US2009170497A1PendingUtilityA1
Probabilistic interference mitigation for wireless cellular networks
Est. expiryDec 28, 2027(~1.4 yrs left)· nominal 20-yr term from priority
H04W 72/541
50
PatentIndex Score
0
Cited by
0
References
0
Claims
Abstract
An interference mitigation system randomizes transmissions to cell-edge users by carefully controlling the probability of transmission to these users, thereby creating a virtual fractional frequency system that does not require extensive frequency management and coordination across the network. In some embodiments, the interference mitigation system identifies severely interfered links and reduces the probability of transmission on these links, with the result being a reduced probability of interference.
Claims
exact text as granted — not AI-modified1 . A system, comprising:
a base station comprising a medium access controller, the medium access controller comprising transmission randomization capability; a subscriber station comprising co-channel interference avoidance, the subscriber to notify the base station when interference exceeds a threshold;
wherein transmissions to the subscriber station are randomized based on a channel threshold for the subscriber station.
2 . The system of claim 1 , further comprising:
a second base station comprising a second medium access controller the second medium access controller comprising transmission randomization capability, the base station to notify the second base station when interference exceeds the threshold;
wherein transmissions by the second base station to the subscriber station are randomized based on the channel threshold.
3 . The system of claim 2 , wherein the transmissions to the subscriber station are randomized after receiving notification from both base stations.
4 . The system of claim 2 , the base station and the second base station further comprising physical layer optimization, wherein the base stations determine power allocation and rate parameters for a link between the base station and the subscriber station.
5 . The system of claim 4 , wherein the power allocation is given by:
if
P
m
<
P
_
1
-
F
(
H
_
(
i
,
j
)
k
*
)
,
P
(
i
,
j
)
k
*
(
h
)
=
P
m
for
h
≥
H
_
(
i
,
j
)
k
*
,
otherwise
,
P
(
i
,
j
)
k
*
(
h
)
=
{
P
m
υ
*
<
R
(
hP
m
n
o
W
)
h
n
o
W
0
υ
*
≥
R
(
hP
m
n
o
W
)
h
n
o
W
,
R
′
-
1
(
υ
*
n
o
W
h
)
n
o
W
h
otherwise
where h≧ H (i,j) k *. R′ −1 ( ) is an inverse function of R′( ), and υ*≧0 is uniquely given by
∫
H
_
(
i
,
k
)
k
∞
P
(
i
,
j
)
k
*
(
h
)
f
(
h
)
h
=
P
_
.
6 . The system of claim 1 , wherein the threshold is determined using an optimization equation:
H
_
*
=
arg
max
X
_
∑
∀
(
i
,
j
)
k
ln
(
p
(
i
,
j
)
k
∏
l
∈
N
j
(
1
-
p
l
)
)
,
where (i,j) k is the link between the i th base station and the j th subscriber on the k th channel, and p(i,j) k is the probability of transmission on link (i,j) k , and p l is the probability of transmission by the l th interfering base station.
7 . A method, comprising:
determining a channel threshold for a link between a base station and a subscriber; and setting a probability of transmission for the link based on the channel threshold.
8 . The method of claim 7 , further comprising:
receiving an indication of interference from the subscriber by the base station;
wherein the subscriber interference indication causes the base station to determine the channel threshold.
9 . The method of claim 7 , further comprising:
determining a location of the subscriber;
wherein the base station determines the channel threshold when the location exceeds a predetermined distance from a cell center in which the base station resides.
10 . The method of claim 7 , further comprising:
identifying interference by the subscriber, the subscriber being part of a wireless neighborhood comprising base stations and subscribers.
11 . The method of claim 10 , further comprising:
comparing an interference-to-carrier ratio of the link to a threshold; and not reporting interference to the base station if the threshold is not exceeded.
12 . The method of claim 11 , further comprising:
reporting the interference to the base station if the threshold is exceeded.
13 . The method of claim 12 , further comprising:
reporting the interference to other base stations in the wireless neighborhood;
wherein each base station communicates with the subscriber according to the probability of transmission.
14 . The method of claim 13 , further comprising:
obtaining the threshold using an optimization equation.
15 . The method of claim 14 , obtaining the threshold using an optimization equation further comprising:
using optimization equation
H
_
*
=
arg
max
H
_
∑
∀
(
i
,
j
)
k
ln
(
p
(
i
,
j
)
k
∏
l
∈
N
j
(
1
-
p
l
)
)
,
where (i,j) k is the link between the i th base station and the j th subscriber on the k th channel, and p(i,j) k is the probability of transmission on link (i,j) k , and p l is the probability of transmission by the l th interfering base station.
16 . A method, comprising:
identifying interference by a subscriber, the subscriber being part of a wireless neighborhood comprising base stations and subscribers, wherein the subscriber reports the interference to a base station; determining a channel threshold for a link between the base station and the subscriber; and setting a probability of transmission for the link based on the channel threshold.
17 . The method of claim 16 , further comprising:
comparing an interference-to-carrier ratio of the link to a threshold; and not reporting interference to the base station if the threshold is not exceeded.
18 . The method of claim 17 , further comprising:
reporting the interference to the base station if the threshold is exceeded.
19 . The method of claim 18 , further comprising:
using optimization equation
H
_
*
=
arg
max
H
_
∑
∀
(
i
,
j
)
k
ln
(
p
(
i
,
j
)
k
∏
l
∈
N
j
(
1
-
p
l
)
)
,
where (i,j) k is the link between the i th base station and the j th subscriber on the k th channel, and p(i,j) k is the probability of transmission on link (i,j) k , and p l is the probability of transmission by the l th interfering base station.Join the waitlist — get patent alerts
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