Method and Apparatus for Reducing Interference in a Mobile Communications Network

• US 20110310795A1
• Filed: 11/07/2008
• Published: 12/22/2011
• Est. Priority Date: 06/23/2008
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Andersson, Rutger, Musikka, Niilo, Ovesjo, Fredrik, Karlsson, Patrik, Axelsson, Samuel, Martensson, Lars O
• Granted Patent: US 8,861,436 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04W 72/1268 of uplink data flows
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

The invention relates to a method for reducing interference between users in a mobile communications network (1) in which uplink transmissions from user equipment, UE (3), to a radio base station, RBS (5A, 5B), can be performed on at least two different carriers (C1, C2). The UE (3) support dynamic switching between CDM and TDM transmission mode and the RBS (5A, 5B) is arranged to dynamically set the mode of transmission for the UE (3). The method comprises the steps of: identifying (S200) at least a first UE as a high data rate, HDR, UE currently requiring high data transmission rate; dedicating (S201) at least one of said at least two carriers (C1, C2) to said HDR UE for at least a first period of time (T), said at least one carrier (C1, C2) hereinafter being named clean carrier, and allocating (S202) said at least first HDR UE to said clean carrier (C1, C2) during said at least first period of time (T). This method ensures that no UE operating in CDM mode is transmitting on the same carrier at the same time as the HDR UE.

Claims

1. A method for reducing interference between users in a mobile communications network in which uplink transmissions from user equipment to a radio base station can be performed on at least two different carriers, the user equipment supporting dynamic switching between code division multiplexing and time division multiplexing transmission modes and the radio base station being arranged to dynamically set the transmission mode for said user equipment, the method comprising:

identifying at least a first user equipment as a high data rate user equipment currently requiring high data transmission rate;

dedicating at least one of said at least two carriers to said high data rate user equipment for at least a first period of time, said at least one carrier referred to herein as a clean carrier, and

allocating said high data rate user equipment to said clean carrier during said at least first period of time, while ensuring that no user equipment operating in code division multiplexing mode is transmitting on the same carrier as said high data rate user equipment during said period of time.

2. The method according to claim 1, wherein a plurality of user equipment are identified as high data rate user equipment, the plurality of user equipment being scheduled in time division multiplexing mode on said clean carrier.

3. The method according to claim 1, further comprising dynamically allocating a plurality of high data rate user equipment to/from said at least one clean carrier.

4. The method according to claim 3, wherein said dynamic allocation of the plurality of high data rate user equipment to/from said at least one clean carrier is performed by means of L1 signalling.

5. The method according to claim 4, wherein said L1 signalling is performed on an enhanced dedicated channel, E-DCH, and/or an absolute grant channel, E-AGCH.

6. The method according to claim 4, wherein said L1 signalling includes information about granted transmission rate for at least one of said at least two different carriers and information indicating whether said at least one carrier is a clean carrier.

7. The method according to claim 1, wherein the clean carrier is dedicated to said high data rate user equipment only for transmissions relating to a particular service.

8. The method according to claim 1, wherein the identification of a user equipment as a high data rate user equipment is performed based on a current buffer size of said user equipment.

9. The method according to claim 8, wherein identifying a high data rate user equipment comprises receiving, at a radio base station, a request for a data transmission rate from a user equipment, which data transmission rate depends on the current buffer size of said user equipment, and identifying said user equipment as a high data rate user equipment if said data transmission rate exceeds a threshold value.

10. A radio base station in a mobile communications network, the radio base station being arranged to receive uplink transmissions from user equipment on at least two different carriers, the user equipment supporting dynamic switching between code division multiplexing and time division multiplexing transmission modes and the radio base station being arranged to dynamically set the transmission mode for said UE;

wherein said radio base station comprises a control unit configured to identify at least a first high data rate user equipment currently requiring high data transmission rate, configured to dedicate at least one of said at least two carriers to said high data rate user equipment for at least a first period of time, said at least one carrier referred to hereinafter as a clean carrier, and configured to allocate said at least first high data rate user equipment to said clean carrier during said at least first period of time, thereby ensuring that no user equipment operating in CDM mode is transmitting on the same carrier as said high data rate user equipment during said period of time.

11. A radio base station according to claim 10, said control unit further configured to schedule a plurality of user equipment UE identified as high data rate user equipment in time division multiplexing mode on said clean carrier.

12. A radio base station according to claim 10, wherein the control unit is further configured to dynamically allocate said high data rate user equipment to/from said at least one clean carrier.

13. A radio base station according to claim 12, said radio base station being adapted to use L1 signalling for the dynamic allocation of high data rate user equipment to/from said at least one clean carrier.

14. A radio base station according to claim 13, said radio base station being adapted to perform the L1 signalling on an enhanced dedicated channel, E-DCH, and/or an absolute grant channel, E-AGCH.

15. A radio base station according to claim 13, said radio base station being adapted to include, in said L1 signalling, information about granted transmission rate for at least one of said at least two different carriers and information indicating whether said at least one carrier is a clean carrier.

16. A radio base station according to claim 10, said radio base station being adapted to identify a user equipment as a high data rate user equipment based on a current buffer size of said user equipment.

17. A radio base station according to claim 16, said radio base station being adapted to receive a request for a certain data transmission rate from a user equipment, which data transmission rate depends on the current buffer size of said user equipment, and identify said user equipment as a high data rate user equipment if said data transmission rate exceeds a certain threshold value.

18. An RBS according to claim 10, said radio base station comprising a Node-B in a Universal Mobile Telecommunications System network.