Method and system for capacity and coverage enhancement in wireless networks with relays

• US 8,478,283 B2
• Filed: 09/29/2005
• Issued: 07/02/2013
• Est. Priority Date: 09/29/2004
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Periyalwar, Shalini, Mubarek, Omer, Yanikomeroglu, Halim
• Primary Examiner(s): Hu, Jinsong
• Assistant Examiner(s): Elhag, Magdi
• Application Number:
  US11/664,135
• Publication Number:
  US 20080260000A1
• Time in Patent Office: 2,833 Days
• Field of Search: 455/422.1, 455/452.2, 455/454, 455/63.1, 455/63.3, 455/67.11, 455/71, 455427-431, 455445-451, 455/452.1, 455/464, 455/509, 455/62, 370315-317, 370/329, 370/341, 370/437
• US Class Current: 455/452.1
• 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, at least one cell having at least one 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, the method comprising:

collecting, by at least one base station in a cell of the plurality of cells, from a first user equipment in the cell interference information identifying pathloss information between the user equipment and one or more relay stations in the cell determined by the user equipment;

determining, based at least in part on the interference information, one or more noisy frequency channels or sub-channels on which interference is most severe;

dynamically generating a frequency hopping (FH) pattern that identifies a plurality of frequency channels or sub-channels for the first user equipment based on the one or more noisy frequency channels or sub-channels, wherein no noisy frequency channel or subchannel is used in the FH pattern; and

allocating one or more type slot types in a plurality of time slot types of the cell, wherein at least one time slot type comprises a time slot type where the base station operates at a low transmit power mode and transmits data to a second user equipment in a neighborhood of the base station, and at least one of the relay station transmits data to the first user equipment in a neighborhood of the relay station.

2. The method according to claim 1, wherein the step of dynamically generating the FH pattern comprises:

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

3. The method according to claim 1, wherein dynamically generating the FH pattern comprises:

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 a set of prioritized frequencies independently for use in each relay station neighborhood.

4. The method according to claim 1, wherein dynamically generating the FH pattern comprises:

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

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

5. The method according to claim 1, further comprising:

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

13. The method of claim 1, further comprising sending, by the base station, data to the first user equipment using the FH pattern without any transmission coordination between different cells of the plurality of cells.

14. The method of claim 1, wherein the first user equipment is exposed to transmissions from at least one relay station disposed in a second cell of the plurality of cells, and wherein the pathloss information comprises only pathloss information from one or more of the relay stations in the first cell.

15. The method of claim 14, wherein the first user equipment accesses data stored at the first user equipment to identify the one or more relay stations in the first cell.

16. The method of claim 1, wherein at least one frequency channel or sub-channel of the plurality of frequency channels or sub-channels in the FH pattern differs from at least one frequency channel or sub-channel in an immediately previous FH pattern used to send data from the first base station to the first user equipment.

17. The method of claim 1, wherein the FH pattern comprises a predetermined number of frequency channels or sub-channels, and the method further comprising:

maintaining a first pool of frequency channels or sub-channels comprising of unblocked frequency channels or sub-channels and a second pool of frequency channels or sub-channels comprising of blocked frequency channels or sub-channels, the blocked frequency channels or sub-channels comprising the one or more noisy frequency channels or sub-channels,

and wherein dynamically generating the frequency hopping (FH) pattern that identifies the plurality of frequency channels or sub-channels for the first user equipment based on the one or more blocked frequency channels or sub-channels further comprises;

dynamically generating the frequency hopping (FH) pattern that identifies the plurality of frequency channels or sub-channels for the first user equipment by selecting a predetermined number of frequency channels or sub-channels randomly from the first pool.

19. The method according to claim 1, wherein the plurality of time slot types includes a further time slot type, wherein the base station transmits control and signaling messages directly to all user equipments in the cell in the further time slot type.

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

a base station comprising;

a module for collecting pathloss information between a first user equipment in the cell and at least one relay station in the cell, the pathloss information determined by the first user equipment;

a module for identifying, based on the pathloss information, one or more noisy frequency channels or sub-channels on which interference is significant;

a module for generating a frequency hopping (FH) pattern for the first user equipment in the cell based on the one or more noisy frequency channels or subchannels, wherein no noisy frequency channel or sub-channel is used in the FH pattern; and

a scheduler for scheduling operation of the cell, wherein the operation of the cell is divided into a plurality of time slot types, the plurality of time slot types comprise a time slot type where the base station operates at a low transmit power mode and transmits data to a second user equipment in a neighborhood of the base station, and at least one of the relay stations transmits data to the first user equipment in a neighborhood of the relay station.

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

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

9. The network system according to claim 7, wherein the performance criterion includes a Signal to Interference and Noise Ratio (SINR) threshold.

10. The network system according to claim 6, wherein the scheduler allows the base station and at least one of the relay station to be in a master-slave relation.

11. The network system according to claim 6, wherein the plurality of time slot types includes a further time slot type wherein the base station operates at a high transmit power mode and transmits to at least one of the relay stations data directed to the first user equipment, and at least one relay station receives the data from the base station.

12. The network system according to claim 11, wherein the base station transmits control and signaling messages directly to all user equipments in the cell in the further time slot type.

18. A method for communicating with a user equipment in a cell having a base station and a plurality of relay stations, the method, comprising:

communicating, between the base station and the user equipment, via at least one relay station, first data using a first frequency hopping (FH) pattern that identifies a first plurality of frequencies;

subsequently receiving, by the base station, pathloss information determined by the user equipment, the pathloss information identifying pathloss between the user equipment and one or more relay stations of the plurality of relay stations, including the at least one relay station;

based at least in part on the pathloss information, identifying, by the base station, a set of noisy frequencies that fail to meet a predetermined criterion;

generating a new FH pattern comprising a second plurality of frequencies selected from a pool of frequencies that does not include the set of noisy frequencies, wherein at least one of the second plurality of frequencies in the new FH pattern differs from at least one of the first plurality of frequencies in the first FH pattern; and

communicating, between the base station and the user equipment, via a relay station of the plurality of relay stations, second data using the new FH pattern, wherein the communication occurs in a time slot type where the base station operates at a low transmit power mode and transmits data to at least one other user equipment in a neighborhood of the base station, and at least one of the relay station transmits data to the user equipment in a neighborhood of the relay station.