Control signalling and dynamic channel allocation in a wireless network

• US 6,977,912 B1
• Filed: 06/12/2000
• Issued: 12/20/2005
• Est. Priority Date: 06/11/1999
• Status: Expired due to Term

• Current Assignee: Axxcelera Broadband Wireless, Inc. (Moseley Wireless Solutions Group)
• Original Assignee: Axxcelera Broadband Wireless, Inc. (Moseley Wireless Solutions Group)
• Inventors: Porter, John David, Vester, Walter Charles, Freeman, Benedict Russell
• Primary Examiner(s): HO, DUC CHI
• Application Number:
  US09/592,683
• Time in Patent Office: 2,017 Days
• Field of Search: 370/328, 370/329, 370/319, 370/332, 370/330, 370/333, 370/395.2, 370/395.3, 340/3.1, 375/346, 455/115.3, 455/452.1, 455/226.2, 455/226.3, 455/450
• US Class Current: 370/329
• CPC Class Codes: H04L 2012/5607 Radio
• CPC Class Codes: H04L 2012/5625 Operations, administration and maintenance [OAM]
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04L 2012/5672 Multiplexing, e.g. coding, scrambling
• CPC Class Codes: H04W 16/04 Traffic adaptive resource partitioning
• CPC Class Codes: H04W 16/10 Dynamic resource partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/542 using measured or perceived quality
• CPC Class Codes: H04W 8/24 Transfer of terminal data

Abstract

A dynamic channel allocation method and system for use in a wireless network operates by monitoring at least the allocated channel allocated to a particular network node to generate one or more channel metrics relating to radio conditions on the channel. The metrics generated are Received signal power, signal to noise ratio of transmissions on the network and long-term mean square of the equaliser error used in each terminal. The generated metrics are communicated back to the cell access point or the network control server over a signalling channel, and a new frequency is allocated to the cell if it is determined from the metrics that the presently allocated channel is suffering interference. The signalling channel is preferably an ATM VPI/VCI pair, such that signalling messages are transmitted as ATM cells which can be communicated across the wireless channel using the sane signalling frame as is used for payload cells.

Claims

1. A method of dynamic frequency allocation for use in a wireless communications network geographically arranged into regions, each region containing at least one fixed base station and one or more subscriber terminals, communications between the fixed base station and the one or more subscriber terminals in each region taking place over an allocated one of a plurality of communications channels available for use by the network, the method comprising the steps of:

(a) monitoring the radio conditions on at least the allocated channel in each region;

(b) generating channel metrics including a metric for unrecoverable channel distortion corresponding to the monitored radio conditions on the channel; and

(c) reallocating a different channel to at least those regions where the generated channel metrics including the metric for unrecoverable channel distortion indicate that the allocated channel in those regions is suffering interference;

wherein steps (a), (b) and (c) are continuously repeated in order whereby channels may be dynamically reallocated to regions during continuous network operation.

2. A method according to claim 1, and further comprising the step of transmitting the generated channel metrics to a network control server year over a signalling channel.

3. A method according to claim 2 wherein said reallocation step (c) is performed centrally by the network control server, channel reallocation information being transmitted from the network control server to at least the fixed base station in each region over the signalling channel.

4. A method according to claim 2, wherein said signalling channel is a permanent ATM VPI/VCI pair.

5. A method according to claim 1, wherein the monitoring step (a) further includes the step of monitoring a plurality of the available channels in addition to the allocated channel in each region and the generating step (b) includes the step of generating one or more respective channel metrics, where said channel metrics include the correlation levels obtained by correlating a known training sequence corresponding to the allocated channel with each, respective training sequence corresponding to each of the plurality of monitored channels corresponding to the respective radio conditions on each of the plurality of monitored channels.

6. A system arranged to perform dynamic channel allocation for use in a wireless communications network geographically arranged into regions, each region containing at least one fixed base station and one or more subscriber terminals, communications between the fixed base stations and the one or more subscriber terminals in each region taking place over an allocated one of a plurality of wireless communications channels available for use by the network, the system comprising:

(a) monitoring means for monitoring the radio conditions on at least the allocated channel in each region;

(b) metric generation means for generating one or more channel metrics including an unrecoverable channel distortion metric corresponding to the monitored radio conditions on the channel; and

(c) channel reallocation means for reallocating a different channel to at least those regions when the generated channel metrics including the unrecoverable channel distortion metric indicate that the allocated channel in those regions is suffering interference;

wherein said monitoring means, said metric generation means and said channel reallocation means each repeat their operations in order whereby channels may be dynamically reallocated to regions during continuous network operation.

7. A system according to any of claim 6 and further comprising transmission means for transmitting the generated channel metrics to a network control server over a signalling channel.

8. A system according to claim 7 wherein said reallocation means (c are located at the network control server, channel reallocation information generated by the channel reallocation means being transmitted from the network control server to at least the fixed base station in each region over the signalling channel.

9. A system according to claim 7, wherein said signalling channel is a permanent ATM VPI/VCI pair.

10. A system according to any of claim 6, wherein the monitoring means (a) are further arranged to monitor a plurality of the available channels in addition to the allocated channel in each region and the metric generation means are further arranged to generate one or more respective channel metrics including the correlation levels obtained by correlating a known training sequence corresponding to the allocated channel with each respective training sequence corresponding to the respective radio conditions on each of the plurality of monitored channels.