Patents by Inventor Jianhan Liu

Jianhan Liu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9717022
    Abstract: A method of reducing the usable channel bandwidth and increasing the channel bandwidth at run time is provided. The method allows a receiving wireless communications device to inform its corresponding transmitting communications device to either increase, reduce, or maintain the number of usable narrow band channels for the succeeding frame exchange. In a wireless communications channel, channel reduction is accomplished by using a usable channel indicator in a response frame responding to the preceding receiving frame. The usable channel indicator is the means for the receiving communications device to inform the transmitting communications device the preferred narrow band channels that it deems having good channel characteristics.
    Type: Grant
    Filed: December 12, 2013
    Date of Patent: July 25, 2017
    Assignee: MEDIATEK SINGAPORE PTE. LTD.
    Inventors: Chao-Chun Wang, Chih-Shi Yee, Jianhan Liu
  • Publication number: 20170180177
    Abstract: A method of interleaver design for dual carrier modulation (DCM) is proposed in a wireless network. For HE PPDU transmission with DCM, information bits are first encoded by a BCC encoder. The BCC encoded bit streams are then interleaved by a BCC interleaver. More specifically, the BCC interleaved bits are repeated on two halves of a given resource unit (RU). The BCC interleaver parameters are defined based on half of the total number of the data tones of the RU if DCM is applied. The BCC interleaved bits are then modulated and mapped to two halves of the RU by a DCM constellation mapper.
    Type: Application
    Filed: December 16, 2016
    Publication date: June 22, 2017
    Inventors: Tianyu Wu, Jianhan Liu, Gary A. Anwyl, Thomas Edward PARE, JR.
  • Publication number: 20170171796
    Abstract: A method of very high throughput (VHT) operation information subfields design for IEEE 802.11 WLAN is proposed. The VHT operation information subfields comprise a channel width, a channel center frequency segment 0 (CCFS0), and a channel center frequency segment 1 (CCFS1). Multiple definitions of the VHT operation information subfields have been adopted by different access points (AP)s and wireless stations (STAs). In accordance with one novel aspect, upon receiving the VHT operation information element broadcasted by an AP, an STA will first check the channel width indicated by the AP. The STA then follows different definitions under different channel widths. Under such method, the STA can support up to 160 MHz operation mode with APs following different definitions and operating up to 160 MHz mode.
    Type: Application
    Filed: December 8, 2016
    Publication date: June 15, 2017
    Inventors: TIANYU WU, CHAO-CHUN WANG, CHIEN-FANG HSU, JAMES JUNE-MING WANG, JIANHAN LIU, THOMAS EDWARD PARE, JR.
  • Patent number: 9673956
    Abstract: A spatial reuse prioritized channel access scheme is proposed to enhance the average throughput per station in a wireless network by optimizing spatial reuse. Spatial reuse capability (SRC) is defined as a monotonically decreasing function of co-channel interference signal strength from OBSSs. Higher spatial reuse capability can be transformed into higher data rate or less usage of airtime by using higher MCS or less interferences to OBSSs by reducing TX power. By allowing the stations that have larger spatial reuse capability to have higher probability to win channel access contention, the overall network throughput is enhanced.
    Type: Grant
    Filed: August 28, 2015
    Date of Patent: June 6, 2017
    Assignee: MEDIATEK INC.
    Inventors: Jianhan Liu, Tianyu Wu, Rongsheng Huang, James June-Ming Wang
  • Publication number: 20170134207
    Abstract: Signaling and feedback schemes of channel variation information from WLAN receiver are proposed. WLAN receiver performs channel tracking and obtains channel variation information. The signaling and feedback of channel variation information can help WLAN transmitter to decide when to apply travelling pilots or mid-amble in the transmission. Furthermore, the channel variation information can assist WLAN transmitter for scheduling the next transmission properly and thereby enhancing the system performance of WLAN.
    Type: Application
    Filed: November 3, 2016
    Publication date: May 11, 2017
    Inventors: Jianhan Liu, Chih-Kai Chen, Tianyu Wu, Thomas Edward PARE, JR.
  • Publication number: 20170135148
    Abstract: A communication method that operates by determining a first set of physical parameters of a first channel by a coordinator in a wireless communication system; establishing communication with a first set of devices over the first channel; determining a protection period in accordance with a pre-determined rule; broadcasting a channel-adjustment message, wherein the channel-adjustment message comprises a set of instructions for indicating how to adjust from the first channel to a second channel, and the set of instructions comprise channel bandwidth information for indicating how to adjust to a bandwidth of the second channel and central frequency information for indicating how to adjust to a central frequency of the second channel; and communicating with a second set of devices over the second channel during the protection period.
    Type: Application
    Filed: January 19, 2017
    Publication date: May 11, 2017
    Inventors: Chao-Chun WANG, Jianhan LIU, Chih-Shi YEE, Huanchun YE, James June-Ming WANG
  • Publication number: 20170104553
    Abstract: A new lower density parity check (LDPC) tone mapper is proposed when DCM is applied for a given resource unit (RU) when LDPC is used as the channel control coding. For HE PPDU transmission with DCM, LDPC encoded streams are first modulated by a DCM constellation mapper. The modulated symbols of the lower half of the frequency segment and the modulated symbols of the upper half of the frequency segment are modulated using the same LDPC encoded bits using DCM mapping. The modulated symbols of the lower half of the frequency segment are mapped to lower half of the data subcarriers using DCM LDPC tone mapper. The modulated symbols of the upper half of the frequency segment are mapped to upper half of the data subcarriers using the same DCM LDPC tone mapper. Maximum frequency diversity for DCM can be achieved.
    Type: Application
    Filed: October 11, 2016
    Publication date: April 13, 2017
    Inventors: Jianhan Liu, Shengquan Hu, Tianyu Wu, Thomas Edward PARE, JR.
  • Publication number: 20170099089
    Abstract: A method of transmitting and receiving a HE PPDU and perform channel estimation enhancement is proposed. The HE PPDU comprises legacy preamble, HE-STF, HE-LTF, and data. A beam-change indication indicates if the pre-multiplied beamforming Q-matrix is changed from legacy preamble to H-SFT, HE-LTF, and data portion. A value of 1 indicates that Q matrix is changed. A value of 0 indicates that Q matrix is unchanged and receiver should be safe to combine L-LTF and HE-LTF. The beam-change indication can be used to significantly enhance channel estimation at receiver. When there is no beam-change, receiver does not change operation during HE-STF and HE-LTF such that the channel estimations can rely on the combination of L-LTFs, L-SIG, RL-SIG, HE-SIGAs and HE-LTF.
    Type: Application
    Filed: September 30, 2016
    Publication date: April 6, 2017
    Inventors: Jianhan Liu, Shuling Feng, Thomas Edward Pare, JR., YungPing Hsu
  • Publication number: 20170093546
    Abstract: Methods and apparatus are provided for structured resource allocation signaling. In one novel aspect, an 8-bit RU allocation filed is allocated in the HE-SIG-B common field for each 20 MHz. The structured resource signaling supports more than four MU-MIMO users. In one embodiment, the STA decodes the 8-bit RU allocation signal following a structured resource unit (RU) allocation rule, and determines the RU. In one embodiment, the STA decodes the first two bits of the 8-bit RU allocation signal to determine a first category of the RU allocation. The categories of the RU allocation includes a large RU size category indicating larger than or equal to 20 MHz RUs exist, a two 106-tone category indicating two 106-tone RUs exist, and a no-large-RU category indicating only smaller-than-242-tone RUs exist. The STA further decodes based on the category. A lookup table (LUT) for RU allocation is built and decoded based on a structured signaling rule.
    Type: Application
    Filed: September 28, 2016
    Publication date: March 30, 2017
    Inventors: Tianyu Wu, Jianhan Liu, Shengquan Hu, Thomas Edward PARE, JR.
  • Publication number: 20170070962
    Abstract: A method of spatial reuse with opportunistic transmit power control (TPC) and clear channel assessment (CCA) is proposed. In the opportunistic TPC and CCA, a spatial reuse station (SR-STA) gains enough knowledge in certain situation for more aggressive spatial reuse such that its transmit power may be adjusted to meet the spatial reuse conditions based on the received OBSS PPDU and the corresponding spatial reuse parameter (SRP). Both Type 1 SRP and Type 2 SRP are defined. In one example, the Type 1 or Type 2 SRP is a 5-bit parameter carried in the HE-SIG-A field of the OBSS PPDU, which can be a trigger frame, a response frame, a request-to-send (RTS)/clear-to-send (CTS) frame, and a data frame.
    Type: Application
    Filed: September 6, 2016
    Publication date: March 9, 2017
    Inventors: James June-Ming Wang, Jianhan Liu, Chao-Chun Wang, YungPing Hsu
  • Publication number: 20170070893
    Abstract: A method of direction finding (DF) positioning in a wireless location area network (WLAN) is proposed. A multiple antenna IEEE 802.11 transmitting device can transmit signal preamble containing multiple Long Training Field (LTF) symbols in a radio frame from multiple antennas simultaneously, which allows a receiving device to resolve multiple DF sounding signals transmitted from the multiple antennas. As a result, angle of departure (AoD) of the transmitting device can be estimated by using the multiple resolved DF sounding signals from each antenna for DF positioning purpose.
    Type: Application
    Filed: February 24, 2015
    Publication date: March 9, 2017
    Inventors: James June-Ming Wang, Jianhan Liu, Thomas Edward Pare Jr., Tianyu Wu, Gabor Bajko, Yung-Ping Hsu
  • Publication number: 20170070998
    Abstract: Methods and apparatus are provided for HE-SIG-B common field formats and indications. In one novel aspect, a fixed format is used for HE-SIG-B common field indicating resource allocations (RA). In one embodiment, look-up tables (LUT) are configured for the resource allocation and indicated in the HE-SIG-B common field. In one embodiment, one or more RA LUTs are used based on the operation bandwidth. The RA LUTs are placed in an order of channel indexes from lower channel to upper channel signaled in each corresponding RA LUT. In another novel aspect, MU-MIMO is used for operation bandwidth of 160 MHz and a compression indicator is set in the HE-SIG-A field indicating a saving of all RA LUTS in the HE-SIG-B common field. In yet another novel aspect, a one-bit middle-tone indicator is included in the HE-SIG-B common field indicating whether the one or more middle 26 tone is used.
    Type: Application
    Filed: September 7, 2016
    Publication date: March 9, 2017
    Inventors: Tianyu Wu, Shengquan Hu, Jianhan Liu, Thomas Edward PARE, JR.
  • Publication number: 20170063512
    Abstract: A method of sub-channel feedback in OFDMA systems is provided. A wireless receiving device (STA) receives a radio signal from a transmitting device (AP) over a wide channel in an OFDMA system. The radio signal is transmitted over multiple sub-channels of the wide channel. The STA estimates channel quality information based on the received radio signal for each sub-channel. The STA then sends feedback information to the transmitting device. The feedback information comprises the estimated channel quality information for a selected subset of sub-channels from the wide channel based on a predefined rule. In one embodiment, the feedback information is embedded within an ACK/BA frame or is carried in a frame immediately subsequent to the ACK/BA frame.
    Type: Application
    Filed: March 4, 2015
    Publication date: March 2, 2017
    Inventors: Tianyu Wu, Jianhan Liu, KIRAN ULN, Thomas Edward Pare, JR.
  • Patent number: 9572192
    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.
    Type: Grant
    Filed: October 18, 2011
    Date of Patent: February 14, 2017
    Assignee: MEDIATEK SINGAPORE PTE. LTD.
    Inventors: Chao-Chun Wang, Jianhan Liu, Chih-Shi Yee, Huanchun Ye, James June-Ming Wang
  • Publication number: 20160374087
    Abstract: A unified channel contention scheme is proposed such that spatial reuse can be enabled by a wireless station (STA) when a basic service set (BSS) color of a received signal cannot be resolved. If the detected frame is an intra-BSS frame, then the STA should not contend the channel for the PPDU duration. If the detected frame is an inter-BSS frame, then the STA uses OBSS Packet Detection (OBSS-PD) level as the CCA level for channel contention. Furthermore, when BSS color cannot be resolved, channel contention schemes for WiFi signal and non-WiFi signal are differentiated. If the received signal is detected as WiFi signal, then the STA uses WiFi-SIG Detection (WD) level as the CCA level for channel contention. If the received signal is detected as non-WiFi signal, then the STA uses Non-WiFi-SIG Detection (NWD) level as the CCA level for channel contention.
    Type: Application
    Filed: June 13, 2016
    Publication date: December 22, 2016
    Inventors: Jianhan Liu, RongSheng Huang, Li Ma, Chao-Chun Wang
  • Publication number: 20160366548
    Abstract: A method of combined direction finding (DF) and fine timing measurement (FTM) positioning in a wireless location area network (WLAN) is proposed. A multiple antenna IEEE 802.11 transmitting device (AP) can transmit signal preamble containing multiple Long Training Field (LTF) symbols in a radio frame from multiple antennas, which allows a receiving device (STA) to resolve multiple DF sounding signals transmitted from the multiple antennas and thereby estimating angle of departure (AoD). On the other hand, the AP can estimate angle of arrival (AoA) from radio signals transmitted from the STA. When the radial resolution error of AoD or AoA positioning increases, DF positioning and fine-timing measurement (FTM) ranging can be jointly applied to reduce the radial resolution error and extends the AoD/AoA service area with positing accuracy.
    Type: Application
    Filed: February 24, 2015
    Publication date: December 15, 2016
    Inventors: James June-Ming Wang, Jianhan Liu, Thomas Edward Pare, JR., Tianyu Wu, Gabor Bajko, Yung-Ping Hsu
  • Publication number: 20160353275
    Abstract: A method for identifying source BSS in WLAN is proposed. A high efficiency (HE) access point (AP) sends a packet containing a basic service set (BSS) color to a HE station. The HE AP also sends a packet containing an assigned association identification (AID) to a very high throughput (VHT) station. The assigned AID comprises at least part of the BSS color information. The VHT station therefore sends a packet containing the at least part of the BSS color information such that any AP or station that receives the packet can determine the BSS the VHT station is in.
    Type: Application
    Filed: February 10, 2015
    Publication date: December 1, 2016
    Inventors: Jianhan Liu, Tianyu Wu, Thomas Edward Pare Jr.
  • Publication number: 20160352552
    Abstract: Modulation schemes that use dual sub-carrier to reliably transmit physical layer related signaling information and/or data in high efficiency wireless local area network (HE WLAN) are proposed. The proposed schemes can be implemented with low complexity and provide better performance than existing modulation schemes used in WLAN that are based on IEEE 802.11/a/b/g/n/ac standards. The proposed schemes enhance the reliability of transmissions, especially under narrow band interferences. In accordance with a novel aspect, dual subcarrier modulation (DCM) is introduced in HE WLAN. DCM can introduce frequency diversity into OFDM systems by transmitting the same information on two subcarriers separated in frequency. A DCM indication scheme is used such that both encoding and decoding of DCM is really simple.
    Type: Application
    Filed: May 25, 2016
    Publication date: December 1, 2016
    Inventors: Jianhan Liu, Tianyu Wu, Thomas Edward PARE, JR., YungPing Hsu
  • Publication number: 20160329940
    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.
    Type: Application
    Filed: July 15, 2016
    Publication date: November 10, 2016
    Inventors: James June-Ming WANG, Jianhan LIU, Vishakan PONNAMPALAM, Chao-Chun WANG, Huanchun YE
  • Publication number: 20160301445
    Abstract: The present invention provides a method and an electronic apparatus for transmitting a packet with changeable spreading factor. The method comprises: utilizing a spreading circuit to select a spreading factor from a plurality of spreading factors according to a transmitting condition to adjust a spreading for the packet; and transmitting the packet. The electronic apparatus comprises: a spreading circuit and a transmitting circuit. The spreading circuit is utilized for selecting a spreading factor from a plurality of spreading factors according to a transmitting condition to adjust the spreading for the packet. The transmitting circuit is coupled to the spreading circuit, and utilized for transmitting the packet.
    Type: Application
    Filed: March 28, 2016
    Publication date: October 13, 2016
    Inventors: Jianhan Liu, Chien-Fang Hsu