Method for measuring interference power in time-slot CDMA system
The present invention relates to a method for measuring interference power in a time slot CDMA system, The method includes: performing channel estimation for received signals with channel estimation codes, to obtain the original channel response estimation results h i , i=1 . . . P; predetermining a threshold of number of taps W 1 , and selecting the channel response estimation results for W 1 taps with less power from the original channel response estimation results h i for W 1 as the roughly estimated result of the interference power; performing threshold processing on the original channel response estimation results by post-processing against signal-to-noise ratio threshold, by using the roughly estimated result of the interference power and the predetermined signal-to-noise ratio threshold, before processing compensating the possible error generated from rough estimation of the interference power and performing threshold processing with the compensated power threshold, so as to ultimately obtain an accurate measured result of the interference power.
1. A method for measuring interference power in a time slot code division multiple access system, comprising:
A. performing channel estimation for received signals with channel estimation codes, to obtain channel response results of all possible user terminals in the current cell, i.e., the original channel response estimation results h i , i=1 . . . P, wherein P is the total length of channel estimation windows;
B. predetermining a threshold of number of taps W 1 , and selecting channel response estimation results corresponding to W 1 taps with less power from the original channel response estimation results h i according to the threshold of number of taps W 1 as a roughly estimated result of the interference power; and
C. performing threshold processing on the original channel response estimation results with a signal-to-noise ratio threshold post-processing method by using the roughly estimated result of the interference power and a predetermined signal-to-noise ratio threshold, to obtain an accurate measured result of the interference power;
wherein said threshold of number of taps W 1 is in a range of 50 to 90.
2. A method for measuring interference power in a time slot code division multiple access system according to claim 1 , wherein said threshold of number of taps W 1 is less than the number of taps of the actual interference responses available.
3. A method for measuring interference power in a time slot code division multiple access system according to claim 1 , wherein said threshold of number of taps W 1 is 80.
4. A method for measuring interference power in a time slot code division multiple access system according to claim 1 , wherein in step B, the roughly estimated result of the interference power σ n1 2 is obtained with equation
σ
n
1
2
=
P
D
·
W
∑
i
=
1
P
h
_
i
′
2
,
wherein h′ i is the channel response estimation results for W 1 taps, and D is the noise degradation factor of the corresponding channel estimation code.
5. A method for measuring interference power in a time slot code division multiple access system according to claim 1 , wherein step C of performing threshold processing on the original channel response estimation results with the signal-to-noise ratio threshold post-processing method further comprises:
C1. obtaining a compensated threshold of the interference power Γ CHE with equation
Γ
CHE
=
σ
n
1
2
ɛ
CHE
P
β
according to the predetermined signal-to-noise ratio threshold ε CHE , the compensation value β, and the roughly estimated result of the interference power σ n1 2 ;
C2. selecting channel response estimation results corresponding to W 2 taps with the power lower than the threshold of the interference power Γ CHE from the original channel response estimation results as the interference response results h″ i of the signal-to-noise ratio threshold post-processing;
C3. obtaining the accurate measured value of the interference power with equation
σ
n
2
=
P
D
·
W
2
∑
i
=
1
P
h
_
i
″
2
,
wherein D is the noise degradation factor of the corresponding channel estimation code.
6. A method for measuring interference power in a time slot code division multiple access system according to claim 5 , wherein said signal-to-noise ratio threshold ε CHE is in a range of 3 to 5, and wherein said compensation value β is provided for the lower roughly estimated result of the interference power and is in a range of 0.30 to 0.60.
7. A method for measuring interference power in a time slot code division multiple access system according to claim 6 , wherein said signal-to-noise ratio threshold ε CHE is 4, and said compensation value β is 0.41.