Selective symbol repetition for SFBC on sPDCCH
When the number of Spatial Block Coded (SBC) modulation symbols in a Physical Resource Block (PRB) is not divided evenly by the number of SBC antenna ports, an SBC coded modulation symbol of a group of SBC coded modulation symbols is repeated, where the same Resource Element (RE) location is repeated on all antennas. In some embodiments, the repeated symbol is adjacent to a modulation symbol of the group that is not repeated. In other embodiments, the repeated modulation symbol is in an adjacent subcarrier to the subcarrier that carries the modulation symbol that is repeated. RE groups with relatively larger numbers of non-zero modulation symbols on a given antenna port and PRB occupy different antenna ports in different PRBs.
1. A method, performed by a base station operative in a wireless communication network, of selectively repeating a modulation symbol in an antenna diversity transmission of a control channel, the method comprising:
dividing a plurality of Resource Elements (REs) into multiple pluralities of RE groups, wherein:
each plurality of RE groups is associated with an antenna port;
one or more RE groups of each plurality of RE groups comprise a positive number M of REs, and at least one RE group of each plurality of RE groups comprises a positive number N1 of REs; and
groups of modulation symbols correspond to the RE groups;
for each plurality of RE groups, repeating a modulation symbol of a group of modulation symbols corresponding to the RE group of N1 REs; and
transmitting the modulation symbols within each plurality of RE groups on the antenna port associated with the plurality of RE groups.
2. The method of claim 1 , wherein N1 differs from M.
3. The method of claim 1 , further comprising:
transmitting the copied modulation symbol in a subcarrier adjacent to a subcarrier in which a modulation symbol that is not copied is transmitted.
4. The method of claim 1 , wherein the copied modulation symbol occupies the last RE of the group of N1 REs, and the modulation symbol that is copied occupies a subcarrier adjacent to the subcarrier occupied by the copied modulation symbol.
5. The method of claim 1 , wherein an RE group of the plurality of RE groups comprises N2 REs, where N2 differs from N1.
6. The method of claim 1 , wherein the modulation symbols within each RE group of N1 REs are transmitted on:
a first antenna port and a first set of subcarriers comprises a first number of non-zero modulation symbols;
a second antenna port and the first set of subcarriers comprises a second number of non-zero modulation symbols;
the first antenna port and a second set of subcarriers comprises the second number of non-zero modulation symbols; and
the second antenna port and the second set of subcarriers comprises the first number of non-zero modulation symbols.
7. The method of claim 1 , further comprising:
transmitting an integer P port reference signal and the downlink control channel in a first subcarrier of an Orthogonal Frequency Division Multiplex (OFDM) symbol; and
transmitting a repeated modulation symbol of one of the RE groups of N1 REs in a second subcarrier of the OFDM symbol corresponding to a 2P port reference signal, where the 2P port reference signal would occupy the first subcarrier of the OFDM symbol.
8. A base station operative in a wireless communication network, comprising:
one or more antennas;
a transceiver operatively connected to the antennas; and
processing circuitry operatively connected to the transceiver, and operative to:
divide a plurality of Resource Elements (REs) into multiple pluralities of RE groups, wherein:
each plurality of RE groups is associated with an antenna port;
one or more RE groups of each plurality of RE groups comprise a positive number M of REs, and one RE group of each plurality of RE groups comprises a positive number N1 of REs; and
groups of modulation symbols correspond to the RE groups;
for each plurality of RE groups, repeat a modulation symbol of a group of modulation symbols corresponding to the RE group of N1 REs; and
transmit the modulation symbols within each plurality of RE groups on the antenna port associated with the plurality of RE groups.
9. The base station of claim 8 , wherein N1 differs from M.
10. The base station of claim 8 , wherein the processing circuitry is further operative to:
transmit the copied modulation symbol in a subcarrier adjacent to a subcarrier in which a modulation symbol that is not copied is transmitted.
11. The base station of claim 8 , wherein the copied modulation symbol occupies the last RE of the group of N1 REs, and the modulation symbol that is copied occupies a subcarrier adjacent to the subcarrier occupied by the copied modulation symbol.
12. The base station of claim 8 , wherein an RE group of the plurality of RE groups comprises N2 REs, where N2 differs from N1.
13. The base station of claim 8 , wherein the modulation symbols within each RE group of N1 REs are transmitted on:
a first antenna port and a first set of subcarriers comprises a first number of non-zero modulation symbols;
a second antenna port and the first set of subcarriers comprises a second number of non-zero modulation symbols;
the first antenna port and a second set of subcarriers comprises the second number of non-zero modulation symbols; and
the second antenna port and the second set of subcarriers comprises the first number of non-zero modulation symbols.
14. The base station of claim 8 , wherein the processing circuitry is further operative to:
transmit an integer P port reference signal and the downlink control channel in a first subcarrier of an Orthogonal Frequency Division Multiplex (OFDM 1 symbol; and
transmit a repeated modulation symbol of one of the RE groups of N1 REs in a second subcarrier of the OFDM symbol corresponding to a 2P port reference signal, where the 2P port reference signal would occupy the first subcarrier of the OFDM symbol.
15. A method, performed by a User Equipment (UE) operative in a wireless communication network, of receiving a control channel wherein a modulation symbol in an antenna diversity transmission of the control channel has been selectively repeated, the method comprising:
dividing a plurality of Resource Elements (REs) into multiple pluralities of RE groups, wherein:
each plurality of RE groups is associated with an antenna port,
one or more RE groups of each plurality of RE groups comprise a positive number M of REs, and one RE group of each plurality of RE groups comprises a positive number N1 of REs, and
groups of modulation symbols correspond to the RE groups; and
for each plurality of RE groups:
determining that a modulation symbol of a group of modulation symbols corresponding to the RE group of N1 REs has been copied; and
receiving the modulation symbols within each plurality of RE groups, wherein the modulation symbols within each plurality of RE groups have been transmitted on the antenna port associated with the plurality of RE groups.
16. The method of claim 15 , wherein N1 differs from M.
17. The method of claim 15 , further comprising:
receiving the copied modulation symbol in a subcarrier adjacent to a subcarrier in which a modulation symbol that is not copied was transmitted.
18. The method of claim 15 , wherein the copied modulation symbol occupies the last RE of the group of N1 REs, and the modulation symbol that is copied occupies a subcarrier adjacent to the subcarrier occupied by the copied modulation symbol.
19. The method of claim 15 , wherein an RE group of the plurality of RE groups comprises N2 REs, where N2 differs from N1.
20. The method of claim 15 , further comprising:
receiving an integer P port reference signal and the downlink control channel in a first subcarrier of an Orthogonal Frequency Division Multiplex (OFDM) symbol; and
receiving a repeated modulation symbol of one of the RE groups of N1 REs in a second subcarrier of the OFDM symbol corresponding to a 2P port reference signal, where the 2P port reference signal would occupy the first subcarrier of the OFDM symbol.