Multiple access radio system

• US 5,577,024 A
• Filed: 10/16/1995
• Issued: 11/19/1996
• Est. Priority Date: 07/08/1993
• Status: Expired due to Term

• Current Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Jokinen, Harri, Malkamaki, Esa
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US08/543,690
• Time in Patent Office: 400 Days
• Field of Search: 370/18, 370/50, 370/85.2, 370/95.1, 370/95.3, 375/200, 375/203, 375/205
• US Class Current: 370/335
• CPC Class Codes: H04L 1/16 in which the return channel carries supervisory signals, e.g. repetition request signals
• CPC Class Codes: H04L 1/1692 Physical properties of the supervisory signal, e.g. acknowledgement by energy bursts
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 2001/125 Arrangements for preventing errors in the return channel
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 5/06 the signals being represented by different frequencies combined with time-division multiplexing H04L5/26
• CPC Class Codes: H04L 5/26 combined with the use of different frequencies
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource

Abstract

The invention relates to a communication method for a digital cellular mobile telephone system and a digital cellular mobile telephone system comprising several base stations and mobiles utilizing time division multiple access. In the system communication is carried out on a predetermined frequency band in a predetermined number of time slots having a predetermined length. In the communication between the mobiles and the base station within the TDMA time slot with the predetermined length, the transmissions to communicate information comprising a few bits or several bits from the mobiles communicating with the same base station at least within the same time slot are mutually substantially orthogonal. Preferably, in order to communicate information, preferably information of the on-off type, such as acknowledgments and channel allocation requests, the mobiles communicating with the same base station use substantially orthogonal transmissions at least to the same base station in the same time slot. Preferably each mobile transmits within the TDMA burst of said TDMA time slot of the predetermined length as a part of the burst a predetermined bit sequence corresponding to the transmitted information bit combination, whereby the predetermined frequency band is unchanged. The bit sequences transmitted by different mobiles to the same base station are mutually substantially orthogonal. By using such substantially orthogonal transmissions it is possible to avoid collisions between the communications of information comprising a few or several bits, typically 1 to 10 bits, such as acknowledgments and channel allocation requests, which typically occur in a time division multiple access system.

Claims

1. A radio communications system, comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot, a

and wherein said at least one second slot is comprised of a plurality of mutually orthogonal sub-slots.

2. A radio communications system comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot,

and wherein said messages are acknowledgement messages generated by a user transceiver and transmitted by said transmitting means in response to receiving communications traffic information from said radio channel.

3. A radio communications system as set forth in claim 2, wherein said messages further comprise channel allocation request messages generated by a user transceiver and transmitted by said transmitting means in response to the user transceiver seeking to establish communications with said central transceiver.

4. A radio communications system as set forth in claim 2, wherein m is equal to 1≦

m≦

10.

5. A radio communications system comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot,

and wherein said messages are acknowledgement messages generated by a user transceiver and transmitted by said transmitting means in response to an error that occurs while receiving communications traffic information from said radio channel.

6. A radio communications system comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot,

wherein said messages are acknowledgement messages generated by a user transceiver and transmitted by said transmitting means in response to receiving communications traffic information from said radio channel,

and wherein said at least one second slot is temporally divided into a plurality of sub-slots.

7. A radio communications system as set forth in claim 6, wherein said at least one second slot is not pre-assigned to any of said plurality of user transceivers.

8. A radio communications system as set forth in claim 6, wherein said central transceiver is a base station of a digital cellular communications system, and wherein at least some of said plurality of user transceivers are mobile radiotelephones.

9. A radio communications system comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot,

and wherein said at least one second slot is frequency divided into a plurality of sub-slots.

10. A radio communications system comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot,

and wherein said at least one second slot is code divided into a plurality of sub-slots.

11. A radio communications system comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot,

and wherein said at least one second slot is divided into a plurality of sub-slots by a bit sequence that is assigned to individual ones of user transceivers to transmit during said at least one second slot, each of said assigned bit sequences being one of mutually orthogonal and substantially orthogonal to other assigned bit sequences.

12. A radio communications system comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot,

and wherein said at least one second slot is divided into a plurality of sub-slots by a spreading code that is assigned to individual ones of user transceivers to transmit during said at least one second slot, each of said assigned spreading codes being one of mutually orthogonal and substantially orthogonal to other assigned spreading codes.

13. A radio communications system comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot, and

wherein said transmitting means of each of said user transceivers transmits a radio signal with a first bandwidth during an assigned one of said first time slots, and transmits a radio signal with a second bandwidth during said at least one second slot, and wherein said second bandwidth is narrower than said first bandwidth.

14. A radio communications system comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot,

and wherein said central transceiver is comprised of a receiver;

an equalizer means having input coupled to an output of said receiver for equalizing a transmission received from a user transceiver during one of said plurality of first time slots; and

a plurality of correlator means individual ones of which have an input coupled said output of said receiver for simultaneously detecting a plurality of messages received from a plurality of user transceivers during said at least one second time slot.

15. A radio communications system, comprising:

at least one base station comprising means for transmitting information over a first radio channel and for receiving information over a second radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the second radio channel and for receiving information over the first radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein at least said second radio channel is a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the base station from said transmitting means of a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said frame is comprised at least one second slot that is not pre-assigned to any of said plurality of user transceivers;

wherein said transmitting means of said plurality of user transceivers transmit a channel allocation request message to said base station during said at least one second slot, the transmitted channel allocation request message comprising up to m bits of data, where m<

n;

wherein said transmitting means of multiple ones of said user transceivers transmit a channel allocation request message during said at least one second slot; and

wherein said transmitting means of one of said user transceivers transmits over the second radio channel, during a second slot, an acknowledgement message to the central transceiver in response to one of said user transceiver receiving communications traffic information from the first radio channel and said user transceiver detecting an error that occurs while receiving communications traffic information from the first radio channel.

16. A radio communications system comprising:

at least one base station comprising means for transmitting information over a first radio channel and for receiving information over a second radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the second radio channel and for receiving information over the first radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein at least said second radio channel is a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the base station from said transmitting means of a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said frame is comprised at least one second slot that is not pre-assigned to any of said plurality of user transceivers;

wherein said transmitting means of said plurality of user transceivers transmit a channel allocation request message to said base station during said at least one second slot, the transmitted channel allocation request message comprising up to m bits of data, where m<

n, said transmitting means of said plurality of user transceivers also transmitting acknowledgement messages during said at least one second slot in response to receiving communications traffic information from said first radio channel;

and wherein said transmitting means of multiple ones of said user transceivers transmit a channel allocation request message during said at least one second slot,

wherein said at least one second slot is temporally divided into a plurality of sub-slots.

17. A radio communications system as set forth in claim 16, wherein m is equal to 1≦

m≦

10.

18. A radio communications system comprising:

at least one base station comprising means for transmitting information over a first radio channel and for receiving information over a second radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the second radio channel and for receiving information over the first radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein at least said second radio channel is a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the base station from said transmitting means of a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said frame is comprised at least one second slot that is not pre-assigned to any of said plurality of user transceivers;

wherein said transmitting means of said plurality of user transceivers transmit a channel allocation request message to said base station during said at least one second slot, the transmitted channel allocation request message comprising up to m bits of data, where m<

n;

and wherein said transmitting means of multiple ones of said user transceivers transmit a channel allocation request message during said at least one second slot,

wherein said at least one second slot is frequency divided into a plurality of sub-slots.

19. A radio communications system comprising:

at least one base station comprising means for transmitting information over a first radio channel and for receiving information over a second radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the second radio channel and for receiving information over the first radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein at least said second radio channel is a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the base station from said transmitting means of a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said frame is comprised at least one second slot that is not pre-assigned to any of said plurality of user transceivers;

wherein said transmitting means of said plurality of user transceivers transmit a channel allocation request message to said base station during said at least one second slot, the transmitted channel allocation request message comprising up to m bits of data, where m<

n;

and wherein said transmitting means of multiple ones of said user transceivers transmit a channel allocation request message during said at least one second slot,

wherein said at least one second slot is code divided into a plurality of sub-slots.

20. A radio communications system comprising:

at least one base station comprising means for transmitting information over a first radio channel and for receiving information over a second radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the second radio channel and for receiving information over the first radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein at least said second radio channel is a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the base station from said transmitting means of a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said frame is comprised at least one second slot that is not pre-assigned to any of said plurality of user transceivers;

wherein said transmitting means of said plurality of user transceivers transmit a channel allocation request message to said base station during said at least one second slot, the transmitted channel allocation request message comprising up to m bits of data, where m<

n;

and wherein said transmitting means of multiple ones of said user transceivers transmit a channel allocation request message during said at least one second slot,

wherein said at least one second slot is divided into a plurality of sub-slots by a bit sequence that is assigned to individual ones of user transceivers to transmit during said at least one second slot, each of said assigned bit sequences being one of mutually orthogonal and substantially orthogonal to other assigned bit sequences.

21. A radio communications system comprising:

at least one base station comprising means for transmitting information over a first radio channel and for receiving information over a second radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the second radio channel and for receiving information over the first radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein at least said second radio channel is a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the base station from said transmitting means of a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said frame is comprised at least one second slot that is not pre-assigned to any of said plurality of user transceivers;

wherein said transmitting means of said plurality of user transceivers transmit a channel allocation request message to said base station during said at least one second slot, the transmitted channel allocation request message comprising up to m bits of data, where m<

n;

and wherein said transmitting means of multiple ones of said user transceivers transmit a channel allocation request message during said at least one second slot,

wherein said at least one second slot is divided into a plurality of sub-slots by a spreading code that is assigned to individual ones of user transceivers to transmit during said at least one second slot, each of said assigned spreading codes being one of mutually orthogonal and substantially orthogonal to other assigned spreading codes.

22. A radio communications system comprising:

at least one base station comprising means for transmitting information over a first radio channel and for receiving information over a second radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the second radio channel and for receiving information over the first radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein at least said second radio channel is a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the base station from said transmitting means of a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said frame is comprised at least one second slot that is not pre-assigned to any of said plurality of user transceivers;

wherein said transmitting means of said plurality of user transceivers transmit a channel allocation request message to said base station during said at least one second slot, the transmitted channel allocation request message comprising up to m bits of data, where m<

n;

and wherein said transmitting means of multiple ones of said user transceivers transmit a channel allocation request message during said at least one second slot,

wherein said transmitting means of each of said user transceivers transmits a radio signal with a first bandwidth during an assigned one of said first time slots, and transmits a radio signal with a second bandwidth during said at least one second slot, and wherein said second bandwidth is narrower than said first bandwidth.

23. A radio communications system comprising:

at least one base station comprising means for transmitting information over a first radio channel and for receiving information over a second radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the second radio channel and for receiving information over the first radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein at least said second radio channel is a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the base station from said transmitting means of a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said frame is comprised at least one second slot that is not pre-assigned to any of said plurality of user transceivers;

wherein said transmitting means of said plurality of user transceivers transmit a channel allocation request message to said base station during said at least one second slot, the transmitted channel allocation request message comprising up to m bits of data, where m<

n; and

wherein said transmitting means of multiple ones of said user transceivers transmit a channel allocation request message during said at least one second slot,

wherein said base station is comprised of a receiver;

an equalizer means having input coupled to an output of said receiver for equalizing a transmission received from a user transceiver during one of said plurality of first time slots; and

a plurality of correlator means individual ones of which have an input coupled to said output of said receiver for simultaneously detecting a plurality of messages received from a plurality of user transceivers during said at least one second time slot.

24. A method for operating a radio communications system, comprising the steps of:

providing at least one central transceiver comprising means for transmitting information over a first radio channel and for receiving information over a second radio channel;

providing a plurality of user transceivers each comprising means for transmitting information over the second radio channel and for receiving information over the first radio channel, the information being transmitted by each of the plurality of user transceivers in a bit serial digital format;

partitioning at least said second radio channel into a plurality of recurring frames, each of the frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

pre-assigning individual ones of a plurality of first slots to individual ones of the plurality of user transceivers for conveying communications traffic information;

simultaneously transmitting a plurality of messages to the central transceiver from individual ones of a plurality of the user transceivers during at least one second slot, the transmitted messages each comprising up to m bits of data, where m<

n; and

transmitting during a second slot an acknowledgement message to the central transceiver in response to one of a user transceiver receiving communications traffic information from the first radio channel and a user transceiver detecting an error that occurs while receiving communications traffic information from the first radio channel.

25. A radio communications system, comprising:

at least one central transceiver comprising means for transmitting information over a radio channel and for receiving information over the radio channel; and

a plurality of user transceivers each comprising means for transmitting information over the radio channel and for receiving information over the radio channel, the information being transmitted by each of said plurality of user transceivers in a bit serial digital format;

wherein said transmitting means of at least said plurality of user transceivers utilize the radio channel for transmission as a time division, multiple access radio channel characterized by a plurality of recurring frames, each of said frames comprising a plurality of equal length slots having a duration that is selected for enabling up to n bits of data to be transmitted to the central transceiver from a user transceiver;

wherein each user transceiver further comprises means for receiving a pre-assignment of an individual one of a plurality of first slots for conveying communications traffic information;

wherein said transmitting means of said plurality of user transceivers transmit a message to said central transceiver during at least one second slot, the transmitted message comprising up to m bits of data, where m<

n;

and wherein said transmitting means of multiple ones of said user transceivers transmit the message during said at least one second slot,

wherein said messages are acknowledgement messages generated by a user transceiver and transmitted by said transmitting means in response to an error that occurs while receiving communications traffic information from said radio channel, and wherein said at least one second slot is temporally divided into a plurality of sub-slots.