Channel quality indicator method
View Patent ↗The disclosed a method will work with future versions of LTE-A, be backwards compatible, and alleviate interference to signals for basic system operation. The method includes generating one or more Reference Signals associated with the one or more Channel Quality Indicators, and includes mapping the one or more Channel Quality Indicator-Reference Signals to the last symbol of the second slot of the one or more subframes.
1. An improved channel quality indicator method for determining and transmitting one or more Channel Quality Indicator Reference Signals from one or more subframes such that an associated user equipment can use the one or more Channel Quality Indicator Reference Signals to measure a Channel Quality Indicator, the subframes including first and second slots, each of the first and second slots including a plurality of symbols, and each of the first and second slots forming respectively a first resource block and a following second resource block within each of the one or more subframes, wherein the method comprises:
generating the one or more Channel Quality Indicator Reference Signals;
mapping the one or more Channel Quality Indicator-Reference Signals to the last symbol of the second slot of the one or more subframes; and
transmitting the mapped one or more Channel Quality Indicator Reference Signals from a base station to a user equipment (UE),
wherein the Channel Quality Indicator Reference Signals transmission avoids collision with a Cell-specific Reference Signal (CRS), a Dedicated Reference Signal (DRS), a Physical Broadcast CHannel (PBCH), or a synchronization signal due to
i) the Channel Quality Indicator Reference Signal always being conveyed in the last symbol of the second slot of the second resource block conveying the CQI Reference Signal, and
ii) each of said Cell-specific Reference Signal (CRS), Dedicated Reference Signal (DRS), said Physical Broadcast CHannel (PBCH), and said synchronization signal being located in another OFDM symbol in said second resource block conveying the CQI Reference Signal,
where the another OFDM symbol of said resource block is a different symbol from the last OFDM symbol in the second slot of said second resource block such that the Channel Quality Indicator Reference Signal transmission and said Cell-specific Reference Signal (CRS), Dedicated Reference Signal (DRS), said Physical Broadcast CHannel (PBCH), and said synchronization signal are always located in different OFDM symbols in the same resource block that conveys the Channel Quality Indicator Reference Signal.
2. The improved channel quality indicator method according to claim 1 , comprising, before said mapping, providing one or more subcarrier frequency offsets for the Channel Quality Indicator Reference Signals from the lowest subcarrier index in a resource block.
3. The improved channel quality indicator method according to claim 2 , wherein the subcarrier frequency offset is an integer in the range of 0 to 5.
4. The improved channel quality indicator method according to claim 1 , wherein two of the Channel Quality Indicator Reference Signals are included within the second resource block, the two Channel Quality Indicator Reference Signals being located in different sub-carriers associated with the second resource block.
5. The improved channel quality indicator method according to claim 4 , wherein the two Channel Quality Indicator Reference Signals are uniformly distributed over the sub-carriers associated with the second resource block.
6. The improved channel quality indicator method according to claim 1 ,
wherein a Coordinated Multi-Point cell is transmitted in the same second resource block as the one or more Channel Quality Indicator Reference Signals, and
said method further comprising, before said mapping, providing a first subcarrier frequency offset for a first Coordinated Multi-Point cell and a second subcarrier frequency offset for a further Coordinated Multi-Point cell.
7. The improved channel quality indicator method according to claim 1 , further comprising providing the Channel Quality Indicator Reference Signals with a transmission period, T CQI-RS .
8. The improved channel quality indicator method according to claim 7 , wherein T CQI-RS is equal to a CQI/PMI reporting period.
9. The improved channel quality indicator method according to claim 8 , wherein the CQI/PMI reporting period is any of 2 ms, 5 ms, 10 ms, 20 ms, 40 ms, 80 ms and 160 ms for Frequency Division Duplex.
10. The improved channel quality indicator method according to claim 8 , wherein the CQI/PMI reporting period is any of 1 ms, 5 ms, 10 ms, 20 ms, 40 ms, 80 ms and 160 ms for Time Division Duplex.
11. The improved channel quality indicator method according to claim 1 , further comprising providing a subframe offset for higher-layers wherein a subframe offset for the Channel Quality Indicator Reference Signals transmission is relative to subframe 0 within a frame.
12. The improved channel quality indicator method according to claim 11 , wherein said subframe offset takes the value from 0 ms to (T CQI-RS −1) ms.
13. The improved channel quality indicator method according to claim 1 , further comprising:
determining the total number of the second resource blocks that contain the Channel Quality Indicator Reference Signals based on the system bandwidth for a single component carrier, wherein the location of the resource block that contains the Channel Quality Indicator Reference Signals is determined by a parameter RB offset .
14. The improved channel quality indicator method according to claim 13 , wherein RB offset ranges from 0 to k−1, where k is a Channel Quality Indicator Reference Signals subband size.
15. The improved channel quality indicator method according to claim 14 , wherein RB offset is configured by a higher-layer.
16. The improved channel quality indicator method according to claim 14 , wherein RB offset is configured by cycling from the first resource block to the last resource block within a Channel Quality Indicator Reference Signal subband as subframe number increments.
17. The improved channel quality indicator method according to claim 1 , wherein the Channel Quality Indicator Reference Signals transmission avoids collision with a Cell-specific Reference Signal (CRS).
18. The improved channel quality indicator method according to claim 1 , wherein the Channel Quality Indicator Reference Signals transmission avoids collision with a Dedicated Reference Signal (DRS).
19. The improved channel quality indicator method according to claim 1 , wherein the Channel Quality Indicator Reference Signals transmission avoids collision with a Physical Broadcast CHannel (PBCH).
20. The improved channel quality indicator method according to claim 1 , wherein the Channel Quality Indicator Reference Signals transmission avoids collision with said Cell-specific Reference Signal (CRS), Dedicated Reference Signal (DRS), said Physical Broadcast CHannel (PBCH), and said synchronization signal.