Adaptive channel allocation method and apparatus for multi-slot, multi-carrier communication system

• US 5,956,642 A
• Filed: 11/25/1996
• Issued: 09/21/1999
• Est. Priority Date: 11/25/1996
• Status: Expired due to Fees

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Larsson, Per .ANG.ke, Frodigh, Carl Magnus, Almgren, Knut Magnus
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Aoki, Makoto
• Application Number:
  US08/755,966
• Time in Patent Office: 1,030 Days
• Field of Search: 455/450, 455/451, 455/452, 455/464, 455/509, 455/513, 370/329, 370/330
• US Class Current: 455/449
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels
• CPC Class Codes: H04L 5/006 Quality of the received signal, e.g. BER, SNR, water filling
• CPC Class Codes: H04L 5/0062 Avoidance of ingress interference, e.g. ham radio channels
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/541 using the level of interference

Abstract

A method and system of adaptive channel allocation in a multi-carrier, multi-slot system is provided. In the method and system a subset of M channels is chosen from a larger set of N channels available for communications on a link. As communications take place on the link, signal quality (C/I) measurements on the channels of the subset of M channels and interference (I) measurements on the channels of the group of N channels are periodically performed. The C/I and I measurements are then used to reconfigure the subset of M channels to reduce co-channel interference on the link.

Claims

1. In a Frequency Division Multiplexing (FDM) telecommunications system in which communications from a link transmitter to a link receiver are transmitted pursuant to a Time Division Multiple Access (TDMA) communication scheme over a link using a subset of a set of a plurality of channels available to the link, a method of allocating channels for communications on the link, said method comprising the steps of:

allocating a plurality of channels from said set to provide said subset, wherein each channel includes at least one carrier and at least one time slot in accordance with the TDMA communication scheme;

measuring an interference level (I) on each channel of said set;

measuring a signal quality level (C/I) on each channel of said subset;

determining a channel of said subset with a lowest signal quality level (C/I); and

determining if an unused channel exists in said set that has the interference level (I) lower than the interference level (I) of said channel of said subset with said lowest signal quality level (C/I); and

reconfiguring said subset in response to an affirmative determination.

2. The method of claim 1 in which said step of allocating comprises the step of determining said subset, said subset comprising a plurality of least interfered channels of said set.

3. The method of claim 1 in which said step of reconfiguring comprises the steps of:

removing said channel with said lowest signal quality level (C/I) from said subset in response to an affirmative determination; and

inserting said unused channel into said subset.

4. The method of claim 1 in which said step of measuring an interference level (I) further comprises the step of:

transmitting a plurality of results of said interference level (I) measurements from said link receiver to said system; and

,

said step of measuring a signal quality level (C/I) further comprises the step of;

transmitting a plurality of results of said signal quality level (C/I) measurements from said link receiver to said system.

5. The method of claim 1 in which said step of allocating comprises the steps of:

determining a candidate subset, said candidate subset comprising a plurality of least interfered channels of said set;

transmitting a subset request message from said link receiver to said system;

receiving an answer message from said system at said link receiver; and

determining in response to the received answer message whether said candidate subset was accepted as the subset of channels for said link.

6. The method of claim 5 in which said step of receiving an answer message comprises receiving a candidate subset accepted message or a channel rejected message.

7. The method of claim 6 in which said step of receiving a channel rejected message further comprises the steps of:

determining one or more next candidate channels;

transmitting one or more channel request messages from said link receiver to said system; and

repeating said steps of determining one or more next candidate channels and transmitting one or more channel request messages to said system until a complete candidate subset is accepted.

8. In a Frequency Division Multiplexing (FDM) telecommunications network in which communications from a link transmitter to a link receiver are transmitted pursuant to a Time Division Multiple Access (TDMA) communication scheme over a link using a subset of a set of a plurality of channels available to the link, a system for allocating channels for communications on the link, said system comprising:

means for allocating a plurality of channels from said set to provide said subset, wherein each channel includes at least one carrier and at least one time slot in accordance with the TDMA communication scheme;

means for measuring an interference level (I) on each channel of said set;

means for measuring a signal quality level (C/I) on each channel of said subset;

means for determining if an unused channel exists in said set that is more preferred for use on said link than any of the channels of said subset, said means for determining further comprises;

means for determining a channel of said subset with a lowest signal quality level (C/I); and

means for determining if the unused channel of said set has the interference level (I) lower than the interference level (I) of said channel of said subset with said lowest signal quality level (C/I); and

means for reconfiguring said subset in response to an affirmative determination.

9. The system of claim 8 in which said means for allocating comprises means for determining a subset, said subset comprising a plurality of least interfered channels of said set.

10. The system of claim 8 in which said means for reconfiguring comprises:

means for removing said channel with said lowest signal quality level (C/I) from said subset in response to an affirmative determination; and

means for inserting said unused channel into said subset.

11. The system of claim 8 in which said means for measuring an interference level (I) further comprises:

means for transmitting a plurality of results of said interference level (I) measurements from said link receiver to said system; and

,

said means for measuring a signal quality level (C/I) further comprises;

means for transmitting a plurality of results of said signal quality level (C/I) measurements from said link receiver to said system.

12. The system of claim 8 in which said means for allocating further comprises:

means for determining a candidate subset, said candidate subset comprising a plurality of least interfered channels of said set;

means for transmitting a subset request message from said link receiver to said system;

means for receiving an answer message from said system at said link receiver; and

means for determining, in response to the received answer message, whether said candidate subset was accepted as the subset of channels for said link.

13. The system of claim 12 in which said means for receiving an answer message comprises means for receiving a candidate subset accepted message or a channel rejected message.

14. The system of claim 13 in which the means for receiving a channel rejected message further comprises:

means for determining one or more next candidate channels;

means for transmitting one or more channel request messages from said link receiver to said system; and

means for repeating said steps of determining one or more next candidate channels and transmitting one or more channel request messages to said system until a complete candidate subset is accepted.

15. In a Frequency Division Multiplexing (FDM) telecommunications system in which communications from a link transmitter to a link receiver are transmitted pursuant to a Time Division Multiple Access (TDMA) communication scheme over a link using a subset of a set of a plurality of channels each including at least one carrier and at least one time slot, a method of allocating channels for communications on the link, said method comprising the steps of:

allocating a plurality of channels from said set to provide said subset;

measuring a received signal on each channel of said set;

determining if a candidate channel of said set exists that is more preferred for use on said link than a channel of said subset;

transmitting a channel request message from said link receiver to said system;

receiving an answer from said system at said link receiver;

determining from said answer if said candidate channel is unused;

repeating, in response to a negative determination, the steps of determining if a channel of said set exists that is more preferred, transmitting a channel request, receiving an answer, and determining from said answer, each time with a different candidate channel, until said step of determining from said answer results in an affirmative determination; and

reconfiguring said subset in response to an affirmative determination.

16. The method of claim 15 in which said step of measuring a received signal on each channel of said subset comprises the steps of:

measuring an interference level (I) on each channel of said set; and

measuring a signal quality level (C/I) on each channel of said subset; and

said step of determining if a candidate channel exists in said set that is more preferred for use on said link than a channel of said subset further comprises the steps of;

determining a channel of said subset with a lowest signal quality level (C/I); and

determining a candidate channel of said set that has an interference level (I) lower than the interference level (I) of said channel of said subset with said lowest signal quality level (C/I).

17. In a Frequency Division Multiplexing (FDM) telecommunications network in which communications from a link transmitter to a link receiver are transmitted pursuant to a Time Division Multiple Access (TDMA) communication scheme over a link using a subset of a set of a plurality of channels each including at least one carrier and at least one time slot, a system for allocating channels for communications on the link, said system comprising:

means for allocating a plurality of channels from said set to provide said subset;

means for measuring a received signal on each channel of said subset;

means for determining if a candidate channel of said set is more preferred for use on said link than a channel of said subset;

means for transmitting a channel request message from said link receiver to said system;

means for receiving an answer from said system at said link receiver; and

means for determining from said answer if said candidate channel is unused; and

means for reconfiguring said subset in response to an affirmative determination.

18. The system of claim 17 in which said means for measuring a received signal on each channel of said subset comprises:

means for measuring an interference level (I) on each channel of said set; and

means for measuring a signal quality level (C/I) on each channel of said subset; and

said means for determining if a candidate channel exists in said set is more preferred for use on said link than a channel of said subset further comprises;

means for determining a channel of said subset with a lowest signal quality level (C/I); and

means for determining a candidate channel of said set that has an interference level (I) lower than the interference level (I) of said channel of said subset with said lowest signal quality level (C/I).