Medium access control protocol for wireless network

• US 5,371,734 A
• Filed: 01/29/1993
• Issued: 12/06/1994
• Est. Priority Date: 01/29/1993
• Status: Expired due to Term

• Current Assignee: Atlas IP, LLC
• Original Assignee: Digital Ocean, Inc.
• Inventors: Fischer, Michael A.
• Primary Examiner(s): Chin, Wellington
• Application Number:
  US08/011,415
• Time in Patent Office: 676 Days
• Field of Search: 370/18, 370/95.1, 370/95.3, 340/825.44, 340/825.47, 455/38.2, 455/38.3, 455/53.1, 455/54.1, 455/54.2, 455/68, 455/69, 455/70
• US Class Current: 370/311
• CPC Class Codes: H04W 4/06 Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• 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 52/0274 by switching on or off the equipment or parts thereof
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A communicator station wirelessly transmits frames to and receives frames from a least one additional communicator in a Group in accordance with a MAC protocol. One of the communicators functions as a hub and the remaining communicators function as remotes. The hub sends control information to the hubs to establish repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames. The intervals allow the hub and the remotes to anticipate transmitting and receiving frames, thereby allowing the remotes to power off their receivers and transmitters to achieve a considerable savings in power consumption without degrading communications. Other improved features include adjusting the intervals and the durations of transmission opportunities in the communication cycle to obtain the beneficial aspects of TDMA and PRMA for LAN-like communication without also incurring most of the undesirable aspects of such MAC techniques. Other control functions such as arbitration determine which communicator is better suited to act as the hub.

Claims

1. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each communication cycle having intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting cycle establishing information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the hub transmitting a frame containing the cycle establishing information which establishes both an outbound portion of the communication cycle when the hub transmits frames to the remotes and an inbound portion of the communication cycle when the remotes transmit frames to the hub, the frame containing the cycle establishing information also establishing the predetermined intervals during the outbound and inbound portions of the communication cycle when each remote is allowed to transmit and receive;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the cycle establishing information transmitted from the hub; and

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the cycle establishing information transmitted from the hub.

2. A communicator as defined in claim 1 wherein the predetermined functions further comprise:

the hub assigning transmission opportunities to the remotes, each transmission opportunity being an interval for a remote to transmit frames to the hub; and

the hub transmitting transmission opportunity allocation information in the frame containing the cycle establishing information transmitted by the hub.

3. A communicator as defined in claim 2 wherein the predetermined functions further comprise:

the hub transmitting the frame containing the cycle establishing information to the remotes to establish a transmission opportunity request interval during the communication cycle when the remotes may transmit transmission opportunity request frames to the hub to request transmission opportunity allocations; and

the remotes transmitting transmission opportunity request frames to the hub during the transmission opportunity request intervals.

4. A communicator as defined in claim 3 wherein the predetermined functions further comprise:

the hub allocating a transmission opportunity to the remote within a predetermined number of subsequent communication cycles after the transmission opportunity request frame is received by the hub; and

the hub transmitting transmission opportunity allocation information during the communication cycle after the hub has received the transmission opportunity request.

5. A communicator as defined in claim 2 wherein the predetermined functions further comprise:

the hub allocating a predetermined amount of time for each transmission opportunity, the predetermined amount of time of the transmission opportunity being for a remote to transmit frames to the hub; and

the hub transmitting the frame containing the cycle establishing information which contains the transmission opportunity allocation information during the communication cycle.

6. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub assigning transmission opportunities to the remotes, each transmission opportunity being an interval for a remote to transmit frames to the hub;

the hub transmitting transmission opportunity allocation information in a frame transmitted by the hub; and

the hub allocating a number of transmission opportunities during at least one communication cycle which is at least one less in number than the number of remotes in the Group.

7. A communicator as defined in claim 6 wherein the predetermined functions further comprise:

the hub changing the transmission opportunity allocations in a subsequent communication cycle compared to a previous communication cycle by allocating a transmission opportunity to a remote which had previously not been allocated a transmission opportunity.

8. A communicator as defined in claim 7 wherein the predetermined functions further comprise:

the hub further revoking a previous transmission opportunity allocation of a remote to provide the transmission opportunity allocation to the remote which had previously not been allocated a transmission opportunity.

9. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub assigning transmission opportunities to the remotes, each transmission opportunity being an interval for a remote to transmit frames to the hub;

the hub transmitting transmission opportunity allocation information in a frame transmitted by the hub;

the hub transmitting information to the remotes to establish a transmission opportunity request interval during the communication cycle when the remotes may transmit transmission opportunity request frames to the hub to request transmission opportunity allocations;

the remotes transmitting transmission opportunity request frames to the hub during the transmission opportunity request intervals; and

the hub transmitting information in a frame which requires a remote having a previously allocated transmission opportunity to relinquish the transmission opportunity.

10. A communicator as defined in claim 9 wherein the predetermined functions further comprise:

the remote relinquishing its previously allocated transmission opportunity by transmitting a frame containing the acknowledgement during its allocated transmission opportunity request interval.

11. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub assigning transmission opportunities to the remotes, each transmission opportunity being an interval for a remote to transmit frames to the hub;

the hub transmitting transmission opportunity allocation information in a frame transmitted by the hub;

the hub monitoring the frames transmitted by each remote during its transmission opportunity; and

the hub revoking a previous transmission opportunity allocation of a remote which has not transmitted more than a predetermined number of frames during a previous number of communication cycles.

12. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub assigning transmission opportunities to the remotes, each transmission opportunity being an interval for a remote to transmit frames to the hub;

the hub transmitting transmission opportunity allocation information in a frame transmitted by the hub;

the hub allocating a predetermined amount of time for a transmission opportunity in each transmission opportunity, the predetermined amount of time of the transmission opportunity being for a remote to transmit frames to the hub;

the hub transmitting a frame containing the transmission opportunity allocation information during the communication cycle;

the hub adjusting the length of at least one transmission opportunity of at least one remote during at least one of a plurality of subsequent communication cycles; and

the hub transmitting a frame containing the information establishing the adjusted length of the transmission opportunity prior to the time of the adjusted transmission opportunity in a communication cycle.

13. A communicator as defined in claim 12 wherein the predetermined functions further comprise:

the hub monitoring the frames transmitted by each remote during its transmission opportunity; and

the hub further adjusting the length of the transmission opportunity relative to the number of frames transmitted by each remote during its transmission opportunity.

14. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub establishing the length of each communication cycle; and

the hub transmitting a frame containing information describing the length of the communication cycle prior to the end of the communication cycle whose length is established.

15. A communicator as defined in claim 14 wherein the predetermined functions further comprise:

the hub adjusting the length of a communication cycle relative to the length of a previous communication cycle.

16. A communicator as defined in claim 15 wherein the predetermined functions further comprise:

the hub continually adjusts the length of the communication cycles.

17. A communicator as defined in claim 15 wherein the predetermined functions further comprise:

the hub allocating transmission opportunities to the remotes, each transmission opportunity being an interval for a remote to transmit frames to the hub; and

the hub adjusting the length of a communication cycle relative to the number of transmission opportunities allocated.

18. A communicator as defined in claim 17 wherein the predetermined functions further comprise:

the hub allocating a predetermined amount of time for a transmission opportunity for a remote to transmit frames to the hub;

the hub monitoring the frames transmitted by each remote during its transmission opportunity; and

the hub further adjusting the length of a communication cycle relative to the number of frames transmitted by each remote during its transmission opportunity.

19. A communicator as defined in claim 17 wherein the predetermined functions further comprise:

the hub further adjusting the length of the communication cycle by a randomly generated factor.

20. A communicator as defined in claim 19 wherein the maximum length of communication cycle with the randomly generated factor is less than two times the maximum length of the communication cycle without the randomly generated factor.

21. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators Of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub transmitting two frames containing information to establish the plurality of predeterminable intervals during each communication cycle, the second frame containing the information to established the plurality of predeterminable intervals occurring before the intervals in which the remotes are allowed to transmit frames to the hub.

22. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, wherein the communicators are adapted to be connected to a resource to obtain data from and to supply data to the resource, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

a first remote transmitting a first frame containing data to the hub during an interval established in a first communication cycle, the first frame containing data obtained by the one remote from the resource connected to the one remote; and

the hub transmitting a second frame to a second remote during an interval established in a second subsequent communication cycle, the second frame containing the data contained in the first frame.

23. A communicator as defined in claim 22 wherein the physical distance between the first and second remotes is greater than the distance which either the first or second remote may reliably transmit frames.

24. A communicator as defined in claim 22 wherein the frames are transmitted by radio frequency signals and are received from radio frequency signals.

25. A communicator as defined in claim 24 wherein each remote further includes a plurality of antennas for receiving the radio signal, and the predetermined functions further comprise:

each remote selecting one among the plurality of antennas with which to receive the radio frequency signals during each communication cycle.

26. A communicator as defined in claim 25 wherein the predetermined functions further comprise:

each remote evaluating the strength of the received radio frequency signals with one antenna before selecting another antenna.

27. A communicator as defined in claim 26 wherein the predetermined functions further comprise:

the hub transmitting information to the remotes in a transmission unit which contains at least one frame, the transmission unit including a preamble; and

each remote evaluating the strength of the received radio frequency signals in the preamble before selecting another antenna prior to the end of the preamble.

28. A communicator as defined in claim 27 wherein the predetermined functions further comprise:

each remote further receiving a portion of the preamble with the other antenna after selecting the other antenna.

29. A communicator as defined in claim 24 wherein the Group is established by those communicators which transmit and receive the radio frequency signals on the same radio frequency channels.

30. A communicator as defined in claim 29 wherein the communicators transmit and receive the radio frequency signals using direct sequence spread spectrum modulation established by a predetermined spreading code, and the Group is established by those communicators which modulate and demodulate the radio frequency signals using the same predetermined spreading code.

31. A communicator as defined in claim 24 wherein the predetermined functions further comprise:

the hub transmitting the information to the remotes in a transmission unit which contains at least one frame, the transmission unit including a preamble; and

each remote synchronizing its receipt of signals transmitted from the hub during the communication cycle from the signal transmitted during the preamble.

32. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub transmitting information to the remotes to establish a first interval in the communication cycle during which a frame containing the information establishing the communication cycle and the plurality of predeterminable intervals is transmitted and a second interval during which the hub is allowed to transmit other frames to the remotes; and

each remote determines whether to power off its receiver during the second interval based on the information transmitted during the first interval.

33. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub transmitting a frame containing information to establish a first interval in the communication cycle during which the information establishing the communication cycle and the plurality of predeterminable intervals is transmitted, and a second interval during which the hub is allowed to transmit broadcast frames to the remotes, and a third interval in the communication cycle during which the hub is allowed to transmit directed frames to the remotes;

each remote powers its transmitter during the second interval; and

each remote determines whether to power off its receiver during the third interval based on the information conveyed during the first interval.

34. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined function comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub transmitting information to the remotes during a first communication cycle to establish the length of the first communication cycle and to establish the time for the beginning of the next subsequent second communication cycle; and

the remotes powering on their receivers at approximately the anticipated beginning of the second communication cycle after having powered their receivers off during the first communication cycle, by using the information transmitted from the hub during the first communication cycle.

35. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub transmitting information to the remotes to establish a predeterminable hub beacon interval during one of a predetermined plurality of sequential communication cycles; and

the hub transmitting a hub beacon frame during the hub beacon interval, the hub beacon frame containing information indicating that the hub is functioning as a hub for the Group and describing predetermined operational characteristics of the hub, the hub beacon frame being transmitted to another second hub of another second Group.

36. A communicator as defined in claim 35 wherein the predetermined functions further comprise:

the second hub receiving the hub beacon frame sent by the first aforesaid hub and in response thereto transmitting a hub beacon reply frame to the first hub during the hub beacon interval of the communication cycle of the first hub, the hub beacon reply frame containing information describing predetermined operational characteristics of the second hub; and

the first hub and the second hub responding to the information in the hub beacon reply frame and the hub beacon frame to adjust their respective transmissions of frames and to adjust the communication cycles established to avoid conflict in transmissions.

37. A communicator as defined in claim 36 wherein the predetermined functions further comprise:

the first and second hubs each adjusting their communication cycles so they do not overlap one another.

38. A communicator as defined in claim 37 wherein the frames are transmitted by radio frequency signals and are received from radio frequency signals, and the predetermined functions further comprise:

the first and second hubs transmitting the hub beacon and the hub beacon reply frames on the same predetermined radio frequency channel which is different than the radio frequency channels which the first and second hubs use for transmitting frames to and receiving frames from their remotes.

39. A communicator as defined in claim 37 wherein the frames are transmitted by radio frequency signals and are received from radio frequency signals, the communicators transmit and receive the radio frequency signals using direct sequence spread spectrum modulation established by a predetermined spreading code, and the predetermined functions further comprise:

the first and second hubs use different spreading codes for transmitting frames to and receiving frames from their remotes than the spreading codes used for transmitting the hub beacon and hub beacon reply frames.

40. A communicator as defined in claim 39 wherein the predetermined functions further comprise:

the first and second hubs transmit and receive the hub beacon frame and the hub beacon reply frame using a predetermined spreading code which is different that the spreading code used by each hub to transmit frames to and receive frames from the remotes of their respective Group.

41. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the hub assigning transmission opportunities to the remotes, each transmission opportunity being an interval for a remote to transmit frames to the hub;

the hub transmitting transmission opportunity allocation information in a frame transmitted by the hub;

the hub transmitting information to the remotes to establish a transmission opportunity request interval during the communication cycle when the remotes are allowed to transmit transmission opportunity request frames to the hub to request transmission opportunity allocations;

the remotes transmitting transmission opportunity request frames to the hub during the transmission opportunity request intervals to request transmission opportunities, the transmission opportunity request frames containing information describing predetermined operational characteristics of the remote transmitting the transmission opportunity request frame;

the hub responding to the information in the transmission opportunity request frame and determining if the remote is better suited to act as the hub based on a comparison of the operational characteristic information of the hub and the remote transmitting the transmission opportunity request frame;

the hub transmitting a hub handoff frame to the remote transmitting the transmission opportunity request frame if the hub has determined that the remote is better suited to act as the hub;

the remote responding to the hub handoff frame by transmitting a handoff acknowledgement frame and commencing to act as the hub after transmitting the handoff acknowledgment frame; and

the hub receiving the hub acknowledgement frame commencing to function as a remote after receiving the hub acknowledgement frame.

42. A communicator as defined in claim 41 wherein the communicators are adapted to be connected to a resource to obtain data from and to supply data to the resource, wherein the at least some of the communicators are battery powered, and wherein the predetermined functions further comprise:

the hub determining if the remote is better suited to act as the hub by evaluating predetermined criteria describing operating characteristics obtained from the information of the transmission opportunity request frame and obtained from the hub, the operational characteristics including whether the hub or the remote is battery powered; and

the hub determining that the remote is better suited to act as the hub if the remote is not battery powered and the hub is battery powered.

43. A communicator as defined in claim 42 wherein the operating characteristics also include whether the hub or the remote is connected to a resource functioning as a server, and wherein the predetermined functions further comprise:

the hub determining that the remote is better suited to act as the hub if the remote is not connected to a resource functioning as a server and the hub is connected to a resource functioning as a server, after the hub has determined that both the hub and the remote are both connected to or both not connected to battery power.

44. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the communicators transmitting a transfer unit from one communicator to another which contains a plurality of frames;

the remotes transmitting a transfer unit having a header having at least one field containing information describing at least one frame of a previous transmission unit which was not successfully received by the hub; and

the hub responding to the field information describing the frame which was successfully received by transmitting in another subsequent transfer unit those remaining frames of the previous transfer unit which were not successfully received.

45. A communicator as defined in claim 44 wherein the frame has two fields containing information describing at least one frame of a previous transmission unit which was not successfully received, one field containing information describing the ending frame number of the last successfully received frame of the transfer unit, and the other field containing information describing a single frame in the plurality of frames in the transfer unit which was not successfully received.

46. A communicator for wirelessly transmitting frames to and receiving frames from a least one additional communicator in accordance with a predetermined medium access control protocol, the communicators which transmit and receive the frames constituting a Group, each communicator including a transmitter and a receiver for transmitting and receiving the frames respectively, the medium access control protocol controlling each communicator of the Group to effect predetermined functions comprising:

designating one of the communicators of the Group as a hub and the remaining the communicators of the Group as remotes;

the hub establishing repeating communication cycles, each of which has intervals during which the hub and the remotes transmit and receive frames;

the hub transmitting information to the remotes to establish the communication cycle and a plurality of predeterminable intervals during each communication cycle, the intervals being ones when the hub is allowed to transmit frames to the remotes, when the remotes are allowed to transmit frames to the hub, and when each remote is expected to receive a frame from the hub;

the remotes powering off their transmitters during times other than those intervals when the remote is allowed to transmit frames to the hub, by using the information transmitted from the hub;

the remotes powering off their receivers during times other than those intervals when the remote is expected to receive a frame from the hub, by using the information transmitted from the hub;

the remotes transmitting frames to the hub during the communication cycle which contain predetermined operational characteristic information of the remote transmitting the frame;

the hub responding to the operational characteristic information in the frame transmitted from each remote and determining if the remote is better suited to act as the hub based on a comparison of the operational characteristic information of the hub and the remote transmitting the frame;

the communicator functioning as the hub transferring the hub functionality to the remote having operational characteristics better suited to act as the hub; and

the remote receiving the hub functionality thereafter becoming the hub for the Group and the communicator previously functioning as the hub commencing to function as a remote.

47. A communicator as defined in claim 46 wherein the predetermined functions further comprise:

the hub transmitting information to the remotes to establish a transmission opportunity request interval during the communication cycle when the remotes are allowed to transmit transmission opportunity request frames to the hub to request transmission opportunity allocations;

the remotes transmitting transmission opportunity request frames to the hub during the transmission opportunity request intervals to request transmission opportunities, the transmission opportunity request frames containing information describing the predetermined operational characteristics of the remote transmitting the transmission opportunity request frame;

the hub transmitting a hub handoff frame to the remote transmitting the transmission opportunity request frame if the hub has determined that the remote is better suited to act as the hub;

the remote responding to the hub handoff frame by transmitting a handoff acknowledgement frame and commencing to act as the hub after transmitting the handoff acknowledgment frame; and

the hub receiving the hub acknowledgement frame commencing to function as a remote after receiving the hub acknowledgement frame.