Calibration method for channel simulator
A calibration method for a channel simulator is applied to a large-capacity channel simulator having the interfaces of P base stations and Q terminals so that path loss calibration for P×Q paths is more rapidly and easily performed.
1. A calibration method for a channel simulator that forms channels with respect to all paths between P base stations (P is an integer more than 2) and Q terminals (Q is an integer more than 2), the calibration method comprising:
a base station power calibration step of equally maintaining P analog/digital converter (ADC) powers of base station interface cards of the channel simulator; and
a terminal path loss calibration step of equally maintaining Q digital/analog converter (DAC) powers of terminal interface cards of the channel simulator in a state that one base station subject to the power calibration is connected with the Q terminals,
wherein the calibrated ADC power of each of the base station interface cards (PL ADC ) is defined as follows:
PL
ADC
=
A
ADC
∘
PL
ADC
′
,
wherein
A
ADC
=
(
a
ADC
,
1
...
a
ADC
,
P
)
,
wherein
PL
ADC
′
=
(
PL
ADC
,
1
′
…
PL
ADC
,
P
′
)
,
and
wherein A ADC is a calibration matrix and PL ADC ′ is a measured ADC power matrix, and
wherein the calibrated DAC power of each of the terminal interface cards (PL DAC ) is defined as follows:
PL
DAC
=
A
DAC
∘
PL
DAC
′
,
wherein
A
DAC
=
(
a
DAC
,
1
...
a
DAC
,
Q
)
,
wherein
PL
DAC
′
=
(
PL
DAC
,
1
′
…
PL
DAC
,
Q
′
)
,
and
wherein A DAC is another calibration matrix and PL DAC ′ is a measured DAC power matrix.
2. The calibration method of claim 1 , wherein the base station power calibration step further comprises:
adjusting a gain of an amplifier or an attenuation degree of an attenuator of the base station interface cards after measuring the P ADC powers of the base station interface cards of the channel simulator connected with the P base stations.
3. The calibration method of claim 1 , wherein, in the terminal path loss calibration step, a gain of an amplifier or an attenuation degree of an attenuator of the terminal interface cards in the channel simulator connected with the Q terminals is adjusted using a reference signal received power (RSRP) or a path loss value of each terminal, such that the DAC powers of the terminal interface cards are equally maintained.
4. The calibration method of claim 3 , wherein the RSRP or the path loss value of each terminal is acquired through a diagnostic monitoring (DM) message from each terminal.
5. A calibration method for a channel simulator, in which channels are formed with respect to all paths between P base stations (P is an integer more than 2) and Q terminals (Q is an integer more than 2), the calibration method comprising:
(a) inputting a base station signal having equal power after connecting the P base stations with one terminal;
(b) capturing and measuring analog/digital converter (ADC) powers of base station interface cards connected with the base stations;
(c) performing a calibration such that the ADC powers measured in step (b) are equal to each other;
(d) checking a reference signal received power (RSRP) or a path loss value of each terminal after inputting the base station signal in a state that one base station is connected with the Q terminals; and
(e) performing the calibration such that digital/analog converter (DAC) powers of terminal interface cards connected with the Q terminals are equal to each other using the RSRP and the path loss value,
wherein the calibrated ADC power of each of the base station interface cards (PL ADC ) is defined as follows:
PL
ADC
=
A
ADC
∘
PL
ADC
′
,
wherein
A
ADC
=
(
a
ADC
,
1
...
a
ADC
,
P
)
,
wherein
PL
ADC
′
=
(
PL
ADC
,
1
′
…
PL
ADC
,
P
′
)
,
and
wherein A ADC is a calibration matrix and PL ADC ′ is a measured ADC power matrix, and
wherein the calibrated DAC power of each of the terminal interface cards (PL DAC ) is defined as follows:
PL
DAC
=
A
DAC
∘
PL
DAC
′
,
wherein
A
DAC
=
(
a
DAC
,
1
...
a
DAC
,
Q
)
,
wherein
PL
DAC
′
=
(
PL
DAC
,
1
′
…
PL
DAC
,
Q
′
)
,
and
wherein A DAC is another calibration matrix and PL DAC ′ is a measured DAC power matrix.
6. The calibration method of claim 5 , wherein the calibration in step (c) is performed by:
adjusting a gain of an amplifier or an attenuation degree of an attenuator of the base station interface cards; and
adjusting a gain of an amplifier or an attenuation degree of an attenuator of each terminal interface card.
7. The calibration method of claim 6 , wherein the RSRP and the path loss value of each terminal is acquired through a diagnostic monitoring (DM) message from each terminal.