METHODS AND ARRANGEMENTS IN A WIRELESS COMMUNICATION SYSTEM

• US 20160119048A1
• Filed: 01/11/2016
• Published: 04/28/2016
• Est. Priority Date: 03/30/2011
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Kazmi, Muhammad, Miao, Qingyu, LIU, JINHUA
• Granted Patent: US 9,647,744 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0619 using feedback from receiving side feedback signaling for adaptive modulation/coding H04L1/0001
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0673 using feedback from receiving side
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 52/04 TPC
• CPC Class Codes: H04W 52/06 TPC algorithms
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/221 using past power control commands
• CPC Class Codes: H04W 56/0065 using measurement of signal travel time
• CPC Class Codes: H04W 88/02 Terminal devices

Abstract

Method and arrangement in a user equipment for adjusting signals transmitted in uplink to a network node, based on a feedback value received from the network node. The method comprises transmitting a signal, to be received by the network node. Further, the method comprises receiving a feedback signal from the network node, providing feedback on the transmitted signal. In addition, the method comprises obtaining a value of a time delay of the received feedback signal. Furthermore, the method comprises adjusting signals transmitted in the uplink according to the received feedback signal, wherein compensation is made for the obtained time delay value of the received feedback signal.

Claims

1. A method in a user equipment (110) for adjusting signals transmitted in uplink to a network node (120), based on a feedback value received from the network node (120), the method comprising

transmitting (501) a signal, to be received by the network node (120),

receiving (502) a feedback signal from the network node (120), providing feedback on the transmitted (501) signal,

obtaining (503) a value of a time delay of the received (502) feedback signal, and

adjusting (504) signals transmitted in the uplink based on the value of the time delay of the feedback signal, wherein compensation is made for the obtained (503) time delay value of the received (502) feedback signal.

2. The method according to claim 1, wherein the time delay value of the received (502) feedback signal is the difference in time between the moment when the user equipment (110) transmits (501) the uplink signal and the moment when the user equipment (110) receives (502) the feedback signal from the network node (120).

3. The method according to any of claim 1 or claim 2, wherein obtaining (503) the value of the time delay of the received (502) feedback signal comprises

transmitting a signal in the uplink at a transmission power level associated with a feedback reference value,

receiving a feedback value from the network node (120), providing feedback on the transmitted uplink signal,

comparing the feedback reference value with the received feedback value, and if the feedback reference value corresponds to the received feedback value,

determining the value of a time delay of the received (502) feedback signal to be the difference in time between the transmission of the uplink signal and the reception of the feedback value.

4. The method according to any of claims 1-3, wherein obtaining (503) the value of the time delay of the received (502) feedback signal comprises

transmitting a sequence of uplink signals over a control channel at different transmission power levels P=(p₁, p₂, . . . , p_N) associated with a Transmit Power Control reference sequence TPC_ref=(r₁, r₂, . . . , r_N),

receiving, from the network node (120), a sequence of Transmit Power Control commands TPC_set=(TPC₁, TPC₂, . . . , TPC_Q) such that Q>

N, triggered by the transmitted sequence of uplink signals,

calculating a correlation sequence C=(c₀, c₁, . . . , c_Q-N) between TPC_ref and TPC_set such that

5. The method according to any of claims 1-4, wherein no transmission power adjustment is made at the user equipment (110) due to any Transmit Power Control commands received from the network node (120) during a period when the user equipment (110) is obtaining (503) the time delay value of the received (502) feedback signal.

6. The method according to any of claims 1-5, wherein the obtaining (503) of the value of the time delay of the received (502) feedback signal is triggered by any of:

a request received from the network node (120);

a handover event;

a certain time interval has passed since the previous time delay value was obtained;

periodically, where the period is predetermined or configured by the network node (120);

the user equipment (110) is set into Open Loop Transmit Diversity mode, such as Open Loop Antenna Switching mode or Open Loop Beam Forming mode;

signal processing delay for generation of Transmit Power Control commands in the network node (120) is to be changed;

active time of the user equipment (110) in Open Loop Transmit Diversity mode is longer than a threshold time;

a change of best uplink cell of the user equipment (110) in Open Loop Transmit Diversity mode is made;

user equipment speed is above a threshold over a time interval;

received signal quality in the uplink and/or in the downlink is worse than a threshold over a time interval.

7. The method according to any of claims 4-6, wherein the sequence of uplink signals to be transmitted at different transmission power levels associated with the reference sequence is pre-determined and stored in a memory (625) of the user equipment (110).

8. The method according to any of claims 4-6, wherein the sequence of uplink signals to be transmitted at different transmission power levels associated with the reference sequence is configured by the network node (120).

9. The method according to any of claims 1-8, wherein obtaining (503) the value of the time delay of the received (502) feedback signal comprises receiving at least a component of the time delay value of the received (502) feedback signal from the network node (120).

10. The method according to any of claims 1-9, wherein

the user equipment (110) comprises at least two transmission antennas (111, 112) whereby one transmission antenna (111) of the at least two transmission antennas (111, 112) is alternately used for uplink transmission while the other transmission antenna (112) of the at least two transmission antennas (111, 112) is not used for uplink transmission at the same time, and wherein

the user equipment (110) is configured for uplink transmit diversity by Open Loop Antenna Switching, and wherein

signals transmitted in the uplink are adjusted (504) by selecting one transmission antenna (111) of the at least two transmission antennas (111, 112) for the uplink transmission.

11. The method according to any of claims 1-10, wherein

the obtained (503) time delay value is used, when adjusting (504) the signals transmitted in the uplink, for determining if the received (502) feedback signal is related to the uplink signal transmitted (501) on the transmission antenna (111) used for uplink transmission, and wherein

signals transmitted in the uplink are adjusted (504) by selecting one transmission antenna (111) of the at least two transmission antennas (111, 112) to be used for uplink transmission, based on the received (502) feedback signal related to the transmission antenna (111) used for uplink transmission.

12. The method according to any of claims 1-9, wherein

the user equipment (110) comprises at least two transmission antennas (111, 112), wherein uplink transmission is performed on the at least two transmission antennas (111, 112), transmitting the same signal simultaneously by adjusting a phase difference between the signals transmitted by the at least two antennas (111, 112), such that a beam of the transmitted signal is created in certain direction, and wherein

the user equipment (110) is configured for uplink transmit diversity by Open Loop Beam Forming, and wherein

signals transmitted in the uplink are adjusted (504) by selecting beam direction or phase difference between the signals transmitted by the at least two transmission antennas (111, 112).

13. The method according to claim 12, wherein

the obtained (503) time delay value is used when adjusting (504) signals transmitted in the uplink, for determining if the received (502) feedback signal is related to the uplink signal transmitted (501) at the currently used phase difference between the signals transmitted by the at least two transmission antennas (111, 112), and wherein

signals transmitted in the uplink are adjusted (504) by selecting beam direction, or phase difference, based on the received (502) feedback signal related to the currently used phase difference between the signals transmitted by the at least two transmission antennas (111, 112).

14. The method according to any of claims 1-13, wherein the signals transmitted in the uplink are adjusted (504) by adjusting the transmission power of the user equipment (110) according to a Transmit Power Control command, received from the network node (120), with compensation made for the obtained (503) time delay value of the received (502) feedback signal.

15. An arrangement (600) in a user equipment (110) for adjusting signals transmitted in the uplink to a network node (120), based on a feedback value received from the network node (120), the arrangement (600) comprising

a transmitter (610), configured to transmit a signal, to be received by the network node (120),

a receiver (620), configured to receive a feedback signal from the network node (120), providing feedback on the transmitted signal,

a processing circuit (630), configured to obtain a value of a time delay of the received feedback signal, and to adjust signals transmitted in the uplink based on the value of the time delay of the feedback signal, wherein compensation is made for the obtained time delay value of the received feedback signal.

16. The arrangement (600) according to claim 15, further comprising

a memory (625) configured to store a pre-determined sequence of uplink signals to be transmitted at different transmission power levels associated with a reference sequence.

17. The arrangement (600) according to any of claim 15 or claim 16, further comprising

a first transmission antenna (111), and a second transmission antenna (112), which transmission antennas (111, 112) are configured to operate in Open Loop Transmit Diversity mode, such as Open Loop Antenna Switching mode or Open Loop Beam Forming mode.

18. A method in a network node (120) for providing a value of a time delay of a feedback signal transmitted to a user equipment (110) for enabling adjustment of signals transmitted in the uplink by the user equipment (110), based on a feedback value provided by the network node (120), the method comprises

determining (701) that the user equipment (110) is to adjust signals transmitted in the uplink, based on the value of the time delay of the feedback signal, and

transmitting (704) a request to be received by the user equipment (110), triggering the user equipment (110) to determine the time delay value of the feedback signal.

19. The method according to claim 18, further comprising

measuring (702) at least a component of the time delay value of the feedback signal transmitted to the user equipment (110), and

providing (703) the measured time delay value of the feedback signal transmitted to the user equipment (110), or a component thereof, to the user equipment (110).

20. An arrangement (800) in a network node (120) for providing a value of a time delay of a feedback signal transmitted to a user equipment (110) for enabling adjustment of signals transmitted in the uplink by the user equipment (110), based on a feedback value provided by the network node (120), the arrangement (800) comprises

a processing circuit (820), configured to determine that the user equipment (110) is to adjust signals transmitted in the uplink, based on the value of the time delay of the feedback signal, and

a transmitter (830), configured to transmit a request to be received by the user equipment (110), triggering the user equipment (110) to determine the time delay value of the feedback signal.