Patents by Inventor Yanfeng Zhang

Yanfeng Zhang 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).

  • Publication number: 20080064404
    Abstract: Methods and device for user terminal based fast handoff are provided. User terminal builds a neighbor group list in which possible neighbor access points (APs) are divided into one or more groups. When a handoff needs to be prepared, the user terminal performs intermittently multiple pre-break probing subphases according to the neighbor group list while not breaking connection with a current serving AP. In each PBP subphase, signal qualities of neighbor APs in one group are probed in a manner of active probing. The user terminal selectively performs handoff according to the probed signal qualities of the neighbor APs. The user terminal may build the neighbor group list based on information of neighbor APs derived through overlapped channel scanning or information of neighbor APs received from the serving AP. The neighbor APs belonging to the same group work on the same channel and in each PBP subphase, a group of neighbor APs may be probed by using unicast probe request.
    Type: Application
    Filed: September 5, 2007
    Publication date: March 13, 2008
    Applicant: NEC (China) Co., Ltd.
    Inventors: Yanfeng Zhang, Yongqiang Liu, Yong Xia
  • Publication number: 20080062933
    Abstract: Methods, devices and system for access point facilitated fast handoff are provided. Each access point (AP) in a wireless local area network is provided with a primary interface and a secondary interface wherein the primary interface performs normal communication with user terminals and broadcasts standard beacon frames on its working channel, and the secondary interface broadcasts extended beacon frames on working channels of neighbor APs sequentially. The extended beacon frame includes at least information of BSSID, SSID, working channel and the like of the primary interface of the corresponding AP. The user terminal may receive the standard beacons from the serving AP it is communicating with and the extended beacons from the neighbor APs, and according to the two kinds of beacons, the terminal may calculate the signal quality with the primary interface of the serving AP and the signal qualities with the neighbor APs at the current position.
    Type: Application
    Filed: September 6, 2007
    Publication date: March 13, 2008
    Applicant: NEC (CHINA) CO., LTD.
    Inventors: Yongqiang Liu, Yanfeng Zhang, Yong Xia