Frequency hopping pattern and arrangement for sounding reference signal

1. A method, comprising:

forming, by a processor user equipment, a frequency hopping position of the a sounding reference signal based on a hopping pattern;

configuring, at the user equipment, the hopping pattern of the sounding reference signal to utilize a tree assignment for a frequency allocation of the sounding reference signal and to support at least one frequency band branch per layer;

configuring, at the user equipment, the hopping pattern of the sounding reference signal to provide consecutive sounding reference signals on widely separated frequency allocations;

defining, at the user equipment, a frequency-domain starting position for a hopping sounding reference signal based on a similar equation as the sounding reference signal without frequency hopping; and

defining, at the user equipment, the hopping pattern in terms of n l for tree layers 1 and above:

n l =F l,t +n l,orig mod N l , where n l,orig is a reference value of an allocation index for tree layer 1 l,

where N l is a number of new branches per a branch on an assignment tree layer 1 l, where t is a time index for the sounding reference signal and is relative on a common reference frame and subframe number and is a function of the current frame number, the subframe number and a sounding reference signal period, n l is the sounding reference signal frequency position index on tree layer 1 l, and F l,t is a sounding reference signal position.

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

defining a frequency-domain starting position of k 0 by

k

0

=

k

0

′

+

∑

l

=

0

L

SRS

⁢

B

l

⁢

n

l

,

where k′ 0 is an offset in sub-carriers related to a used repetition factor comb, L SRS is the index of the assigned sounding reference signal bandwidth value, B l is the sounding reference signal bandwidth in subcarriers on tree layer 1 , and n l is the sounding reference signal frequency position index on tree layer 1 l.

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

defining F l,t as

F

l

,

t

=

N

l

/

2

⁢

⌊

t

⁢

⁢

mod

⁢

∏

l

′

=

0

l

⁢

⁢

N

l

′

∏

l

′

=

0

l

-

1

⁢

⁢

N

l

′

⌋

+

⌊

t

⁢

⁢

mod

⁢

∏

l

′

=

0

l

⁢

⁢

N

l

′

2

⁢

∏

l

′

=

0

l

-

1

⁢

⁢

N

l

′

⌋

 when N l is even; and

defining F l,t as F l,t =└N l /2┘└t/Π l′=0 l−1 N l′ ┘ when N l is odd.

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

defining the frequency hopping of sounding reference signal only for tree layers 1 l min and above; and

defining the hopping pattern in terms of n l for tree layers 1 l min and above:

n l =F l,t +n l,orig mod N l , where n l,orig is a reference value of an allocation index for tree layer 1 l,

where N l is a number of new branches per a branch on an assignment tree layer 1 l, where t is a time index for the sounding reference signal and is relative on a common reference frame and subframe number and is a function of the current frame number, the subframe number and a sounding reference signal period.

5. The method according to claim 4 , further comprising:

defining F l,t as F l,t =0 when 1 l< 1 l min ;

defining F l,t as

F

l

,

t

=

N

l

/

2

⁢

⌊

t

⁢

⁢

mod

⁢

∏

l

′

=

l

min

-

1

l

⁢

⁢

N

lr

∏

l

′

=

l

min

-

1

l

-

1

⁢

⁢

N

lr

⌋

+

⌊

t

⁢

⁢

mod

⁢

∏

l

′

=

1

min

-

1

l

⁢

⁢

N

lr

2

⁢

∏

l

′

=

l

min

-

1

l

-

1

⁢

⁢

N

lr

⌋

 when 1 l is equal to or larger than 1 l min and when N l even; and

defining F l,t as

F

l

,

t

=

⌊

N

l

/

2

⌋

⁢

⌊

t

/

∏

l

′

=

l

min

-

1

l

-

1

⁢

⁢

N

lr

⌋

 when 1 l is equal to or larger than 1 l min and when N l odd,

where N l is a number of new branches per a branch on an assignment tree layer 1 l, except for 1 l min −1 for which N l min −1 =1 regardless of the number of new branches on tree layer 1 l min −1.

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

receiving a selection between the a frequency hopping and the a non-frequency hopping sounding reference signal,

wherein the sounding reference signal is configured with the frequency hopping or without the frequency hopping,

wherein the selection of the frequency hopping and the non-frequency hopping sounding reference signal is specific to a user equipment or to all user equipments within a cell.

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

receiving a radio resource control signal from an apparatus, the radio resource control signal is a sounding reference signal configuration signalling;

transmitting an uplink message to the apparatus including an allocated sounding reference signal based on data in the radio resource control signal.

8. An apparatus, comprising: a processor configured to process frequency hopping position of the sounding reference signal based on a hopping pattern, wherein the hopping pattern of the sounding reference signal is configured to utilize a tree assignment for a frequency allocation of the sounding reference signal and to support at least one frequency band branch per layer, to provide consecutive sounding reference signals on widely separated frequency allocations, to define a frequency-domain starting position for a hopping sounding reference signal based on a similar equation as the sounding reference signal without frequency hopping, and to define the hopping pattern in terms of n l for tree layers 1 and above: n l =F l,t +n l,orig mod N l , where n l,orig is a reference value of an allocation index for tree layer l, where N l is a number of new branches per a branch on an assignment tree layer l, where t is a time index for the sounding reference signal and is relative on a common reference frame and subframe number and is a function of the current frame number, the subframe number and a sounding reference signal period, n l is the sounding reference signal frequency position index on tree layer l and F l,t is a sounding reference signal position.

9. The apparatus according to claim 8 , wherein the processor is further configured to define a frequency-domain starting position of k 0 by

k

0

=

k

0

′

+

∑

l

=

0

L

SRS

⁢

B

l

⁢

n

l

,

where k′ 0 is an offset in sub-carriers related to a used repetition factor comb, L SRS is the index of the assigned sounding reference signal bandwidth value, B l is the sounding reference signal bandwidth in subcarriers on tree layer l, and n l is the sounding reference signal frequency position index on tree layer l.

10. The apparatus according to claim 8 , wherein the processor is further configured to

define F l,t as

F

l

,

t

=

N

l

/

2

⁢

⌊

t

⁢

⁢

mod

⁢

∏

l

′

=

0

l

⁢

⁢

N

l

′

∏

l

′

=

0

l

-

1

⁢

⁢

N

l

′

⌋

+

⌊

t

⁢

⁢

mod

⁢

∏

l

′

=

0

l

⁢

⁢

N

l

′

2

⁢

∏

l

′

=

0

l

-

1

⁢

⁢

N

l

′

⌋

 when N l is even; and

define F l,t as F l,t =└N l /2┘└t/Π l′=0 l−1 N l′ ┘ when N l is odd.

11. The apparatus according to claim 8 , wherein the processor is further configured to

define the frequency hopping of sounding reference signal only for tree layers l min and above; and

define the hopping pattern in terms of n l for tree layers l min and above:

n l =F l,t n l,orig mod N l , where n l,orig is a reference value of an allocation index for tree layer l,

where N l is a number of new branches per a branch on an assignment tree layer l, where t is a time index for the sounding reference signal and is relative on a common reference frame and subframe number and is a function of the current frame number, the subframe number and a sounding reference signal period.

12. The apparatus according to claim 11 , wherein the processor is further configured to

define F l,t as F l,t =0 when l<l min ;

define F l,t as

F

l

,

t

=

N

l

/

2

⁢

⌊

t

⁢

⁢

mod

⁢

∏

l

′

=

l

min

-

1

l

⁢

⁢

N

l

′

∏

l

′

=

l

min

-

1

l

-

1

⁢

⁢

N

l

′

⌋

+

⌊

t

⁢

⁢

mod

⁢

∏

l

′

=

l

min

-

1

l

⁢

⁢

N

l

′

2

⁢

∏

l

′

=

l

min

-

1

l

-

1

⁢

⁢

N

l

′

⌋

when l is equal to or larger than l min and when N l even; and

define as F l,t as F l,t =└N l /2┘└t/Π l′=l min −1 l−1 N l′ ┘ when l is equal to or larger than l min and when N l odd,

where N l is a number of new branches per a branch on an assignment tree layer l, except for l min −1 for which N l min −1 =1 regardless of the number of new branches on tree layer l min −1.

13. The apparatus according to claim 8 , further comprising:

a receiver configured to receive a selection between the frequency hopping and the non-frequency hopping sounding reference signal,

wherein the sounding reference signal is configured with the frequency hopping or without the frequency hopping,

wherein the selection of the frequency hopping and the non-frequency hopping sounding reference signal is specific to a user equipment or to all user equipments within a cell.

14. The apparatus according to claim 8 , further comprising:

a receiver configured to receive a receiving a radio resource control signal from another apparatus, the radio resource control signal is a sounding reference signal configuration signalling;

a transmitter configured to transmit an uplink message to the other apparatus including an allocated sounding reference signal based on data in the radio resource control signal.

15. A non-transitory computer-readable medium including a computer program, wherein the computer program is configured to control a processor to perform a method, comprising:

forming a frequency hopping position of the a sounding reference signal based on a hopping pattern;

configuring the hopping pattern of the sounding reference signal to utilize a tree assignment for a frequency allocation of the sounding reference signal and to support at least one frequency band branch per layer;

configuring the hopping pattern of the sounding reference signal to provide consecutive sounding reference signals on widely separated frequency allocations;

defining a frequency-domain starting position for a hopping sounding reference signal based on a similar equation as the sounding reference signal without frequency hopping; and

defining the hopping pattern in terms of n l for tree layers 1 and above:

n l =F l,t +n l,orig mod N l , where n l,orig is a reference value of an allocation index for tree layer 1 l,

where N l is a number of new branches per a branch on an assignment tree layer 1 l, where t is a time index for the sounding reference signal and is relative on a common reference frame and subframe number and is a function of the current frame number, the subframe number and a sounding reference signal period, n 1 n l is the sounding reference signal frequency position index on tree layer 1 l and F l,t is a sounding reference signal position.

16. An apparatus, comprising: forming means for forming a frequency hopping position of the sounding reference signal based on a hopping pattern; configuring means for configuring the hopping pattern of the sounding reference signal to utilize a tree assignment for a frequency allocation of the sounding reference signal, to support at least one frequency band branch per layer, and to provide consecutive sounding reference signals on widely separated frequency allocations; defining means for defining a frequency-domain starting position for a hopping sounding reference signal based on a similar equation as the sounding reference signal without frequency hopping and for defining the hopping pattern in terms of n l for tree layers 1 and above: n 1 =F l,t +n l,orig mod N l , where n l,orig is a reference value of an allocation index for tree layer l, where N l is a number of new branches per a branch on an assignment tree layer l, where t is a time index for the sounding reference signal and is relative on a common reference frame and subframe number and is a function of the current frame number, the subframe number and a sounding reference signal period, n l is the sounding reference signal frequency position index on tree layer l and F l,t is a sounding reference signal position.

17. A method, comprising:

forming, by a processor user equipment, a frequency hopping position of the a sounding reference signal based on a hopping pattern;

configuring, at the user equipment, the hopping pattern of the sounding reference signal to utilize a tree assignment for a frequency allocation of the sounding reference signal and to support at least one frequency band branch per layer;

configuring, at the user equipment, the hopping pattern of the sounding reference signal to provide consecutive sounding reference signals on widely separated frequency allocations;

defining, at the user equipment, a frequency-domain starting position for a hopping sounding reference signal based on a similar equation as the sounding reference signal without frequency hopping;

defining, at the user equipment, the hopping pattern in terms of n l for tree layers 1 and above:

n l =F l,t +n l,orig mod N l , where n l,orig is a reference value of an allocation index for tree layer 1 l,

where N l is a number of new branches per a branch on an assignment tree layer 1 l, where t is a time index for the sounding reference signal and is relative on a common reference frame and subframe number and is a function of the current frame number, the subframe number and a sounding reference signal period, n l is the sounding reference signal frequency position index on tree layer 1 l, and F l,t is a sounding reference signal position;

receiving, at the user equipment, a radio resource control signal from an apparatus, the radio resource control signal is a sounding reference signal configuration signalling; and

transmitting, at the user equipment, an uplink message to the apparatus including an allocated sounding reference signal based on data in the radio resource control signal.

18. An apparatus, comprising: a processor configured to process frequency hopping position of the sounding reference signal based on a hopping pattern, wherein the hopping pattern of the sounding reference signal is configured to utilize a tree assignment for a frequency allocation of the sounding reference signal and to support at least one frequency band branch per layer, to provide consecutive sounding reference signals on widely separated frequency allocations, to define a frequency-domain starting position for a hopping sounding reference signal based on a similar equation as the sounding reference signal without frequency hopping, and to define the hopping pattern in terms of n l for tree layers 1 and above: n 1 =F 1,t +n l,orig mod N l , where n l,orig is a reference value of an allocation index for tree layer l, where N l is a number of new branches per a branch on an assignment tree layer l, where t is a time index for the sounding reference signal and is relative on a common reference frame and subframe number and is a function of the current frame number, the subframe number and a sounding reference signal period, n l is the sounding reference signal frequency position index on tree layer l, and F l,t is a sounding reference signal position; a receiver configured to receive a receiving a radio resource control signal from another apparatus, the radio resource control signal is a sounding reference signal configuration signalling; and a transmitter configured to transmit an uplink message to the other apparatus including an allocated sounding reference signal based on data in the radio resource control signal.