Methods and apparatus for downlink PDSCH power setting

• US 9,113,419 B2
• Filed: 08/13/2013
• Issued: 08/18/2015
• Est. Priority Date: 01/07/2008
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Zhang, Jianzhong, Pi, Zhouyue, Khan, Farooq
• Primary Examiner(s): Phillips, Hassan
• Assistant Examiner(s): Sharma, Gautam
• Application Number:
  US13/966,102
• Publication Number:
  US 20140010181A1
• Time in Patent Office: 735 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04W 52/143 Downlink power control
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/325 Power control of control or pilot channels
• CPC Class Codes: H04W 52/343 taking into account loading or congestion level
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

Methods and apparatus for transmitting power setting information in a downlink Physical Downlink Shared Channel (PDSCH) in a communication system. In this communication system, a plurality of methods for calculating traffic-to-pilot ratios (T2P) are established. In addition, a mapping scheme between a plurality of overhead signals and a plurality of reference signal (RS) overhead ratios, η_RS, and the plurality of T2P calculation methods is established. A user-specific T2P ratio P_B,k/P_RS for certain OFDM symbols, a RS overhead ratio η_RS and a calculation method selected from the plurality of T2P calculation methods are assigned to a wireless terminal. Then, an overhead signal corresponding to both of the assigned RS overhead ratio η_RS and the assigned T2P calculation method is selected in accordance with the mapping scheme and is transmitted to the wireless terminal. In addition, the user-specific traffic-to-pilot ratio P_B,k/P_RS is transmitted to the wireless terminal. The wireless terminal may calculate the traffic-to-pilot ratios across different transmission antennas and different OFDM symbols in dependence upon the received traffic-to-pilot ratio P_B,k/P_RS, and the RS overhead ratio and the T2P calculation method indicated by the RS overhead signal.

Claims

1. A method of determining a downlink transmit power from a base station at a wireless terminal, the base station and the wireless terminal having a plurality of orthogonal frequency division multiplexing (OFDM) symbols for transmission, the method comprising:

receiving a signaling parameter from the base station; and

determining a ratio of a first ratio of traffic data to pilot, T2P, for first OFDM symbols to a second ratio of T2P for second OFDM symbols based on the signaling parameter and a number of cell-specific antenna ports configured in the base station,

wherein the ratio of the first ratio to the second ratio for one cell-specific antenna port for the signal parameter 0, 1, 2, or 3 is respectively 1, 4/5, 3/5 or 2/5.

2. The method of claim 1, wherein the wireless terminal assumes that downlink reference symbol Energy Per Resource Element (EPRE) is constant across a downlink system bandwidth and is constant across all subframes until different Reference Signal (RS) power information is received.

3. The method of claim 1, wherein the first ratio or the second ratio is equal among traffic data Resource Elements (REs) for each OFDM symbol.

4. The method of claim 1, wherein the second ratio is acquired based upon a terminal-specific parameter signaled from the base station by higher layers.

5. The method of claim 1, wherein the first ratio is a ratio of a Physical Downlink Shared Channel (PDSCH) Energy Per Resource Element (EPRE) to cell-specific Reference Signal (RS) EPRE among PDSCH Resource Elements (REs) for the first OFDM symbols containing RSs, and the second ratio is a ratio of PDSCH EPRE to cell-specific RS EPRE among PDSCH REs for the second OFDM symbols not containing RSs.

6. An apparatus of a wireless terminal for determining a downlink transmit power from a base station, the base station and the wireless terminal utilizing a plurality of orthogonal frequency division multiplexing (OFDM) symbols for transmission, the apparatus comprising:

an antenna unit configured to receive a signaling parameter from the base station; and

a power setting unit configured determine a ratio of a first ratio of traffic data to pilot, T2P, for first OFDM symbols to a second ratio of T2P for second OFDM symbols, based on the signaling parameter and a number of cell-specific antenna ports configured in the base station,

wherein the ratio of the first ratio to the second ratio for one cell-specific antenna port for the signaling parameter is 0, 1, 2, or 3 is respectively 1, 4/5, 3/5, or 2/5, and

wherein the ratio of the first ratio to the second ratio for 2 or 4 of cell-specific antenna ports for the signaling parameter is 0, 1, 2, or 3 is respectively 5/4, 1, 3/4, or 1/2.

7. The apparatus of claim 6, wherein the wireless terminal assumes downlink reference symbol Energy Per Resource Element (EPRE) is constant across a downlink system bandwidth and is constant across all subframes until different Reference Signal (RS) power information is received.

8. The apparatus of claim 6, wherein the first ratio or the second ratio is equal among traffic data Resource Elements (REs) for each OFDM symbol.

9. The apparatus of claim 6, wherein the second ratio is acquired based a terminal-specific parameter signaled from the base station by higher layers.

10. The apparatus of claim 6, wherein the first ratio is a ratio of a Physical Downlink Shared Channel (PDSCH) Energy Per Resource Element (EPRE) to cell-specific Reference Signal (RS) EPRE among PDSCH Resource Elements (REs) for the first OFDM symbols containing RSs, and the second ratio is a ratio of PDSCH EPRE to cell-specific RS EPRE among PDSCH REs for the second OFDM symbols not containing RSs.

11. A method of determining a downlink transmit power for at least one wireless terminal at a base station, the base station and the wireless terminal utilizing a plurality of orthogonal frequency division multiplexing (OFDM) symbols for transmission, the method comprising:

transmitting a signaling parameter to the at least one wireless terminal in a cell by higher layers; and

transmitting traffic data by using one of a first ratio of traffic data to pilot, T2P, for first OFDM symbols and a second ratio of T2P for second OFDM symbols,

wherein a ratio of the first ratio to the second ratio is determined based on the signaling parameter and a number of cell-specific antenna ports configured in the base station,

wherein the ratio of the first ratio to the second ratio for one cell-specific antenna port for the signaling parameter is 0, 1, 2, or 3 is respectively 1, 4/5, 3/5, or 2/5, and

wherein the ratio of the first ratio to the second ratio for 2 or 4 of cell-specific antenna ports for the signaling parameter is 0, 1, 2, or 3 is respectively 5/4, 1, 3/4, or 1/2.

12. The method of claim 11, wherein the first ratio or the second ratio is equal among traffic data Resource Elements (REs) for each OFDM symbol.

13. The method of claim 11, wherein the second ratio is acquired based a terminal-specific parameter signaled from the base station by higher layers.

14. The method of claim 11, wherein the first ratio is a ratio of a Physical Downlink Shared Channel (PDSCH) Energy Per Resource Element (EPRE) to cell-specific Reference Signal (RS) EPRE among PDSCH Resource Elements (REs) for the first OFDM symbols containing RSs, and the second ratio is a ratio of PDSCH EPRE to cell-specific RS EPRE among PDSCH REs for the second OFDM symbols not containing RSs.

15. An apparatus of a base station for determining a downlink transmit power for at least one wireless terminal, the base station and the wireless terminal utilizing a plurality of orthogonal frequency division multiplexing (OFDM) symbols for transmission, the apparatus comprising:

an antenna unit configured to transmit a signaling parameter to the at least one wireless terminal in a cell by higher layers; and

a transmitter configured to transmit traffic data by using one of a first ratio of traffic data to pilot, T2P, for first OFDM symbols and a second ratio of T2P for second OFDM symbols,

wherein a ratio of the first ratio to the second ratio is determined based on the signaling parameter and a number of cell-specific antenna ports configured in the base station,

wherein the ratio of the first ratio to the second ratio for one cell-specific antenna port for the signaling parameter is 0, 1, 2, or 3 is respectively 1, 4/5, 3/5, or 2/5, and

wherein the ratio of the first ratio to the second ratio for 2 or 4 of cell-specific antenna ports for the signaling parameter is 0, 1, 2, or 3 is respectively 5/4, 1, 3/4, or 1/2.

16. The apparatus of claim 15, wherein the first ratio or the second ratio is equal among traffic data Resource Elements (REs) for each OFDM symbol.

17. The apparatus of claim 15, wherein the second ratio is acquired based a terminal-specific parameter signaled from the base station by higher layers.

18. The apparatus of claim 15, wherein the first ratio is a ratio of a Physical Downlink Shared Channel (PDSCH) Energy Per Resource Element (EPRE) to cell-specific Reference Signal (RS) EPRE among PDSCH Resource Elements (REs) for the first OFDM symbols containing RSs, and the second ratio is a ratio of PDSCH EPRE to cell-specific RS EPRE among PDSCH REs for the second OFDM symbols not containing RSs.