Abstract: A communication device receives a physical layer (PHY) protocol data unit (PPDU). The PPDU includes i) a PHY preamble and ii) PHY data portion that includes one or more PHY midambles, and the PHY preamble includes i) an indication of a length of the PPDU, and ii) an indication of a periodicity of PHY midambles in the PHY data portion. The communication device calculates a number of PHY midambles in the PPDU using i) the indication of the length of the PPDU, and ii) the indication of the periodicity of PHY midambles. The communication device calculates a reception time for the PPDU using the calculated number of PHY midambles, and processes the PPDU using the calculated reception time.

Abstract: A first communication device receives, from a second communication device, a synchronization frame having an allocation indicator that indicates a non-overlapping allocation of pilot tones. The first communication device generates a first data frame that comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols of a non-legacy training field portion, the plurality of OFDM symbols including only pilot tones corresponding to the non-overlapping allocation of pilot tones.

Abstract: Systems, apparatuses and methods described herein provide a method for padding a signal extension of orthogonal frequency-division multiplexing (OFDM) symbols. A transceiver may obtain a plurality of data symbols for transmission, and determine that a number of information bits for a last symbol of the plurality of data symbols is not an integer value. A special padding rule may be applied to add padding bits to the last symbol. A number of coded bits for the last symbol may be determined when the number of information bits for the last symbol has changed, and the plurality of data symbols for data transmission may be encoded based on the determined number of coded bits for the last symbol.

Abstract: Systems, methods, and apparatuses are disclosed herein for aligning HE-LTFs corresponding to a plurality of users by determining a respective number of spatial streams corresponding to each user, determining a highest respective number of spatial streams of the spatial streams, and setting an alignment number of HE-LTF symbols to be equal to or larger than the highest respective number of spatial streams. For each respective user, a respective matrix of HE-LTF symbols corresponding to the respective number of spatial streams of the respective user is selected, and it is determined whether the respective matrix of HE-LTF symbols has fewer symbols than the alignment number. In response to determining that the respective matrix of HE-LTF symbols has fewer symbols than the alignment number, padding symbols may be added to the respective matrix to yield a number of HE-LTF symbols in the respective matrix that corresponds to the alignment number.

Abstract: A first communication device transmits a plurality of training signals to a second communication device via a communication channel. The first communication device receives feedback generated at the second communication device based on the plurality of training signals. The feedback includes steering matrix information for a plurality of orthogonal frequency division multiplexing (OFDM) tones and (ii) additional phase information corresponding to channel estimates obtained for the plurality of OFDM tone. The first communication device constructs, based on the steering matrix information, a plurality of steering matrices corresponding to the plurality of OFDM tones, and compensates, using the additional phase information, the plurality of steering matrices to reduce phase discontinuities between the OFDM tones. The first communication device steers, using the compensated steering matrices, at least one transmission via the communication channel to the second communication device.

Abstract: A boundary within a last orthogonal frequency division multiplexing (OFDM) symbol of a PHY data unit is determined. Pre-encoder padding bits are added to a set of information bits to generate a set of padded information bits such that the set of padded information bits, after being encoded, fill one or more OFDM symbols up to the boundary within the last OFDM symbol. The set of padded information bits are encoded to generate a set of coded bits. A PHY preamble is generated to include a subfield that indicates the boundary. The one or more OFDM symbols are generated to include (i) the set of coded information bits in the one or more OFDM symbols up to the boundary to allow a receiving device to stop decoding the one or more OFDM symbols at the boundary, and (ii) post-encoder padding bits in the last OFDM symbol following the boundary.

Abstract: A heat recovery variable-frequency multi-split heat pump system and a control method thereof. The system includes an outdoor unit and at least two indoor units. The system is a three-pipe heating recovery multi-split heat pump system designed on the basis of a four-way reversing valve, and one indoor unit thereof is provided with two electronic expansion valves and two heat exchangers so that any indoor unit in the system can operate independently under three working conditions of refrigeration, heating or heat recovery dehumidification. Under multi-split condition, the system can operate under six working conditions, namely, the full-refrigeration working condition, the full-heating working condition, the common-heat-recovery working condition, the common-heat-recovery-dehumidification working condition, the heat recovery dehumidification-refrigeration-combination working condition and the heat recovery dehumidification-heating-combination working condition.

Abstract: A first communication device generates and transmits a wakeup packet configured to cause a wakeup radio of a second communication device to prompt a wireless local area network (WLAN) network interface device of the second communication device to transition from a low power state to an active state. The wakeup packet is generated to include i) a WLAN legacy preamble, ii) a wakeup radio (WUR) preamble, and iii) a data portion. The data portion comprises a plurality of time segments, each time segment corresponds to a respective information bit. The data portion is generated to include a respective prefix inserted prior to each time segment corresponding to the respective bit to mitigate intersymbol interference at a receiver caused at least by multipath effects.

Abstract: The present disclosure includes systems and techniques relating to training sequences used in wireless communication systems. In some implementations, a transmission mode of a transmitting device is determined for transmitting a long training field (LTF) sequence for High Efficiency (HE) wireless local area network (WLAN) communication. Based on the transmission mode, candidate training sequences for the LTF sequence are constructed. Each candidate sequence includes a first number of base sequences and a second number of floating sequences, wherein the base sequences reuse an LTF sequence for Very High Throughput (VHT) WLAN communication. The candidate training sequences are constructed by varying values and locations of the floating sequences. A target training sequence is selected that has a desired peak-to-average power ratio (PAPR) value. The target training sequence is assigned to the transmitting device for transmitting the target training sequence in the LTF for the HE WLAN communication.

Abstract: A communication device generates: i) a physical layer (PHY) preamble of a PHY protocol data unit (PPDU), ii) a first portion of a PHY data payload of the PPDU, and iii) a second portion of the PHY data payload. The PHY preamble includes a first training field, and one or more second training fields. The first portion of the PHY data payload and the second portion of the PHY data payload include a plurality of first orthogonal frequency division multiplexing (OFDM) symbols. Each of multiple first OFDM symbols has a first duration. The communication device generates a PHY midamble of the PPDU to be included between the first and second portions of the PHY data payload. The PHY midamble includes one or more third training fields, each including a respective second OFDM symbol having a second duration shorter than the first duration.

Abstract: A first set of orthogonal frequency domain multiplexing (OFDM) symbols for a first portion of a PHY data unit and a second set of OFDM symbols for a second portion of the PHY data unit are generated. OFDM symbols of the first set are generated with a first OFDM tone spacing. At least some OFDM symbols of the second set are generated with a second tone spacing different from the first tone spacing. A value for a length indicator indicative of a duration of the PHY data unit is determined based on the first tone spacing and the second tone spacing. The first portion of the PHY data unit is generated to include (i) the first set of OFDM symbols and (ii) the length indicator set to the determined value. The second portion of the PHY data unit is generated to include the second set of OFDM symbols.

Abstract: A first communication device generates a first portion of a wakeup packet, which corresponds to a legacy physical layer protocol (PHY) preamble corresponding to a communication protocol, and includes a first orthogonal frequency division multiplexing (OFDM) symbol that spans a first bandwidth. The first communication device generates a second OFDM symbol, which spans the first bandwidth. The first communication device generates a second portion of the wakeup packet, which does not conform to the communication protocol and is configured to prompt a wakeup radio at a second communication device to prompt a network interface at the second communication device to transition from a low power state to an active state. The first communication device transmits the wakeup packet. Modulation of the second OFDM symbol according to a modulation scheme signals to third communication devices operating according to the communication protocol that the wakeup packet does not conform to the communication protocol.

Abstract: A physical layer (PHY) data unit is received via an orthogonal frequency division multiplexing (OFDM) communication channel. The PHY data unit includes (i) a first set of one or more short OFDM symbols generated using a normal tone spacing and (ii) a second set of one or more long OFDM symbols generated using a reduced tone spacing, (iii) an OFDM symbol indicator indicative of a number of OFDM symbols in at least one of (a) the first set of OFDM symbols and (b) the second set of OFDM symbols; Based at least in part on the OFDM symbol indicator, (i) a number of short OFDM symbols in the set of one or more short OFDM symbols and (ii) a number of long OFDM symbols in the set of one or more long OFDM symbols are determined.

Abstract: A heat recovery variable-frequency multi-split heat pump system and a control method thereof. The system includes an outdoor unit and at least two indoor units. The system is a three-pipe heating recovery multi-split heat pump system designed on the basis of a four-way reversing valve, and one indoor unit thereof is provided with two electronic expansion valves and two heat exchangers so that any indoor unit in the system can operate independently under three working conditions of refrigeration, heating or heat recovery dehumidification. Under multi-split condition, the system can operate under six working conditions, namely, the full-refrigeration working condition, the full-heating working condition, the common-heat-recovery working condition, the common-heat-recovery-dehumidification working condition, the heat recovery dehumidification-refrigeration-combination working condition and the heat recovery dehumidification-heating-combination working condition.

Abstract: A first communication device receives, from a second communication device via a communication channel, a plurality of training signals. The first communication device determines, based on the plurality of training signals, a plurality of channel matrices corresponding to a plurality of orthogonal frequency division multiplexing (OFDM) tones. The first communication device generates, based on the plurality of channel matrices, feedback information for the plurality of OFDM tones, the feedback information including (i) steering matrix information for the plurality of OFDM tones and (ii) additional phase information corresponding to the plurality of channel matrices for the plurality of OFDM tones, the additional phase information for reducing phase discontinuity across the OFDM tones in steered transmissions that are to be subsequently transmitted from the second communication device to the first communication device.

Abstract: A boundary within a last orthogonal frequency division multiplexing (OFDM) symbol of a PHY data unit is determined. Pre-encoder padding bits are added to a set of information bits to generate a set of padded information bits such that the set of padded information bits, after being encoded, fill one or more OFDM symbols up to the boundary within the last OFDM symbol. The set of padded information bits are encoded to generate a set of coded bits. A PHY preamble is generated to include a subfield that indicates the boundary. The one or more OFDM symbols are generated to include (i) the set of coded information bits in the one or more OFDM symbols up to the boundary to allow a receiving device to stop decoding the one or more OFDM symbols at the boundary, and (ii) post-encoder padding bits in the last OFDM symbol following the boundary.

Abstract: A system including a modulator, a repetition module, and a phase rotation module. The modulator is configured to (i) modulate data using dual sub-carrier modulation, and (ii) generate modulated symbols for transmission on a plurality of subcarriers. The repetition module is configured to repeat the modulated symbols from a first half of the plurality of subcarriers to a second half of the plurality of subcarriers. The phase rotation module is configured to rotate phase of the modulated symbols on selected subcarriers of the second half of the plurality of subcarriers.

Abstract: Aspects of the disclosure provide an apparatus that includes a transceiver circuit and a processing circuit. The transceiver circuit is configured to receive a trigger signal this is transmitted by another apparatus. The trigger signal triggers transmissions by a first group of apparatuses including the apparatus, and defers transmissions by a second group of apparatuses that interfere the transmissions by the first group of apparatuses. The processing circuit is configured to, in response to the trigger signal, generate a frame with a first preamble structure that is different from a second preamble structure that is used by the second group of apparatuses, and provide the generated frame to the transceiver circuit for transmission.

Abstract: A physical layer (PHY) preamble of a PHY data unit is generated, including generating one or more short orthogonal frequency division multiplexing (OFDM) symbols for one or more long training fields of the PHY preamble. Each of the one or more short OFDM symbols corresponds to a frequency domain sequence having a number of tones. Every N-th tone is modulated and tones between modulated tones are zero tones, where N is a positive integer greater than one. A time duration of each short OFDM symbol is 1/N of a time duration of a full inverse discrete Fourier transform (IDFT) of the frequency domain sequence. A data portion of the PHY data unit is generated, including generating one or more long OFDM symbols. A time duration of each long OFDM symbol is greater than a time duration of each of the one or more short OFDM symbols.

Abstract: A first set of orthogonal frequency domain multiplexing (OFDM) symbols for a first portion of a PHY data unit and a second set of OFDM symbols for a second portion of the PHY data unit are generated. OFDM symbols of the first set are generated with a first OFDM tone spacing. At least some OFDM symbols of the second set are generated with a second tone spacing different from the first tone spacing. A value for a length indicator indicative of a duration of the PHY data unit is determined based on the first tone spacing and the second tone spacing. The first portion of the PHY data unit is generated to include (i) the first set of OFDM symbols and (ii) the length indicator set to the determined value. The second portion of the PHY data unit is generated to include the second set of OFDM symbols.