METHOD FOR DOWNLINK COMMUNICATION BY MEANS OF A DOWNLINK SUPERIMPOSED RADIO SIGNAL, A BASE STATION AND A USER TERMINAL THEREFOR

• US 20120236818A1
• Filed: 11/15/2010
• Published: 09/20/2012
• Est. Priority Date: 12/10/2009
• Status: Active Grant

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Alcatel-Lucent SA (Nokia Corporation)
• Inventors: Kaminski, Stephen, Cesar, Bozo
• Granted Patent: US 9,300,377 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04B 7/0426 Power distribution
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The invention concerns a method for downlink communication between a base station and a user terminal by means of a downlink superimposed radio signal comprising downlink data for the user terminal and for at least one further user terminal that are transmitted using the same radio resources, wherein the downlink data for the user terminal are transmitted with lower power than the downlink data for the at least one further user terminal, and control information is sent in downlink from the base station to the user terminal that enables the user terminal to decode the downlink data for the at least one further user terminal, a base station, a user terminal and a communication network therefor.

Claims

1. A method for downlink communication between a base station (BS) and a user terminal (LP-UE) by means of a downlink superimposed radio signal comprising downlink data for the user terminal (LP-UE) and for at least one further user terminal (ImP-UE, HP-UE) that are transmitted using the same radio resources, wherein

the downlink data for the user terminal (LP-UE) are transmitted with lower power than the downlink data for the at least one further user terminal (ImP-UE, HP-UE),

control information is sent in downlink from the base station (BS) to the user terminal (LP-UE) that enables the user terminal (LP-UE) to decode the downlink data for the at least one further user terminal (ImP-UE, HP-UE),

the user terminal (LP-UE) successively reduces the superimposed radio signal by decoding the downlink data for the at least one further user terminal (ImP-UE, HP-UE) in the order of the downlink transmission power starting with the highest one, reconstructing a radio signal of the downlink data for the at least one further user terminal (ImP-UE, HP-UE), and subtracting the radio signal of the downlink data for the at least one further user terminal (ImP-UE, HP-UE) from the superimposed radio signal,

and the user terminal (LP-UE) decodes its own downlink data using the superimposed radio signal that has been reduced by the radio signal for the at least one further user terminal (ImP-UE, HP-UE).

2. A method according to claim 1, wherein control information for the user terminal (LP-UE) and the at least one further user terminal (ImP-UE, HP-UE) are chain-like linked by a pointer in the control information for the user terminal (LP-UE) pointing to the control information for another user terminal.

3. A method according to claim 2, wherein the control information for the user terminal (LP-UE) comprises an aggregation level range (AL) of the control information for the other user terminal.

4. A method according to claim 2, wherein a dedicated value of a pointer in a control information for a user terminal indicates that no further downlink data for a further user terminal (ImP-UE, HP-UE) are comprised in the downlink superimposed radio signal.

5. A method according to claim 1, wherein control information for the user terminal (LP-UE) comprises control information of the at least one further user terminal (ImP-UE, HP-UE) that enables the user terminal (LP-UE) to decode the downlink data for the at least one further user terminal (ImP-UE, HP-UE).

6. A method according to claim 1, wherein the base station (BS) repeatedly determines based on path losses and capabilities to decode downlink data from other user terminals the user terminal (LP-UE) and the at least one further user terminal (ImP-UE, HP-UE) to which downlink data are transmitted on the same radio resources resulting in the superimposed radio signal.

7. A method according to claim 6, wherein the user terminal (LP-UE) and the at least one further user terminal (ImP-UE, HP-UE) to which downlink data are transmitted on the same radio resources are determined for a time span of at least one subframe.

8. A method according to claim 1, wherein the control information is sent in downlink from the base station (BS) to the user terminal (LP-UE) via at least one physical downlink control channel.

9. A method according to claim 1, wherein the user terminal (LP-UE) is enabled to perform radial space-division multiple access.

10. A base station (BS) for downlink communication with a user terminal (LP-UE) by means of a downlink superimposed radio signal comprising downlink data for the user terminal (LP-UE) and for at least one further user terminal (ImP-UE, HP-UE) that are transmitted using the same radio resources, said base station (BS) comprising at least one processing means adapted to

transmit the downlink data for the user terminal (LP-UE) with lower power than the downlink data for the at least one further user terminal (ImP-UE, HP-UE),

and send control information in downlink to the user terminal (LP-UE) that enables the user terminal (LP-UE) to decode the downlink data for the at least one further user terminal (ImP-UE, HP-UE).

12. A communication network (CN) comprising at least one base station (BS) according to claim 10 and at least one user terminal (LP-UE) for downlink communication with a base station (BS) by means of a downlink superimposed radio signal comprising downlink data for the user terminal (LP-UE) and for at least one further user terminal (ImP-UE, HP-UE) that are transmitted using the same radio resources, said user terminal (LP-UE) comprising at least one processing means adapted to successively reduce the superimposed radio signal by decoding the downlink data for the at least one further user terminal (ImP-UE, HP-UE) in the order of the downlink transmission power starting with the highest one, reconstructing a radio signal of the downlink data for the at least one further user terminal (ImP-UE, HP-UE), and subtracting the radio signal of the downlink data for the at least one further user terminal (ImP-UE, HP-UE) from the superimposed radio signal, and decode its own downlink data using the superimposed radio signal that has been reduced by the radio signal for the at least one further user terminal (ImP-UE, HP-UE).

11. A user terminal (LP-UE) for downlink communication with a base station (BS) by means of a downlink superimposed radio signal comprising downlink data for the user terminal (LP-UE) and for at least one further user terminal (ImP-UE, HP-UE) that are transmitted using the same radio resources, said user terminal (LP-UE) comprising at least one processing means adapted to

successively reduce the superimposed radio signal by decoding the downlink data for the at least one further user terminal (ImP-UE, HP-UE) in the order of the downlink transmission power starting with the highest one, reconstructing a radio signal of the downlink data for the at least one further user terminal (ImP-UE, HP-UE), and subtracting the radio signal of the downlink data for the at least one further user terminal (ImP-UE, HP-UE) from the superimposed radio signal,

and decode its own downlink data using the superimposed radio signal that has been reduced by the radio signal for the at least one further user terminal (ImP-UE, HP-UE).