Sounding reference signal arrangement

1. A method, comprising:

storing data related to reference signal sequences, to form a desired cyclic shift separation between reference signal sequences, and to support a tree-based bandwidth assignment, the data being received from a user interface or from a base station;

creating an uplink message to be transmitted to the base station, the created uplink message comprises a sounding reference signal based on the stored data;

receiving uplink scheduling grant signal via downlink from the base station in response to the transmission of the uplink message;

transmitting to the base station uplink data transmission responsive to the received uplink scheduling grant signal;

forming the sounding reference signal based on existing demodulation reference signals;

selecting the sounding reference signal to support the tree-based bandwidth assignment;

adapting the sounding reference signal to provide maximum cyclic shift separation;

reserving sufficient bandwidth at least for physical uplink control channel when forming the sounding reference signal based on existing demodulation reference signal signals;

selecting a bandwidth allocation based on discrete Fourier transforms and repetition factor sizes when forming the sounding reference signal based on existing demodulation reference signal signals; and

configuring the maximum cyclic shift separation between eight cyclic shifts to result in a sounding reference signal sequence length divisible by eight when a bandwidth of the sounding reference signal is a multiple of four resource blocks.

2. The method according to claim 1 , further comprising:

determining sufficient bandwidth to reserve for the physical uplink control channel.

3. The method according to claim 2 , further comprising:

configuring at least two resource blocks to be reserved for the physical uplink control channel.

4. The method according to claim 1 , wherein the demodulation reference signal signals comprises desired discrete Fourier transforms and repetition factor sizes, and

wherein the discrete Fourier transforms sizes are two, three, or five.

5. The method according to claim 1 , further comprising:

supporting the tree-based bandwidth assignment based on a selection of sounding reference signal bandwidths in which a larger bandwidth is evenly divisible by a smaller bandwidth.

6. The method according to claim 1 , wherein the cyclic shift separation between possible cyclic shifts is maximized, and

wherein the cyclic shift is based on a sequence length and on a number of the possible cyclic shifts.

7. The method according to claim 6 , wherein the cyclic shift is a cyclic shift indicator received from base station multiplied with a sequence length and divided with the number of possible cyclic shifts, and

wherein the number of possible cyclic shifts is eight.

8. The method according to claim 1 , wherein a bandwidth of the sounding reference signal comprises a minimum of four resource blocks.

9. The method according to claim 1 , further comprising:

calculating an actual amount of cyclic shift in symbols using equation 1, which relates to a time domain generation of the cyclic shifts,

Cyclic_shift

⁢

_symbols

⁢

_SRS

=

cyclic_shift

⁢

_value

⁢

_SRS

×

SRS_length

8

wherein possible cyclic shift values (cyclic_shift_value_SRS) are, 0, 1, . . . , and 7.

10. The method according to claim 9 , further comprising:

generating corresponding cyclic shifts by utilizing basic properties of discrete Fourier transformation;

generating a cyclic shift of l by multiplying the nth element of the sequence discrete Fourier transformation with exp(j2π ln/N), where j=sqrt(−1) and N is the length of sequence; and

realizing the cyclic shift of the equation 1 in frequency domain by multiplying the nth element of the SRS sequence discrete Fourier transformation with exp(j2πn×Cyclic_shift_symbols_SRS/SRS_length)=exp(j2πn×cyclic_shift_value_SRS/8).

11. An apparatus, comprising:

a memory configured to store data related to reference signal sequences, to form a desired cyclic shift separation between reference signal sequences, and to support a tree-based bandwidth assignment, the data being received from a user interface or from a base station;

a transmitter configured to transmit to the base station a created uplink message comprising a sounding reference signal based on the stored data;

a receiver configured to receive uplink scheduling grant signal via downlink from the base station, wherein the transmitter is further configured to transmit to the base station uplink data transmission responsive to the received uplink scheduling grant signal; and

a processor configured to

form the sounding reference signal based on existing demodulation reference signal,

select the sounding reference signal to support the tree-based bandwidth assignment,

adapt the sounding reference signal to provide maximum cyclic shift separation,

reserve sufficient bandwidth for physical uplink control channel when the sounding reference signal is formed based on existing demodulation reference signal signals;

select bandwidth allocation based on a discrete Fourier transforms and repetition factor sizes when the sounding reference signal is formed based on existing demodulation reference signal signals; and

maximize cyclic shift separation between eight cyclic shifts to result in a sounding reference signal sequence length divisible by eight when a bandwidth of the sounding reference signal is a multiple of four resource blocks.

12. The apparatus according to claim 11 , wherein the processor is further configured to determine sufficient bandwidth to reserve for the physical uplink control channel.

13. The apparatus according to claim 12 , wherein two resource blocks are reserved for the protocol uplink control channel.

14. The apparatus according to claim 11 , wherein the demodulation reference signal signals comprises desired discrete Fourier transforms and repetition factor sizes, and wherein the discrete Fourier transforms sizes are two, three, or five.

15. The apparatus according to claim 11 , wherein the processor is further configured to support the tree-based bandwidth assignment based on a selection of sounding reference signal bandwidths in which a larger bandwidth is evenly divisible by any smaller bandwidth.

16. The apparatus according to claim 11 , wherein the cyclic shift separation between possible cyclic shifts is maximized, and

wherein the cyclic shift is based on a sequence length and on a number of the possible cyclic shifts.

17. The apparatus according to claim 16 , wherein the cyclic shift is a cyclic shift indicator received from a base station multiplied with a sequence length and divided with the number of the possible cyclic shifts, and

wherein the number of the possible cyclic shifts is eight.

18. The apparatus according to claim 11 , wherein a bandwidth of the sounding resource signal comprises a minimum of four resource blocks.

19. The apparatus according to claim 11 , further comprising:

a calculator configured to calculate an actual amount of cyclic shift in symbols using equation 1, which relates to a time domain generation of the cyclic shifts,

Cyclic_shift

⁢

_symbols

⁢

_SRS

=

cyclic_shift

⁢

_value

⁢

_SRS

×

SRS_length

8

wherein possible cyclic shift values (cyclic_shift_value_SRS) are, 0, 1, . . . , and 7.

20. The apparatus according to claim 11 , further comprising:

a generator configured to generate corresponding cyclic shifts by utilizing basic properties of discrete Fourier transformation;

another generator configured to generate a cyclic shift of l by multiplying the nth element of the sequence discrete Fourier transformation with exp(j2π ln/N), where j=sqrt(−1) and N is the length of sequence; and

a realizing unit configured to realize the cyclic shift of the equation 1 in frequency domain by multiplying the nth element of the SRS sequence discrete Fourier transformation with exp(j2πn×Cyclic_shift_symbols_SRS/SRS_length)=exp(j2πn×cyclic_shift_value_SRS/8).

21. An apparatus, comprising:

storing means for storing data related to reference signal sequences, to form a desired cyclic shift separation between the reference signal sequences, and to support a tree-based bandwidth assignment, the data being received from a user interface or from a base station;

transmitting means for transmitting to the base station a created uplink message comprising a sounding reference signal based on the stored data;

receiving means for receiving uplink scheduling grant signal via downlink from the base station, wherein the transmitting means for transmitting transmits to the base station uplink data transmission responsive to the received uplink scheduling grant signal;

means for forming the sounding reference signal based on existing demodulation reference signals;

means for selecting the sounding reference signal to support the tree-based bandwidth assignment;

means for adapting the sounding reference signal to provide maximum cyclic shift separation;

means for reserving sufficient bandwidth at least for physical uplink control channel when forming the sounding reference signal based on existing demodulation reference signal signals;

means for selecting a bandwidth allocation based on discrete Fourier transforms and repetition factor sizes when forming the sounding reference signal based on existing demodulation reference signal signals; and

means for configuring the maximum cyclic shift separation between eight cyclic shifts to result in a sounding reference signal sequence length divisible by eight when a bandwidth of the sounding reference signal is a multiple of four resource blocks.

22. A computer program embodied on a non-transitory computer-readable medium, the computer program being configured to control a process to perform a method, the method comprising:

storing data related to reference signal sequences, to form a desired cyclic shift separation between reference signal sequences, and to support a tree-based bandwidth assignment, the data being received from a user interface or from a base station;

creating an uplink message to be transmitted to the base station comprising a sounding reference signal based on the stored data;

receiving uplink scheduling grant signal via downlink from the base station in response to the transmission of the uplink message;

transmitting to the base station uplink data transmission responsive to the received uplink scheduling grant signal;

forming the sounding reference signal based on existing demodulation reference signals;

selecting the sounding reference signal to support the tree-based bandwidth assignment;

adapting the sounding reference signal to provide maximum cyclic shift separation;

reserving sufficient bandwidth at least for physical uplink control channel when forming the sounding reference signal based on existing demodulation reference signal signals;

selecting a bandwidth allocation based on discrete Fourier transforms and repetition factor sizes when forming the sounding reference signal based on existing demodulation reference signal signals; and

configuring the maximum cyclic shift separation between eight cyclic shifts to result in a sounding reference signal sequence length divisible by eight when a bandwidth of the sounding reference signal is a multiple of four resource blocks.