Terminal apparatus and method for transmitting a response signal at a terminal
A terminal includes a decoder to decode a downlink control channel transmitted on one or more control channel element(s) (CCE(s)) in a search space including a plurality of CCEs. Processing circuitry in the terminal determines an uplink channel resource index based on the one or more CCEs, the uplink channel resource index having an association with a first uplink channel transmission spreading sequence and a second different uplink channel transmission spreading sequence. A transmitter transmits a response signal on an uplink channel using the first and second uplink channel transmission spreading sequences.
1. An apparatus, comprising:
a decoder to decode a downlink control channel transmitted on one or more control channel element(s) (CCE(s)) in a search space including a plurality of CCEs;
processing circuitry to determine an uplink channel resource index based on the one or more CCEs, the uplink channel resource index having an association with a first uplink channel transmission spreading sequence and a second different uplink channel transmission spreading sequence; and
a transmitter to transmit a signal on an uplink channel using the first and second uplink channel transmission spreading sequences.
2. The apparatus in claim 1 , wherein the signal is an ACK or NACK signal.
3. The apparatus in claim 1 , wherein the first uplink channel transmission spreading sequence is one of a plurality of cyclic-shifted sequences and the second different uplink channel transmission spreading sequence is one of a plurality of orthogonal sequences.
4. The apparatus in claim 3 , wherein the plurality of cyclic-shifted sequences include one of Zero AutoCorrelation (ZAC), Generalized Chirp Like(GCL), Constant Amplitude Zero Auto correlation (CAZAC), Zadoff-Chu (ZC), or pseudo-noise sequences and the plurality of orthogonal sequences include one of block-wise, Walsh, or Fourier sequences.
5. The apparatus in claim 1 , wherein one of the first and second uplink channel transmission spreading sequences spreads the signal in a frequency domain and another of the first and second different uplink channel transmission spreading sequences spreads the signal in a time domain.
6. The apparatus in claim 1 , wherein the uplink channel is an uplink control channel, and wherein there is an association between CCE's and uplink control channels.
7. The apparatus in claim 1 , wherein the search space includes CCEs each having a corresponding CCE number which depends on a total number of CCEs in a subframe and a CCE aggregation size, and wherein at least part of the search space for the CCE aggregation size includes CCEs with consecutive CCE numbers.
8. The apparatus in claim 1 , wherein the association varies based on a control format indicator (CFI) that indicates an amount of control channel resources.
9. The apparatus in claim 8 , wherein the decoder is configured to decode the CFI which indicates a number of symbols used for control channels in a subframe, and wherein a total number of CCEs in the subframe is based on the CFI.
10. A method, comprising:
decoding a downlink control channel transmitted on one or more control channel element(s) (CCE(s)) in a search space including a plurality of CCEs;
determining an uplink channel resource index based on the one or more CCEs, the uplink channel resource index having an association with a first uplink channel transmission spreading sequence and a second different uplink channel transmission spreading sequence; and
transmitting a signal on an uplink channel using the first and second uplink channel transmission spreading sequences.
11. The method in claim 10 , wherein the signal is an ACK or NACK signal.
12. The method in claim 10 , wherein the first uplink channel transmission spreading sequence is one of a plurality of cyclic-shifted sequences and the second different uplink channel transmission spreading sequence is one of a plurality of orthogonal sequences.
13. The method in claim 12 , wherein the plurality of cyclic-shifted sequences include one of Zero AutoCorrelation (ZAC), Generalized Chirp Like(GCL), Constant Amplitude Zero Auto correlation (CAZAC), Zadoff-Chu (ZC), or pseudo-noise sequences and the plurality of orthogonal sequences include one of block-wise, Walsh, or Fourier sequences.
14. The method in claim 10 , wherein one of the first and second uplink channel transmission spreading sequences spreads the signal in a frequency domain and another of the first and second different uplink channel transmission spreading sequences spreads the signal in a time domain.
15. The method in claim 10 , wherein the uplink channel is an uplink control channel, and wherein there is an association between CCE's and uplink control channels.
16. The method in claim 10 , wherein the search space includes CCEs each having a corresponding CCE number which depends on a total number of CCEs in a subframe and a CCE aggregation size, and wherein at least part of the search space for the CCE aggregation size includes CCEs with consecutive CCE numbers.
17. The method in claim 10 , wherein the association varies based on a control format indicator (CFI) that indicates an amount of control channel resources.
18. The method in claim 17 , wherein the decoder is configured to decode the CFI which indicates a number of symbols used for control channels in a subframe, and wherein a total number of CCEs in the subframe is based on the CFI.