Format adaptation of a control channel for discontinuous data transmission

1. A method of operating a radio communication apparatus for use with a communication channel divided into a plurality of time slots, the method comprising:

transmitting a data signal in a first subset of the time slots;

refraining from transmitting a data signal in a second subset of the time slots; and

transmitting a control signal in each of the time slots, and

wherein the control signal comprises at least two bits constituting a power control command and a portion which is a predetermined signal; and

wherein for at least some of the second subset of time slots, the method comprises, increasing relative to the first subset of time slots, the proportion of the energy of the control signal arising from power control command bits by increasing the proportion of power control command bits and reducing, relative to the first subset of time slots, the proportion of the energy of the control signal arising from the predetermined signal portion by reducing the proportion of bits constituting the predetermined signal portion.

2. The method of claim 1 , wherein reducing the energy of the control signal comprises reducing the duration of the predetermined signal portion.

3. The method of claim 1 , wherein reducing the energy of the control signal comprises reducing the transmitted power level of the control signal.

4. The method of claim 1 , wherein reducing the energy of the control signal comprises discontinuing transmission of the control signal during a portion of the time slot.

5. The method of claim 4 , comprising, during the time slots comprising the discontinuous transmission, confining the transmission of the control signal to either or both ends of the time slot.

6. The method of claim 1 , wherein, during the at least some of the second subset of time slots, the predetermined signal portion comprises a number of bits of predetermined value, and wherein the number of bits of predetermined value is equal to the number of bits which constitute a power control command.

7. The method of claim 1 , wherein, during the at least some of the second subset of time slots, the predetermined signal portion of the control signal comprises a first plurality of bits of predetermined value, and the control signal comprises a second plurality of bits constituting a power control command, and wherein the first and second plurality of bits are interleaved.

8. The method of claim 1 , wherein the control signal comprises, for at least some of the second subset of time slots, relative to the first subset of time slots, a higher proportion of power control command bits, and wherein reducing the energy of the control signal relative to the first subset of time slots is in response to determining that the radio communication apparatus has no data to transmit in a particular time slot or group of time slots.

9. The method of claim 1 , wherein the control signal comprises, for at least some of the second subset of time slots, relative to the first subset of time slots, a higher proportion of power control command bits, and wherein reducing the energy of the control signal relative to the first subset of time slots is in response to determining that the radio communication apparatus has no permission to transmit data.

10. The method of claim 1 , wherein the control signal comprises, for at least some of the second subset of time slots, relative to the first subset of time slots, a higher proportion of power control command bits, and wherein reducing the energy of the control signal relative to the first subset of time slots is in response to determining that the radio communication apparatus has no a data signal to transmit on one channel for which the radio communication apparatus has permission to transmit, and has no permission to transmit a data signal on another channel.

11. The method of claim 1 , wherein the control signal comprises, for at least some of the second subset of time slots, relative to the first subset of time slots, a higher proportion of power control command bits, and wherein reducing the energy of the control signal relative to the first subset of time slots is in response to determining that the radio communication apparatus is in communication with a single station receiving its transmitted control signals and data, or with a plurality of such stations sharing a predetermined common property.

12. A method of operating a communication system comprising a radio communication apparatus for use with a communication channel divided into a plurality of time slots and at least one radio station for receiving signals transmitted by the radio communication apparatus, the method comprising:

transmitting a data signal in a first subset of the time slots;

refraining from transmitting a data signal in a second subset of the timeslots; and

transmitting a control signal in each of the time slots;

wherein the control signal comprises at least two bits constituting a power control command and a portion which is a predetermined signal, and

wherein for at least some of the second subset of time slots, the method comprises, increasing relative to the first subset of time slots, the proportion of the energy of the control signal arising from power control command bits by increasing the proportion of power control command bits and reducing, relative to the first subset of time slots, the proportion of the energy of the control signal arising from the predetermined signal portion by reducing the proportion of bits constituting the predetermined signal portion;

determining, at the radio station, that the radio communication apparatus has no data to transmit in a particular time slot or group of time slots, that the radio communication apparatus has no permission to transmit data, or both thereof; and

in response to said determination, transmitting an indication to the radio communication apparatus,

wherein at the radio communication apparatus, the control signal comprises a higher proportion of power control command bits, and wherein reducing the energy of the control signal is responsive to receiving the indication.

13. The method of claim 12 , wherein transmitting the indication is further dependent on a capability of a further radio station receiving signals transmitted by the radio communication apparatus.

14. The method of claim 13 , wherein the capability is the ability to control a transmitter of the further radio station in accordance with the increased proportion of the control signal which constitutes a power control command.

15. A radio communication apparatus for use with a communication channel divided into a plurality of time slots, comprising:

a transmitter configured to transmit a data signal in a first subset of a plurality of time slots and to refrain from transmitting a data signal in a second subset of the plurality of time slots;

a computer processor configured to generate a first control signal, wherein the first control signal comprises a portion which is a predetermined signal and at least two bits constituting a power control command;

the transmitter configured to transmit the first control signal in the first subset of time slots;

the computer processor configured to generate a second control signal, wherein the second control signal comprises a portion which is a predetermined signal and at least two bits constituting a power control command, and wherein the computer processor is configured to increase, relative to the first control signal, the proportion of the energy of the second control signal arising from power control command bits by increasing the proportion of power control bits, and the computer processor is configured to reduce, relative to the first control signal, the proportion of the energy of the control signal arising from the predetermined signal portion by reducing the proportion of bits constituting the predetermined signal portion, and

wherein the transmitter is configured to transmit the second control signal in at least some of the second subset of time slots and with, relative to the transmission of the first control signal, a reduced energy, wherein the reduction comprises at least the energy of the predetermined signal portion.

16. The apparatus of claim 15 , wherein the computer processor is adapted to generate the second control signal having the predetermined signal portion of shorter duration than that the predetermined signal portion of the first control signal.

17. The apparatus of claim 15 , wherein the computer processor is adapted to transmit the second control signal at a lower power level than the transmission of the first control signal.

18. The apparatus of claim 15 , wherein the computer processor is adapted to discontinue transmission of the second control signal during a portion of a time slot.

19. The apparatus of claim 18 , wherein the computer processor is adapted to confine the transmission of the second control signal to either or both ends of a time slot.

20. The apparatus of claim 15 , wherein the computer processor is adapted to generate the second control signal in which the predetermined signal portion comprises a number of bits of predetermined value, and the number of bits of predetermined value is equal to the number of bits constituting a power control command.

21. The apparatus of claim 15 , wherein the computer processor is adapted to generate the predetermined signal portion as a first plurality of bits of predetermined value, and to generate a second plurality of bits constituting a power control command, wherein the first and second plurality of bits are interleaved.

22. The apparatus of claim 15 , wherein the computer processor and the transmitter are responsive to a received indication.

23. The radio communication apparatus of claim 15 , wherein the computer processor comprises: a first control signal generator configured to generate the first control signal, and a second control signal generator configured to generate the second control signal, wherein the first and second control signal generators are different.

24. The radio communication apparatus of claim 15 , wherein the computer processor is a microcontroller.

25. A radio communication system comprising a radio communication apparatus for use with a communication channel divided into a plurality of time slots, the system comprising:

a transmitter configured to transmit a data signal in a first subset of a plurality of time slots and configured to refrain from transmitting a data signal in a second subset of the plurality of time slots;

a computer processor configured to generate a first control signal, wherein the first control signal comprises a portion which is a predetermined signal and at least two bits constituting a power control command;

the transmitter configured to transmit the first control signal in the first subset of time slots;

the computer processor configured to generate a second control signal, wherein the second control signal comprises a portion which is a predetermined signal and at least two bits constituting a power control command, and wherein the the computer processor is configured to increase, relative to the first control signal, the proportion of the energy of the second control signal arising from power control command bits by increasing the proportion of power control bits, and the computer processor is configured to reduce, relative to the first control signal, the proportion of the energy of the control signal arising from the predetermined signal portion by reducing the proportion of bits constituting the predetermined signal portion, and

the transmitter is configured to transmit the second control signal in at least some of the second subset of time slots and with, relative to the transmission of the first control signal, a reduced energy, wherein the reduction comprises at least the energy of the predetermined signal portion; and

a radio station having a controller for determining that the radio communication apparatus has no data to transmit in a particular time slot or group of time slots, that the radio communication apparatus has no permission to transmit data, or both thereof,

wherein the controller is adapted to initiate transmission of the indication in response to said determination.

26. The radio communication system of claim 25 , wherein the computer processor comprises: a first control signal generator configured to generate the first control signal, and a second control signal generator configured to generate the second control signal, wherein the first and second control signal generators are different.

27. A radio communication apparatus for use with a communication channel divided into a plurality of time slots, the apparatus comprising a computer processor configured to:

transmit a data signal in a first subset of a plurality of time slots and refraining from transmitting a data signal in a second subset of the plurality of time slots;

generate a first control signal, wherein the first control signal comprises a portion which is a predetermined signal and at least two bits constituting a power control command;

transmit the first control signal in the first subset of time slots;

generate a second control signal, wherein the second control signal comprises a portion which is a predetermined signal and at least two bits constituting a power control command;

increase, relative to the first control signal, the proportion of the energy of the second control signal arising from power control command bits by increasing the proportion of power control bits;

reduce, relative to the first control signal, the proportion of the energy of the control signal arising from the predetermined signal portion by reducing the proportion of bits constituting the predetermined signal portion; and

transmit the second control signal in at least some of the second subset of time slots and with, relative to the transmission of the first control signal, a reduced energy, wherein the reduction comprises at least the energy of the predetermined signal portion.

28. The radio communication apparatus of claim 27 , wherein the computer processor comprises: a first control signal generator configured to generate the first control signal, and a second control signal generator configured to generate the second control signal, wherein the first and second control signal generators are different.

29. The radio communication apparatus of claim 27 , wherein the computer processor is a microcontroller.

30. A radio communication apparatus for use with a communication channel divided into a plurality of time slots, comprising:

a transmitter configured to transmit a data signal in a first subset of a plurality of time slots and to refrain from transmitting a data signal in a second subset of the plurality of time slots;

a computer processor configured to generate a first control signal, wherein the first control signal comprises a portion which is a predetermined signal and at least two bits constituting a power control command;

the transmitter configured to transmit the first control signal in the first subset of time slots;

the computer processor configured to generate a second control signal, wherein the second control signal comprises a portion which is a predetermined signal and at least two bits constituting a power control command, and wherein the computer processor is configured to increase, relative to the first control signal, the proportion of the energy of the second control signal arising from power control command bits by increasing the proportion of power control bits, and the computer processor is configured to reduce, relative to the first control signal, the proportion of the energy of the control signal arising from the predetermined signal portion by reducing the proportion of bits constituting the predetermined signal portion.

31. The apparatus of claim 30 , wherein the computer processor is adapted to generate the second control signal having the predetermined signal portion of shorter duration than that the predetermined signal portion of the first control signal.

32. The apparatus of claim 30 , wherein the computer processor is adapted to transmit the second control signal at a lower power level than the transmission of the first control signal.

33. The apparatus of claim 30 , wherein the computer processor is adapted to discontinue transmission of the second control signal during a portion of a time slot.

34. The apparatus of claim 30 , wherein the computer processor is adapted to confine the transmission of the second control signal to either or both ends of a time slot.

35. The apparatus of claim 30 , wherein the computer processor is adapted to generate the second control signal in which the predetermined signal portion comprises a number of bits of predetermined value, and the number of bits of predetermined value is equal to the number of bits constituting a power control command.

36. The apparatus of claim 30 , wherein the computer processor is adapted to generate the predetermined signal portion as a first plurality of bits of predetermined value, and to generate a second plurality of bits constituting a power control command, wherein the first and second plurality of bits are interleaved.

37. The radio communication apparatus of claim 30 , wherein the computer processor is a microcontroller.