Space Frequency block coding for PUCCH

1. A method comprising:

determining at least one control symbol and at least one channel from a channel set for the at least one control symbol representing at least one control signal for at least one port; and

determining at least one further control symbol and at least one further channel from the channel set for the at least one further control symbol for at least one further port,

wherein determining at least one further control symbol and at least one further channel comprises:

receiving an indicator of the at least one channel; and

mapping the indicator to determine the at least one further channel for the at least one further control symbol,

wherein the indicator comprises a vector having a first number of elements, the first number of elements being the number of associated channels, each element representing an indication of the symbol selected to be output on the channel associated with the element, and

wherein mapping the indicator comprises applying a mathematical function to said first number of elements to obtain an identical number of elements for a second vector for the at least one further control symbol and the at least one further channel.

2. The method as claimed in claim 1 further comprising:

transmitting the at least one control symbol over the at least one channel from a first antenna port; and

transmitting the at least one further control symbol over the at least one further channel from a second antenna port.

3. The method as claimed in claim 1 , wherein the determining at least one further control symbol and at least one further channel comprises:

pairing the channel set into pairs of channels; and

mapping comprises determining a further control symbol for the first channel of a channel set pairing by complex conjugating the at least one control symbol for the indicator indicating that the at least one channel is the second channel of the channel set pair, and a further control symbol for the second channel of the channel set pair is the product of −1 and a complex conjugation of the at least one control symbol for the indicator indicating that the at least one channel is the first channel of the channel set pair.

4. The method as claimed in claim 1 , wherein the mathematical function is:

Y ( i )=(−1) i+1 conj[ X (2 └i/ 2┘+( i+ 1 mod 2))],

where Y is the indicator for the at least one further control symbol and the at least one further channel comprising the second vector having the first number of second vector elements, and wherein each of the second vector elements represents an indication of the symbol selected to be output on the channel associated with the element for the at least one further port, and X is the vector indicator of the at least one control symbol and the at least one channel for the at least one port.

5. The method as claimed in claim 1 , wherein the channel set comprises an allocated set of channels.

6. The method as claimed in claim 5 , wherein determining the at least one further control symbol and at least one further channel comprises:

determining the allocated set of channels is an odd number of channels;

selecting a further allocated channel when the allocated set of channels is an odd number of channels, wherein the channel set further comprises the further allocated channel.

7. The method as claimed in claim 1 , wherein the channel and the further channel comprises at least one of:

frequency resources;

time period resources; and

code resources.

8. The method as claimed in claim 1 , further comprising:

receiving the at least one control symbol and at least one channel from a channel set for the at least one control symbol representing at least one control signal at a first antenna port; and

receiving the at least one further control symbol and at least one further channel from the channel set for the at least one further control symbol at at least one further antenna port, wherein the at least one further control symbol and the at least one further channel is dependent on the at least one control symbol and the at least one channel.

9. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured, with the at least one processor, to cause the apparatus at least to perform:

determining at least one control symbol and at least one channel from a channel set for the at least one control symbol representing at least one control signal for at least one port; and

determining at least one further control symbol and at least one further channel from the channel set for the at least one further control symbol for at least one further port,

wherein the at least one processor and the at least one memory are further configured, with the at least one processor, to cause the apparatus to perform determining at least one further control symbol and at least one further channel by:

receiving an indicator of the at least one channel; and

mapping the indicator to determine the at least one further channel for the at least one further control symbol,

wherein the indicator comprises a vector having a first number of elements, the first number of elements being the number of associated channels, each element representing an indication of the symbol selected to be output on the channel associated with the element, and

wherein mapping the indicator comprises applying a mathematical function to said first number of elements to obtain an identical number of elements for a second vector for the at least one further control symbol and the at least one further channel.

10. The apparatus as claimed in claim 9 , wherein the at least one processor and the at least one memory are further configured, with the at least one processor, to cause the apparatus to perform:

transmitting the at least one control symbol over the at least one channel from a first antenna port; and

transmitting the at least one further control symbol over the at least one further channel from a second antenna port.

11. The apparatus as claimed in claim 9 , wherein the at least one processor and the at least one memory are further configured, with the at least one processor, to cause the apparatus to perform:

pairing the channel set into pairs of channels; and

mapping comprises determining a further control symbol for the first channel of a channel set pairing by complex conjugating the at least one control symbol the indicator indicating that the at least one channel is for the second channel of the channel set pair, and a further control symbol for the second channel of the channel set pair is the product of −1 and a complex conjugation of the at least one control symbol the indicator indicating that the at least one channel is for the first channel of the channel set pair.

12. The apparatus as claimed in claim 9 , wherein the mathematical function is:

Y ( i )=(−1) i+1 conj[ X (2 └i/ 2┘+( i+ 1 mod 2))],

where Y is the indicator for the at least one further control symbol and the at least one further channel comprising the second vector having the first number of second vector elements, and wherein each of the second vector elements represents an indication of the symbol selected to be output on the channel associated with the element for the at least one further port, and X is the vector indicator of the at least one control symbol and the at least one channel for the at least one port.

13. The apparatus as claimed in claim 9 , wherein the channel set comprises an allocated set of channels.

14. The apparatus as claimed in claim 13 , wherein the at least one processor and the at least one memory are further configured, with the at least one processor, to cause the apparatus to perform:

determining the allocated set of channels is an odd number of channels; and

selecting a further allocated channel when the allocated set of channels is an odd number of channels, wherein the channel set further comprises the further allocated channel.

15. The apparatus as claimed in claim 9 , wherein channel and the further channel comprises at least one of:

frequency resources;

time period resources; and

code resources.

16. The apparatus as claimed in claim 9 , wherein the at least one processor and the at least one memory are further configured, with the at least one processor, to cause the apparatus to perform:

receiving the at least one control symbol and at least one channel from a channel set for the at least one control symbol representing at least one control signal at a first antenna port; and

receiving the at least one further control symbol and at least one further channel from the channel set for the at least one further control symbol at at least one further antenna port, wherein the at least one further control symbol and the at least one further channel is dependent on the at least one control symbol and the at least one channel.