Scheduling method, radio system, base station, and scheduling module
View Patent ↗There is provided a base station comprising: an estimation unit for estimating a second or higher order statistics for each user terminal in a set of user terminals to be served; an estimation unit for estimating a scheduling metric based on the estimated second or higher order statistics; and a scheduling unit for controlling scheduling based on the estimated scheduling metric.
1. A method comprising:
providing, by a processor, an estimated second or higher order statistics for each user terminal in a set of user terminals to be served;
estimating, by the processor, an ergodic sum capacity of multiple access channels based on the estimated second or higher order statistics;
estimating, by the processor, a scheduling metric based on the estimated ergodic sum capacity; and
controlling, by the processor, scheduling based on the estimated scheduling metric.
2. The method of claim 1 , wherein the estimated second or higher order statistics for each user terminal k has the form of:
E
{
H
k
H
k
H
}
∈
C
M
R
×
M
R
k
,
where H k εC M R ×M T is a channel matrix for a kth user terminal, E denotes a mathematical expectation, and M T and M R are the numbers of transmit and receive antennas.
3. The method of claim 1 , further comprising estimating the ergodic sum capacity of multiple access channels by using a second-order Taylor series of the ergodic sum capacity.
4. The method of claim 1 , wherein the estimated scheduling metric has the form of:
C
S
(
ρ
)
=
ρ
·
E
{
trace
(
∑
i
∈
S
H
i
H
i
H
)
}
-
ρ
2
2
·
E
{
tr
ace
(
(
∑
i
∈
S
H
i
H
i
H
)
2
)
}
where ρ is a tuning constant, E is a mathematical expectation, H i is a channel for user terminal i, and H i H is a Hermitian conjugate of H i .
5. The method of claim 4 , further comprising:
precomputing trace expressions for each user terminal or user terminal pair before estimating the scheduling metric.
6. The method of claim 1 , wherein the estimated scheduling metric has the form of:
C
S
(
ρ
)
=
ρ
·
∑
k
=
1
K
M
T
,
k
trace
(
R
k
)
-
ρ
2
2
·
(
∑
k
=
1
K
∑
l
=
1
K
M
T
,
k
M
T
,
l
trace
(
R
k
R
l
)
+
∑
k
=
1
K
M
T
,
k
trace
(
R
k
)
2
)
where ρ is a tuning constant, M T,k is a number of transmit antennas of a kth user terminal, R k is a receiver side correlation matrix for the kth user terminal, M T,l is a number of transmit antennas of an lth user terminal, and R l is a receiver side correlation matrix for the lth user terminal.
7. The method of claim 1 , further comprising:
using a scheduling algorithm for controlling scheduling based on the estimated scheduling metric.
8. The method of claim 7 , further comprising:
using an opportunistic scheduling algorithm for controlling scheduling.
9. The method of claim 7 , further comprising:
using a round-robin based fair scheduling for controlling scheduling.
10. A system comprising:
a base station;
one or more user terminals communicating with the base station;
an estimation unit for estimating a second or higher order statistics for each user terminal in a set of user terminals to be served;
an estimation unit for estimating an ergodic sum capacity of multiple access channels based on the estimated second or higher order statistics;
an estimation unit for estimating a scheduling metric based on the estimated ergodic sum capacity; and
a scheduling unit for controlling scheduling based on the estimated scheduling metric.
11. The system of claim 10 , wherein the estimated scheduling metric has the form of:
C
S
(
ρ
)
=
ρ
·
E
{
trace
(
∑
i
∈
S
H
i
H
i
H
)
}
-
ρ
2
2
·
E
{
trace
(
(
∑
i
∈
S
H
i
H
i
H
)
2
)
}
where ρ is a tuning constant, E is a mathematical expectation, H i is a channel for user terminal i, and H i H is a Hermitian conjugate of H i .
12. An apparatus, comprising:
a processor;
a memory including a computer program code,
wherein the memory and the computer program code are configured, with the processor, to cause the apparatus, at least, to
estimate a second or higher order statistics for each user terminal in a set of user terminals to be served;
estimate an ergodic sum capacity of multiple access channels based on the estimated second or higher order statistics;
estimate a scheduling metric based on the estimated ergodic sum capacity; and
control scheduling based on the estimated scheduling metric.
13. The apparatus of claim 12 , wherein the estimated second or higher order statistics of each user terminal k has the form of:
E
{
H
k
H
k
H
}
∈
C
M
R
×
M
R
k
,
where H k εC M R ×M T is a channel matrix for a kth user terminal, E denotes a mathematical expectation, and M T and M R are the numbers of transmit and receive antennas.
14. The apparatus of claim 13 , wherein the memory and the computer program code are further configured, with the processor, to cause the apparatus to estimate the ergodic sum capacity of multiple access channels using a second-order Taylor series of the ergodic sum capacity for estimating the ergodic sum capacity.
15. The apparatus of claim 12 , wherein the estimated scheduling metric has the form of:
C
S
(
ρ
)
=
ρ
·
E
{
trace
(
∑
i
∈
S
H
i
H
i
H
)
}
-
ρ
2
2
·
E
{
tr
ace
(
(
∑
i
∈
S
H
i
H
i
H
)
2
)
}
where ρ is a tuning constant, E is a mathematical expectation, H i is a channel for user terminal i, and H i H is a Hermitian conjugate of H i .
16. The apparatus of claim 15 , wherein the memory and the computer program code are further configured, with the processor, to cause the apparatus to precompute trace expressions for each user terminal or user terminal pair before estimating the scheduling metric.
17. The apparatus of claim 12 , wherein the estimated scheduling metric has the form of:
C
S
(
ρ
)
=
ρ
·
∑
k
=
1
K
M
T
,
k
trace
(
R
k
)
-
ρ
2
2
·
(
∑
k
=
1
K
∑
l
=
1
K
M
T
,
k
M
T
,
l
trace
(
R
k
R
l
)
+
∑
k
=
1
K
M
T
,
k
trace
(
R
k
)
2
)
where ρ is a tuning constant, M T,k is a number of transmit antennas of a Kth user terminal, R k is the receiver side correlation matrix for the kth user terminal, M T,l is the number of transmit antennas of an lth user terminal, and R l is a receiver side correlation matrix for the lth user terminal.
18. The apparatus of claim 12 , wherein the memory and the computer program code are further configured, with the processor, to cause the apparatus to use a scheduling algorithm to control scheduling based on the estimated scheduling metric.
19. An apparatus, comprising:
a processor;
a memory including a computer program code,
wherein the memory and the computer program code are configured, with the processor, to cause the apparatus, at least, to
estimate an ergodic sum capacity of multiple access channels based on estimated second or higher order statistics of each user terminal in a set of user terminals to be served;
estimate a scheduling metric based on the estimated ergodic sum capacity; and
provide information for controlling scheduling based on the estimated scheduling metric.
20. The apparatus of claim 19 , wherein the estimated second or higher order statistics of each user terminal k has the form of:
E
{
H
k
H
k
H
}
∈
C
M
R
×
M
R
k
,
where H k εC M R ×M T is a channel matrix for the kth user terminal, E denotes a mathematical expectation, and M T and M R are the numbers of transmit and receive antennas.
21. The apparatus of claim 19 , wherein the memory and the computer program code are further configured, with the processor, to cause the apparatus to estimate the ergodic sum capacity of multiple access channels using a second-order Taylor series of the ergodic sum capacity for estimating the ergodic sum capacity.
22. The apparatus of claim 19 , wherein the estimated scheduling metric has the form of:
C
S
(
ρ
)
=
ρ
·
E
{
trace
(
∑
i
∈
S
H
i
H
i
H
)
}
-
ρ
2
2
·
E
{
tr
ace
(
(
∑
i
∈
S
H
i
H
i
H
)
2
)
}
where ρ is a tuning constant, E is a mathematical expectation, H i is a channel for user terminal i, and H i H is a Hermitian conjugate of H i .
23. The apparatus of claim 22 , wherein the memory and the computer program code are further configured, with the processor, to cause the apparatus to pre-compute trace expressions for each user terminal or user terminal pair before estimating of the scheduling metric.
24. The apparatus of claim 19 , wherein the estimated scheduling metric has the form of:
C
S
(
ρ
)
=
ρ
·
∑
k
=
1
K
M
T
,
k
trace
(
R
k
)
-
ρ
2
2
·
(
∑
k
=
1
K
∑
l
=
1
K
M
T
,
k
M
T
,
l
trace
(
R
k
R
l
)
+
∑
k
=
1
K
M
T
,
k
trace
(
R
k
)
2
)
where ρ is a tuning constant, M T,k is a number of transmit antennas of a kth user terminal, R k is a receiver side correlation matrix for the kth user terminal, M T,l is a number of transmit antennas of an lth user terminal, and R i is the receiver side correlation matrix for the lth user terminal.
25. The apparatus of claim 19 , wherein the memory and the computer program code are further configured, with the processor, to cause the apparatus to use a scheduling algorithm to control scheduling based on the estimated scheduling metric.
26. The apparatus of claim 25 , wherein the memory and the computer program code are further configured, with the processor, to cause the apparatus to use an opportunistic scheduling algorithm to control scheduling.
27. The apparatus of claim 25 , wherein the memory and the computer program code are further configured, with the processor, to cause the apparatus to use a round-robin based fair scheduling to control scheduling.
28. A scheduling module for a radio system, comprising:
estimation means for estimating an ergodic sum capacity of multiple access channels based on estimated second or higher order statistics of each user terminal in a set of user terminals to be served;
estimation means for estimating a scheduling metric based on the estimated ergodic sum capacity; and
processing means for providing information for controlling scheduling based on the estimated scheduling metric.
29. The scheduling module of claim 28 , wherein the estimated scheduling metric has the form of:
C
S
(
ρ
)
=
ρ
·
E
{
trace
(
∑
i
∈
S
H
i
H
i
H
)
}
-
ρ
2
2
·
E
{
tr
ace
(
(
∑
i
∈
S
H
i
H
i
H
)
2
)
}
where ρ is a tuning constant, E is a mathematical expectation, H i is a channel for user terminal i, and H i H is a Hermitian conjugate of H i .
30. A computer program on a computer-readable medium having computer executable components for executing a computer process for scheduling, the process comprising:
providing an estimated second or higher order statistics for each user terminal in a set of user terminals to be served;
estimating an ergodic sum capacity of multiple access channels based on estimated second or higher order statistics;
estimating a scheduling metric based on the estimated ergodic sum capacity; and
controlling scheduling based on the estimated scheduling metric.
31. The computer program of claim 30 , wherein computer-readable medium comprises at least one of the following media: a program storage medium, a record medium, a computer readable memory, a computer readable software distribution package, and a computer readable compressed software package.