Method and System for Capacity and Coverage Enhancement in Wireless Networks With Relays

• US 20080260000A1
• Filed: 09/29/2005
• Published: 10/23/2008
• Est. Priority Date: 09/29/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Periyalwar, Shalini, Yanikomeroglu, Halim, Mubarek, Omer
• Granted Patent: US 8,478,283 B2
• Time in Patent Office: Days
• US Class Current: 375/133
• CPC Class Codes: H04B 1/7143 Arrangements for generation of hop patterns
• CPC Class Codes: H04B 1/715 Interference-related aspects
• CPC Class Codes: H04B 2001/7154 with means for preventing interference
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• 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 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user

Abstract

A method and system for capacity and coverage enhancement in wireless networks is provided. Each cell has a base station and in-cell relay stations. The base station includes interference avoidance/averaging mechanism, dynamic resource partitioning mechanism or a combination thereof. The interference avoidance/averaging mechanism dynamically creating a FH pattern based on interference information obtained from its serving cell. The base station may include a scheduler for dynamic resource partitioning mechanism for managing scheduling in the cell.

Claims

1. A method for capacity and coverage enhancement in a wireless network including a plurality of cells, each cell having a base station and a plurality of relay stations, the base station communicating with one or more user equipments in the cell directly or through one or more relay stations in the cell, comprising the steps of:

collecting interference information on possible interference gathered by a user equipment within a cell;

determining, base on the interference information collected within the cell, one or more frequency channels or sub-channels on which the interference is most severe; and

dynamically generating a frequency hopping (FH) pattern for the user equipment in the cell based on the one or more frequency channels or sub-channels, without any transmission coordination between difference cells.

2. A method according to claim 1, wherein the step of generating a FH includes the step of:

selectively implementing interference avoidance, interference averaging or a combination thereof based on the interference information.

3. A method according to claim 1, wherein the step of generating a FH pattern includes:

prioritizing frequencies above a performance criterion based on the interference information for each relay station and the base station; and

generating the FH pattern from the set of prioritized frequencies independently for use in each relay station neighborhood.

4. A method according to claim 3, wherein the step of generating the FH pattern from the set of prioritized frequencies includes:

generating the FH using the frequencies which are prioritized, when the possible interference includes the inter-cell interference.

5. A method according to claim 3, further comprising the step of:

at the user equipment, monitoring pathloss and reporting pathloss information associated with the pathloss, wherein the collecting step collects the pathloss information through an uplink.

6. A network system for a wireless network including a cell, the cell having a plurality of relay stations, comprising:

a base station including;

a module for collecting pathloss information associated with possible interference gathered by a user equipment in the cell, directly or through one or more relay stations in the cell;

a module for determining, based on the pathloss information reported through an uplink, one or more frequency channels or sub-channels on which the interference is significant, and selecting an algorithm; and

a module for generating a frequency hopping (FH) pattern for the user equipment in the cell using the selected algorithm, without any transmission coordination between difference cells.

7. A network system according to claim 6, wherein the generating module prioritizes frequencies above a performance criterion based on the pathloss information monitored over the range of relevant frequencies for each relay station and the base station, and generates the FH pattern independently for use in each relay station neighborhood.

8. A network system according to claim 7, wherein the generating module generates the FH pattern using the frequencies which are prioritized, when the possible interference includes the inter-cell interference.

9. A network system according to claim 7, wherein the performance criterion includes a SINR threshold.

10. A network system according to claim 7, wherein the base station includes a scheduler for allowing the base station and the relay stations to be master-slave relation.

11. A network system according to claim 10, wherein the operation of the cell is divided into a plurality of time slot types under the scheduler, the plurality of time slot types including a time slot type where the base station operates a low transmit power mode and transmits data to a user equipment in a neighborhood of the base station and the relay station transmits data to a user equipment in a neighborhood of the relay station.

12. A network system according to claim 11, wherein the plurality of time slot types includes a further time slot type wherein the base station operates a high transmit power mode and transmits to the relay station data directed to a user equipment, and the relay station receives the data from the base station.

13. A network system according to claim 12, wherein the base station transmits control and signaling messages directly to all user equipments in the cell in the further time slot type.

14. A network system for a wireless network including a cell, the cell having a plurality of relay stations, comprising:

a base station including;

a module for communicating with one or more user equipments in the cell, directly or through one or more relay stations in the cell;

a scheduler for controlling scheduling in its serving cell and determining scheduling information for the relay stations in the cell, the scheduler dividing a time into a plurality of time slot types, and dynamically allocating one or more subunits to each time slot type, the relay stations in the base station domain being synchronized with the base station;

a module for changing transmit power based on the time slot type.

15. A network system according to claim 14, wherein the time slot types are allocated to downlink communications.

16. A network system according to claim 15, wherein the time slot types are allocated to uplink communications.

17. A network system according to claim 14, wherein the base station includes a module, which is synchronized with the time slot type, for dynamically generating a frequency hopping (FH) pattern to the user equipment in the cell, without any transmission coordination between difference cells.