Heterogeneous MAC protocol for multiple base stations in wireless networks

• US 8,059,623 B2
• Filed: 04/06/2009
• Issued: 11/15/2011
• Est. Priority Date: 04/11/2008
• Status: Active Grant

• Current Assignee: Vislink Technologies, Inc.
• Original Assignee: xG Technology, Inc.
• Inventors: Shukla, Amit, Vu, Hai, Gandham, Shashidhar R.
• Primary Examiner(s): Ismail; Shawki S
• Assistant Examiner(s): Hammond; Crystal L
• Application Number:
  US12/384,546
• Publication Number:
  US 20090257415A1
• Time in Patent Office: 953 Days
• Field of Search: 370310-353, 455/500, 455/501, 455/524, 455/562.1
• US Class Current: 370/338
• CPC Class Codes: H04W 74/02 Hybrid access
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

This disclosure describes a new interference avoidance Medium Access Control (MAC) protocol that combines contention-free and contention-based MAC protocols into a heterogeneous MAC protocol used for forwarding VoIP traffic in VoIP systems on wireless networks using multiple base stations which addresses additional interference elimination and the need to transport high bit-rate data to multiple users over wired and wireless means.

Claims

1. A medium access control protocol device for interference avoidance in identified interference areas that combines contention-free and contention-based medium access control protocols into a heterogeneous medium access control protocol used for forwarding Internet Protocol packets containing voice traffic, signaling traffic, and application data traffic between multiple base stations and mobile nodes in a voice over internet protocol system on a wireless network having multiple interfering base stations comprising:

two or more base stations in electrical communication with the Internet;

said two or more base stations each having 360 degree antennas with each of said antennas divided into two or more sectors wherein each of said two or more sectors are separately identified and with each of the said two or more base stations having similarly facing sectors having those similarly facing sectors being similarly identified;

wherein when said similarly identified sectors are on adjacent base stations said similarly identified sectors are further sub-identified as prime sub-identified or non-prime sub-identified such that no two prime sub-identified sectors are adjacent and no two non-prime sub-identified sectors are adjacent;

said two or more base stations having clocks for synchronization;

one or more mobile nodes in wireless electrical communication with said two or more base stations;

said two or more base stations and said one or more mobile nodes each having a medium access control protocol;

said medium access control protocol having hyper-frames each having a time duration equal to a packetization interval dynamically determined by the duration of the voice traffic in said Internet Protocol packets;

said hyper-frames comprised of two or more super-frames of equal durations of time wherein the number of said super-frames is determined by the number of interfering base stations and wherein each of said two or more super-frames is time coordinated with each of said two or more similarly identified sectors of said interfering base stations;

each of said two or more super-frames made up of an initial time for contention-free timeslot based access voice traffic and a remainder time for contention-based access signaling traffic and application data traffic;

said two or more base stations first dynamically determining a time duration of each of said two or more super-frames and said initial time for contention-free timeslot based access based on the number of said two or more super-frames and the packetization;

said initial time for contention-free timeslot based access then being divided into a control data timeslot, a downlink timeslot, and an uplink timeslot wherein the control data timeslot contains information regarding a current super-frame of said two or more super-frames and said one or more mobile nodes are all capable of receiving said information during said control data timeslot in each of said two or more super-frames;

said contention-based access then containing control messages transmitted between each of said two or more base stations and said one or more mobile nodes when said one or more mobile nodes join or leave the wireless network or initiate a voice session;

said one or more mobile nodes then using carrier sense multiple access with collision avoidance with binary exponential back off contention-based access;

wherein said control messages are then assigned a highest priority, said signaling traffic are assigned a lower priority, and said data application messages are assigned a lowest priority;

wherein said control data timeslot is then used to transmit messages between each of said two or more base stations and to synchronize said clocks such that all of said similarly identified sectors are scheduled to transmit or receive at the same time;

wherein any two adjacent base stations having similarly identified sectors then using the same uplink timeslot and downlink timeslot time duration; and

, wherein said super-frame is further divided into prime super-frame and non-prime super-frame and said prime sub-identified sectors of adjacent base stations then operating only during said prime super-frame and said prime sub-identified sectors and non-prime sub-identified sectors of adjacent base stations operate during said non-prime super-frame and said one or more mobile nodes located in identified interference areas detected by said one or more mobile nodes always handing off to said non-prime sub-identified sectors.

2. The medium access control protocol device of claim 1 wherein a limit is set on the number of said Internet Protocol packets for each of said one or more mobile nodes such that if the number of said Internet Protocol packets to be sent by one of said two or more base stations to said one or more mobile nodes exceeds the limit the base station will drop one or more of said Internet Protocol packets.

3. The medium access control protocol device of claim 1 wherein said Internet Protocol packets contain a time stamp and are sorted by each of said two or more base stations according to said time stamp and then sent to said one or more mobile nodes in accordance with said time stamp such that said Internet Protocol packet with the earliest time stamp is sent before later time stamped Internet Protocol packets.