apparatus for providing error indication based on partial LDPC parity check re-encoding are provided. In an embodiment, partial checksum information is determined based on the decoder output and used to provide error indication. In a further aspect, a hybrid CRC checking and LDPC parity check re-encoding approach is provided. This approach further enhances error indication performance by reducing the miss probability compared to pure LDPC parity check re-encoding.

Abstract: The present invention is directed to methods and systems for enabling secure and efficient wireless transmission of HDCP-encrypted high definition (HD) signals. In one aspect, the present invention provides methods and systems for reducing the data rate required to convey HD content to enable direct wireless transmission of HD content. In another aspect, the present invention provides methods and systems for reducing the data rate required to convey HD content that are compatible with HDCP encryption of content. In a further aspect, the present invention provides methods and systems for reducing the data rate required to convey HD content while maintaining a high quality of content.