Method and apparatus for network wide adaptive resource allocation for OFDMA/TDMA networks

• US 20090080375A1
• Filed: 12/22/2006
• Published: 03/26/2009
• Est. Priority Date: 12/22/2005
• Status: Active Grant

• Current Assignee: WiChorus, Inc. (Infinera Corp.)
• Original Assignee: WiChorus, Inc. (Infinera Corp.)
• Inventors: Jalil, Rehan, Ergen, Mustafa, Mak, Tony
• Granted Patent: US 8,284,715 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 24/02 Arrangements for optimising operational condition
• CPC Class Codes: H04W 28/16 Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
• CPC Class Codes: H04W 72/563 of the wireless resources

Abstract

In this invention, adaptive resource allocation is proposed. A resource is divided into Blocks and each base station is assigned a Block for its terminals that are in the interference region, and another Block for its terminals that are not in the interference region. Blocks other than these two are not used by the base station. Bordering base stations does not use the same Block if they have any terminal in the shared interference region.

Another embodiment of the invention proposes resource sizing along with load balancing scheme. Resource sizing is defined as determining the size of the resources allocated for each Block. This is adaptable and can change over time according to topology. Another embodiment of the invention proposes a handover method for some terminals in order to increase the Block utilization by handing a terminal over another base station. Final embodiment of the invention proposes an adaptive control scheme that defines multiple policies for different topologies. Selecting a policy is determined by the given topology as well as the output utilization where utilization is defined as the allocated resource over total resource per Block together with demanded resource over total resource per Block.

Claims

1. A method for allocating network wide adaptive resources, comprising the steps of

providing a central controller, a plurality of base stations in wireless communication with said central controller;

and a plurality of subscriber units in communication with said base stations;

said base station including a micro scheduler having traffic allocation logic to allocate OFDMA frame, said central controller including a macro level scheduler that policies the traffic and being forwarded to each base station, whereby micro and macro scheduler controls and optimize radio frequency (RF) and backhoul resources in unison;

identifying mobile subscribers in a first overlapping region of two or more base stations by said central controller;

assigning a second region in the OFDMA to a particular base station,

blocking out said second region for other base stations in conflict with said base station.

3. The network defined in claim 1 wherein the resource management is composed of conflict management and resource allocation. Conflict management is responsible to identify the mobile stations that are in the overlapping region of two or more base stations. Conflict management assigns a region in the OFDMA to a particular BS and blocks out the aforementioned region for the other BSs that are in conflict with the said MS. A MS in conflict is served with the said region only.

Resource allocation assigns a region to each station and an allocation is given to each terminal within that region for its traffic demand. Procedure is as follows;

A (mobile) terminal sends the scanning report which contains the signal level to neighboring base stations;

conflict management methodology identifies the conflicted base stations through the mobile stations that can hear more than one base station;

conflict management methodology creates regions within the OFDMA frame to resolve the conflicts;

conflict management methodology assigns a region to a base station and informs other neighboring base stations in the same conflict to block out that region;

resource allocation methodology then assigns terminals to a region.

4. The resource management method defined in claim 1 can be centralized or split in the said network. The centralized management requires central controller to handle the entire resource management across the entire network. Conflict management and resource allocation resides in the central controller.

5. Following claim 3, the split-resource management has macro and micro resource manager. Macro resource manager consists of

a. Interference detection methodology which identifies the conflict regions with respect to scanning reports or connectivity table.

b. Resource partitioning and assignment methodology partitions the blocks. Some blocks are used by all base stations and some blocks are assigned to one base station among the base stations that are in conflict.

c. Cost association methodology assigns a cost weight to each terminal depending on its characteristics.

d. Terminal association methodology assigns each terminal to a base station.

e. Allocation fine tuning methodology does local resource optimization by balancing terminals from a heavily loaded base station to its lightly load neighbors, thereby the resource available to that local region is further increased.

f. Resource sizing methodology computes the total cost of each block and resize the blocks according to the method described in the embodiment.

Micro resource manager in each base station allocates bandwidth to each terminal depending on the policies defined in the embodiment of the invention.

Method has system update mechanism that resizes the blocks depending on the changes in the topology. System update consists of terminal assignment which is a decision mechanism to associate a terminal to a base station. Association takes place to reduce conflict regions;

periodic resource sizing which is an event that takes place periodically regarding traffic of each terminal;

event based resource management is a load balancing algorithm that kicks in when the system is overloaded and network unbalanced

2. A network comprising:

a central controller;

a plurality of base station units to communicate with the central controller; and

a plurality of subscriber units to communicate with the base station using an orthogonal frequency-division multiple-access (OFDMA) protocol;

the base station includes a micro scheduler that have the traffic allocation logic to allocate OFDMA frame;

the central controller includes a macro level scheduler that policies the traffic that is forwarded to each BS. Together micro and macro scheduler controls and optimize radio frequency (RF) and backhoul resources.

6. Apparatus for allocating network wide adaptive resource, comprising:

a central controller,

a plurality of base stations in wireless communication with said central controller;

a plurality of subscriber units in communication with said base stations;

said base station including a micro scheduler having traffic allocation logic to allocate OFDMA frame, said central controller including a macro level scheduler that policies the traffic and being forwarded to each base station, whereby micro and macro scheduler controls and optimize radio frequency (RF) and backhoul resources in unison;

means for identifying mobile subscribers in a first overlapping region of two or more base stations by said central controller;

means for assigning a second region in the OFDMA to a particular base station, means for blocking out said second region for other base stations in conflict with said base station.