Transmission parameter adaptation in cooperative signal communication
With respect to cooperative signal communication between a mobile terminal ( 200 ) and a plurality of access nodes ( 100 - 1, 100 - 2 ), a combined signal quality value is calculated on the basis of a first individual signal quality value (Q 1 ) of a communication link between a first access node ( 100 - 1 ), e.g. a serving base station, and the terminal ( 200 ), and a second individual signal quality value (Q 2 ) of a second communication link between a second access node ( 100 - 2 ), e.g. a supporting base station, and the terminal ( 200 ). On the basis of the combined signal quality value, a transmission parameter ( 50 ) for future cooperative transmissions is adapted. The transmission parameter ( 50 ) may be a modulation scheme, a coding scheme, a transmit power, or a resource allocation.
1. A method of cooperative signal communication, comprising:
calculating a signal quality value (Q calc ) based on a first individual signal quality value (Q 1 ) of a first communication link between a first access node and a mobile terminal and based on a second individual signal quality value (Q 2 ) of a second communication link between a second access node and the mobile terminal, wherein the first and second communication links are different; and
setting, based on the Q calc , a transmission parameter for cooperative communication of a signal between the mobile terminal and the first and second access nodes;
wherein the Q 1 the Q 2 , and the Q calc each correspond to:
a signal to interference plus noise ratio (SINR) value,
a received signal strength (RSS) value, or
a channel frequency response function; and
wherein said calculating comprises calculating the Q calc , according to:
Q calc =Max( Q 1 ,Q 2 ) or
Q calc =Q 1 +Q 2 .
2. The method according to claim 1 , wherein the transmission parameter comprises at least one of a modulation scheme and a coding scheme.
3. The method according to claim 1 , wherein the transmission parameter comprises a transmission power.
4. The method according to claim 1 , wherein the transmission parameter comprises a resource allocation.
5. The method according to claim 1 , wherein the method is performed by the first access node and further comprises receiving at least one of the Q 1 and the Q 2 from either the second access node or the mobile terminal.
6. The method according to claim 1 , wherein the method is performed by the first access node and further comprises estimating the Q 2 based on at least one cooperation-specific parameter available to the first access node.
7. The method according to claim 6 , wherein the at least one cooperation-specific parameter is at least one of:
a difference between a path gain of the first communication link and a path gain of the second communication link,
a transmit power of the mobile terminal,
a transmit power of the first access node,
a transmit power of the second access node,
a number of cooperating access nodes for the mobile terminal,
a type of cooperative signal communication, or
a type of receiver algorithm used at the first access node, the second access node, or the mobile terminal.
8. The method according to claim 1 , wherein the Q 1 , the Q 2 , and the Q calc each correspond to a received signal strength value.
9. The method according to claim 8 , wherein said calculating comprises calculating the Q calc , denoted by RSS calc , from the Q 1 , denoted by RSS 1 , and the Q 2 , denoted by RSS 2 , according to:
RSS calc =Max( RSS 1 ,RSS 2 ).
10. The method according to claim 8 , wherein said calculating comprises calculating the Q calc , denoted by RSS calc , from the Q 1 , denoted by RSS 1 , and the Q 2 , denoted by RSS 2 , according to:
RSS calc =RSS 1 +RSS 2 .
11. The method according to claim 1 , wherein the Q 1 , the Q 2 , and the Q calc each correspond to a signal to interference plus noise ratio value.
12. The method according to claim 11 , wherein said calculating comprises calculating the Q calc , denoted by SINR calc , from the Q 1 , denoted by SINR 1 , and the Q 2 , denoted by SINR 2 , according to:
SINR calc =Max( SINR 1 ,SINR 2 ).
13. The method according to claim 11 , wherein said calculating comprises calculating the Q calc , denoted by SINR calc , from the Q 1 , denoted by SINR 1 , and the Q 2 , denoted by SINR 2 , according to:
SINR calc =SINR 1 +SINR 2 .
14. The method according to claim 1 , wherein the Q 1 , the Q 2 , and the Q calc correspond to a channel frequency response function.
15. The method according to claim 14 , wherein said calculating comprises calculating the Q calc , denoted by h calc , from the Q 1 , denoted by h 1 , and the Q 2 , denoted by h 2 , according to:
h calc =Max( h 1 ,h 2 ).
16. The method according to claim 14 , wherein said calculating comprises calculating the Q calc , denoted by h calc , from the Q 1 , denoted by h 1 , and the Q 2 , denoted by h 2 , according to:
h calc =h 1 +h 2 .
17. The method of claim 1 , wherein said setting comprises setting a transmission parameter that governs transmission of the signal by the mobile terminal to the first and second access nodes or transmission of the signal by the first and second access nodes to the mobile terminal.
18. A device comprising one or more interfaces, a processor, and a memory, the memory containing instructions executable by the processor whereby the device is configured to:
calculate a signal quality value (Q calc ) based on a first individual signal quality value (Q 1 ) of a first communication link between a first access node and a mobile terminal and based on a second individual signal quality value (Q 2 ) of a second communication link between a second access node and the mobile terminal, wherein the first and second communication links are different; and
set, based on the Q calc , a transmission parameter for cooperative communication of a signal between the mobile terminal and the first and second access nodes;
wherein the Q 1 the Q 2 , and the Q calc each correspond to:
a signal to interference plus noise ratio (SINR) value,
a received signal strength (RSS) value, or
a channel frequency response function; and
wherein the device is configured to calculate the Q calc , according to:
Q calc =Max( Q 1 ,Q 2 ) or
Q calc =Q 1 +Q 2 .
19. The device according to claim 18 , wherein the device is configured to operate as the first access node.
20. The device according to claim 18 , wherein the transmission parameter comprises at least one of a modulation scheme and a coding scheme.
21. The device according to claim 18 , wherein the transmission parameter comprises a transmission power.
22. The device according to claim 18 , wherein the transmission parameter comprises a resource allocation.
23. The device according to claim 18 , wherein the memory contains instructions executable by the processor whereby the device is configured to receive, via the one or more interfaces, at least one of the Q 1 and the Q 2 from either the second access node or the mobile terminal.
24. The device according to claim 18 , wherein the memory contains instructions executable by the processor whereby the device is further configured to estimate the Q 2 based on at least one cooperation-specific parameter available to the first access node.
25. The device according to claim 18 , wherein the at least one cooperation-specific parameter is at least one of:
a difference between a path gain of the first communication link and a path gain of the second communication link,
a transmit power of the mobile terminal,
a transmit power of the first access node,
a transmit power of the second access node,
a number of cooperating access nodes for the mobile terminal,
a type of cooperative signal communication, or
a type of receiver algorithm used at the first access node, the second access node, or the mobile terminal.
26. The device according to claim 18 , wherein the Q 1 , the Q 2 , and the Q calc each correspond to a received signal strength value.
27. The device according to claim 26 , wherein the processor is configured to calculate the Q calc , denoted by RSS calc , from the Q 1 , denoted by RSS 1 , and the Q 2 , denoted by RSS 2 , according to:
RSS calc =Max( RSS 1 ,RSS 2 ).
28. The device according to claim 26 , wherein the processor is configured to calculate the Q calc , denoted by RSS calc , from the Q 1 , denoted by RSS 1 , and the Q 2 , denoted by RSS 2 , according to:
RSS calc =RSS 1 +RSS 2 .
29. The device according to claim 18 , wherein the Q 1 , the Q 2 , and the Q calc each correspond to a signal to interference plus noise ratio value.
30. The device according to claim 29 , wherein the processor is configured to calculate the Q calc , denoted by SINR calc , from the Q 1 , denoted by SINR 1 , and the Q 2 , denoted by SINR 2 , according to:
SINR calc =Max( SINR 1 ,SINR 2 ).
31. The device according to claim 29 , wherein the processor is configured to calculate the Q calc , denoted by SINR calc , from the Q 1 , denoted by SINR 1 , and the Q 2 , denoted by SINR 2 , according to:
SINR calc =SINR 1 +SINR 2 .
32. The device according to claim 18 , wherein the Q 1 , the Q 2 , and the Q calc correspond to a channel frequency response function.
33. The device according to claim 21 , wherein the processor is configured to calculate the Q calc , denoted by h calc , from the Q 1 , denoted by h 1 , and the Q 2 , denoted by h 2 , according to:
h calc =Max( h 1 ,h 2 ).
34. The device according to claim 32 , wherein the processor is configured to calculate the Q calc , denoted by h calc , from the Q 1 , denoted by h 1 , and the Q 2 , denoted by h 2 , according to:
h calc =h 1 +h 2 .
35. A network system, comprising:
a first access node comprising a wireless interface configured to communicate with a mobile terminal on a first communication link; and
a second access node comprising a wireless interface configured to communicate with the mobile terminal on a second communication link,
wherein the first access node further comprises a processor and a memory, the memory containing instructions executable by the processor whereby the first access node is configured to calculate a signal quality value (Q calc ) based on a first individual signal quality value (Q 1 ) of the first communication link and based on a second individual signal quality value (Q 2 ) of the second communication link, and to set, based on the Q calc , a transmission parameter for cooperative communication of a signal between the mobile terminal and the first and second access nodes;
wherein the Q 1 , and Q 2 , the Q calc each correspond to:
a signal to interference plus noise ratio (SINR) value,
a received signal strength (RSS) value or
a channel frequency response function; and
wherein the first access node is configured to calculate the Q calc according to:
Q calc =Max( Q 1 ,Q 2 ) or
Q calc =Q 1 +Q 2 .
36. A computer program product stored on a non-transitory computer-readable medium and comprising computer program code that, when executed by a processor of a network device, cause the network device to:
calculate a signal quality value (Q calc ) based on a first individual signal quality value (Q 1 ) of a first communication link between a first access node and a mobile terminal and based on a second individual signal quality value (Q 2 ) of a second communication link between a second access node and the mobile terminal; and
set, based on the (Q calc ) calculated signal quality value, a transmission parameter for cooperative communication of a signal between the mobile terminal and the first and second access nodes;
wherein the Q 1 , the Q 2 , and the Q calc each correspond to:
a signal to interference plus noise ratio (SINR) value,
a received signal strength (RSS) value, or
a channel frequency response function; and
wherein the network device is caused to calculate the Q calc according to:
Q calc =Max( Q 1 ,Q 2 ) or
Q calc =Q 1 +Q 2 .