Method and apparatus for a wireless local area network

• US 5,553,076 A
• Filed: 05/02/1994
• Issued: 09/03/1996
• Est. Priority Date: 05/02/1994
• Status: Expired due to Term

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: TCSI Corp. (Rocket Software Incorporated)
• Inventors: Flores, Christopher, Behtash, Saman, Ghanem, Adel
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): TON, DANG T
• Application Number:
  US08/236,588
• Time in Patent Office: 855 Days
• Field of Search: 370/94.1, 370/95.1, 370/95.3, 370/16, 370/50, 370/58.1, 370/58.2, 370/58.3, 370/68, 370/69.1, 370/77, 370/85.7, 370/85.13, 370/94.2, 370/94.3, 370/95.2 , 370/100.1, 370/105.1, 370/110.1, 370/108, 370/48, 370/57, 381/86, 381/57, 381/104, 381/107, 455/238, 455/164.1, 455/192.2, 455/196.1, 455/38.1, 455/23, 455/33.1, 455/33.2, 455/37.1, 455/51.1, 455/56.1, 375/12, 375/106, 375/14, 375/95, 375/94, 375/0, 375/81, 375/93, 375/10.121, 375/230, 375/232, 375/213, 375/354, 375/340, 375/205, 375/200, 375/207, 375/356, 375/359, 375/362 , 375/364, 375/369, 329/304, 329/310, 329/318, 379/58, 379/59, 379/60
• US Class Current: 370/311
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 4/12 Messaging; Mailboxes; Announcements
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A protocol for wireless local area network communication between a base stationary unit and a plurality of wireless terminals is disclosed. The main features of this protocol is based upon channel reservation requests by active wireless terminals. Contention is resolved and authorization is granted with data message signals transmitted by the authorized wireless terminal either immediately for asynchronous service or periodically for a time-based service. The system further provides for the base stationary unit to query the receipt of the data message signal by the wireless terminal authorized to receive the transmission. If no response signal is received, then the base stationary unit would authorize for itself transmission of the data message to relay it, either "over the air" or via wired connection to another base stationary unit in another data cell. The synchronous nature of the method provides for power saving by allowing the receiver and/or transmitter to be powered down during idle and other time slots.

Claims

1. A method for wireless communication between a plurality of wireless terminals and a base station, said method comprising:

transmitting periodically by said base station, at the start of a first period of time, a synchronization signal and a status signal, transmitted over an initial period of time measured from the commencement of said first period of time, wherein said synchronization signal is a clocking signal and wherein said status signal represents command signal controlling communication to or from said base station;

transmitting a request signal by one of said plurality of wireless terminals, in a second period of time after a predetermined period measured from the commencement of said second period of time, said request signal indicating the identity of the one of said plurality of wireless terminals requesting subsequent transmission, the identity of one or more wireless terminals to whom the subsequent transmission is intended, the number of periods of time required for the subsequent transmission, and the frequency of the subsequent transmission;

receiving by said base station said request signal and responding thereto by transmitting at the start of a third period of time, different from said first period of time, a synchronization signal, a busy status signal, and an authorization signal, indicating the identity of the one wireless terminal authorized to transmit, the identity of one or more wireless terminals authorized to receive, a starting period of time, and the number of periods of time;

transmitting by said base station at the start of said starting period of time, a synchronization signal and a first reserve status signal; and

transmitting a data signal by the one wireless terminal immediately after the transmission of said first reserve status signal by said base station.

2. The method of claim 1 wherein said request signal is transmitted in said first period of time.

3. The method of claim 1 wherein said request signal is transmitted in a second period of time different from said first period of time.

4. The method of claim 1 further comprising the steps of:

receiving said synchronization signal by said plurality of wireless terminals to synchronize their clocks after said first period of time.

5. The method of claim 1 further comprising the step of:

receiving said data signal by said base station, transmitted by said wireless terminal authorized; and

storing said data signal received.

6. The method of claim 5 further comprising the step of:

transmitting by said base station at the start of a period of time, after transmission of said data signal by the one wireless terminal, a synchronization signal and a second reserve status signal, said second reserve status signal indicating said base station waiting for a response signal from the wireless terminal authorized to receive the data signal.

7. The method of claim 6 further comprising the step of:

retransmitting said data signal by said base station in the event no response signal is received by said base station.

8. The method of claim 5 further comprising the step of retransmitting by said base station as a broadcast signal to said plurality of wireless terminals authorized to receive said data signal.

9. The method of claim 7 wherein said data signal is retransmitted by said base station as a wired relay signal to a second base station for wireless retransmission by said second base station.

10. The method of claim 9 wherein said data signal is retransmitted by said base station as a wired relay signal and is retransmitted by said second base station to a plurality of wireless terminals authorized to receive said data signal.

11. The method of claim 9 wherein said data signal is retransmitted by said base station as a wired relay station and is retransmitted by said second base station to a wireless terminal authorized to received said data signal.

12. The method of claim 1 wherein said base station transmits a synchronization signal after a plurality of periods of time in the event said base station and said plurality of wireless terminals are idle.

13. A method of operating a wireless terminal for communicating wirelessly with a base unit, said method comprising:

supplying power to said wireless terminal periodically at the commencement of a period of time;

receiving a synchronization signal and a status signal transmitted from said base unit by said wireless terminal after the start of said period of time;

decoding said status signal into one of three possible representations;

maintaining power to the receiver of said wireless terminal for the remainder of said period of time, in the event said status signal is one representation;

maintaining power to the receiver of said wireless terminal only if said terminal is the authorized recipient of the transmission, for the remainder of said period of time, and maintaining power to the transmitter of said wireless terminal only if said terminal is the authorized source of the transmission, for the remainder of said period of time, in the event said status signal is a second representation; and

maintaining power only to the transmitter of said wireless terminal, if said terminal desires to transmit in the event said status signal is a third representation.

14. The method of claim 13 wherein said synchronization signal has a spreading sequence known a priori to the base unit and the wireless terminal.

15. The method of claim 14 wherein said status signal associated with said synchronization signal is derived therefrom.

16. A wireless communication system for communication between a plurality of wireless terminals and a base station, said system comprising:

means for transmitting periodically by said base station, at the start of a first period of time, a synchronization signal and a status signal, transmitted over an initial period of time measured from the commencement of said first period of time, wherein said synchronization signal is a clocking signal and wherein said status signal represents command signal controlling communication to or from said base station;

means for transmitting by one of said plurality of wireless terminals a request signal, in a second period of time after a predetermined period measured from the commencement of said second period of time, said request signal indicating the identity of the one wireless terminal requesting subsequent transmission, the identity of the wireless terminals to whom the subsequent transmission is intended, the number of periods of time required for the subsequent transmission, and the frequency of the subsequent transmission;

means for responding by said base station to the receipt of the request signal by transmitting at the start of a third period of time, different from said first period of time, a synchronization signal, a busy status signal, and an authorization signal, indicating the identity of the wireless terminal authorized to transmit, the identity of one or more wireless terminals authorized to receive, a starting period of time, and the number of periods of time;

means for transmitting by said base station at the start of said starting period of time, a synchronization signal and a first reserve status signal; and

means for transmitting a data signal by the one wireless terminal immediately after the transmission of said first reserve status signal by said base station.

17. The system of claim 16 wherein said request signal is transmitted in said first period of time.

18. The system of claim 16 wherein said request signal is transmitted in said second period of time, different from said first period of time.

19. The system of claim 16 further comprising:

means for receiving said data signal by said base station, transmitted by said wireless terminal authorized; and

means for storing said data signal received by said base station.

20. The system of claim 19 further comprising:

means for transmitting by said base station at the start of a period of time, after transmission of said data signal by the authorized wireless terminal, a synchronization signal and a second reserve status signal, said second reserve status signal indicating said base station waiting for a response signal from the wireless terminal authorized to receive the data signal.

21. The system of claim 20 further comprising:

means for retransmitting said data signal by said base station in the event no response signal is received by said base station.

22. The system of claim 20 further comprising:

means for retransmitting said data signal as a broadcast signal to a plurality of wireless terminals authorized to receive said data signal, in the event no response signal is received by said base station.

23. The system of claim 21 wherein said means for retransmitting retransmits said data signal as a wired relay signal to a second base station for wireless retransmission by said second base station.

24. The system of claim 23 wherein said means for retransmitting retransmits said data signal as a wired relay signal to said second base station for retransmission to a plurality of wireless terminals authorized to receive said data signal.

25. The system of claim 23 wherein said means for retransmitting retransmits said data signal as a wired relay station to said second base station for retransmission to a wireless terminal authorized to received said data signal.

26. A wireless terminal for communicating wirelessly with a base unit, said terminal comprising:

means for supplying power to said wireless terminal periodically at the commencement of a period of time;

means for receiving a synchronization signal and a status signal transmitted from the base unit by said wireless terminal after the start of said period of time;

means for decoding said status signal into one of three possible representations; and

means for maintaining power to the receiver of said wireless terminal for the remainder of said period of time, in the event said status signal is one representation;

and for maintaining power to the receiver of said wireless terminal only if said terminal is the authorized recipient of the transmission, for the remainder of said period of time, and maintaining power to the transmitter of said wireless terminal only if said terminal is the authorized source of the transmission, for the remainder of said period of time, in the event said status signal is a second representation;

and for maintaining power only to the transmitter of said wireless terminal, if said terminal desires to transmit in the event said status signal is a third representation.

27. A method of operating a wireless terminal in wireless communication with a stationary base unit to conserve power usage, said method comprising the steps of:

supplying cordless power to said wireless terminal periodically at the commencement of a period of time;

receiving a synchronization signal and a status signal transmitted from the base unit by said wireless terminal after the start of said period of time;

decoding said status signal into one of three possible representations; and

maintaining cordless power to the receiver of said wireless terminal for the remainder of said period of time, in the event said status signal is one representation;

or

maintaining power to the receiver of said wireless terminal only if said terminal is the authorized recipient of the transmission, for the remainder of said period of time, and maintaining power to the transmitter of said wireless terminal only if said terminal is the authorized source of the transmission, for the remainder of said period of time, in the event said status signal is a second representation;

or

maintaining power only to the transmitter of said wireless terminal, if said terminal desires to transmit in the event said status signal is a third representation.

28. A base station for communicating wirelessly with a plurality of wireless terminals, said base station comprising:

means for transmitting periodically, at the start of a first period of time, a synchronization signal and a status signal, transmitted over an initial period of time measured from the commencement of said first period of time, wherein said synchronization signal is a clocking signal and wherein said status signal represents command signal controlling communication to or from said base station;

means for receiving a request signal transmitted by one of said plurality of wireless terminals in a second period of time, subsequent to said first period of time, said request signal indicating the identity of the one wireless terminal requesting subsequent transmission, the identity of one or more wireless terminals to whom the subsequent transmission is intended, the number of periods of time required for the subsequent transmission, and the frequency of the subsequent transmission;

means for responding to the receipt of the request signal by transmitting at the start of a third period of time, different from said first and second periods of time, a synchronization signal, a busy status signal, and an authorization signal, indicating the identity of the one wireless terminal authorized to transmit, the identity of one or more wireless terminals authorized to receive, a starting period of time, and the number of periods of time; and

means for transmitting at the start of said starting period of time, a synchronization signal and a first reserve status signal, wherein said first reserve status signal is a control signal permitting the one wireless terminal to transmit a data signal immediately after the transmission of said first reserve status signal.

29. The base station of claim 28 wherein said receiving means receives said request signal, in said first period of time after said initial period of time measured from the commencement of said first period of time.

30. The base station of claim 28 wherein said receiving means receives said request signal, in said second period of time, different from said first period of time after said initial period of time measured from the commencement of said second period of time.

31. The base station of claim 28 further comprising:

means for receiving said data signal, transmitted by said wireless terminal authorized; and

means for storing said data signal received.

32. The base station of claim 31 further comprising:

means for transmitting at the start of a period of time, after transmission of said data signal by the authorized wireless terminal, a synchronization signal and a second reserve status signal, said second reserve status signal indicating said base station waiting for a response signal from the wireless terminal authorized to receive the data signal.

33. The base station of claim 32 further comprising:

means for retransmitting said data signal in the event no response signal is received.

34. The base station of claim 31 further comprising:

means for retransmitting said data signal as a broadcast signal to a plurality of wireless terminals authorized to receive said data signal.

35. The base station of claim 33 wherein said means for retransmitting retransmits said data signal as a wired relay signal to a second base station for wireless retransmission by said second base station.

36. The base station of claim 33 wherein said means for retransmitting retransmits said data signal as a wired relay signal to said second base station for retransmission to a plurality of wireless terminals authorized to receive said data signal.

37. The base station of claim 33 wherein said means for retransmitting retransmits said data signal as a wired relay station to said second base station for retransmission to a wireless terminal authorized to received said data signal.

38. A method of operating a base station in wireless communication with a plurality of wireless terminals, said method comprising the steps of:

transmitting periodically, at the start of a first period of time, a synchronization signal and a status signal, transmitted over an initial period of time measured from the commencement of said first period of time, wherein said synchronization signal is a clocking signal and wherein said status signal represents command signal controlling communication to or from said base station;

receiving a request signal transmitted by one of said plurality of wireless terminals in a second period of time, said request signal indicating the identity of the one wireless terminal requesting subsequent transmission, the identity of one or more wireless terminals to whom the subsequent transmission is intended, the number of periods of time required for the subsequent transmission, and the frequency of the subsequent transmission;

responding to the receipt of the request signal by transmitting at the start of a third period of time, different from said first and second periods of time, a synchronization signal, a busy status signal, and an authorization signal, indicating the identity of the one wireless terminal authorized to transmit, the identity of one or more wireless terminals authorized to receive, a starting period of time, and the number of periods of time; and

transmitting at the start of said starting period of time, a synchronization signal and a first reserve status signal, wherein said first reserve status signal is a control signal permitting the one wireless terminal to transmit a data signal immediately after the transmission of said first reserve status signal.

39. The method of claim 38 further comprising the step of:

receiving said data signal, transmitted by said wireless terminal authorized; and

storing said data signal received.

40. The method of claim 39 further comprising:

transmitting at the start of a slot, after transmission of said data signal by the authorized wireless terminal, a synchronization signal and a second reserve status signal, said second reserve status signal indicating said base station waiting for a response signal from the wireless terminal authorized to receive the data signal.

41. The method of claim 40 further comprising:

retransmitting said data signal in the event no response signal is received.

42. The method of claim 41 further comprising:

retransmitting said data signal as a broadcast signal to a plurality of wireless terminals authorized to receive said data signal.

43. The method of claim 42 further wherein said retransmitting step retransmits said data signal as a wired relay signal to a second base station for wireless retransmission by said second base station.

44. The base station of claim 42 wherein said retransmitting step retransmits said data signal as a wired relay signal to said second base station for retransmission to a plurality of wireless terminals authorized to receive said data signal.

45. The method of claim 42 wherein said retransmitting step retransmits said data signal as a wired relay station to said second base station for retransmission to a wireless terminal authorized to received said data signal.