Method for inter-cell interference mitigation for a mobile communication system
View Patent ↗A method for reducing inter-cell interference (ICI) in a mobile communication system controls transmission signal power of an uplink signal from a terminal based on signal power measurement for a signal received from a base station of a neighboring cell. A terminal receives a signal from a base station of a neighboring cell via a wireless channel, measures a channel response against a threshold value across an applicable frequency band by using the received signal, determines a transmission signal power for each frequency band used for data transmission based on the measured channel response, and transmits data to a home cell base station according to the transmission signal power for each frequency band. The terminal may measure a channel response based on signals received from multiple base stations in multiple neighboring cells, and may also evaluate signal power of a signal transmitted from the home cell.
1. A method for managing uplink channel resources in a mobile communication terminal located in a first cell, comprising:
measuring a received signal power of a first downlink channel signal for a plurality of frequency bands, the first downlink channel signal transmitted from a base station of a second cell; and
determining a transmission signal power of an uplink channel signal for each frequency band of the plurality of frequency bands based on the received signal power,
wherein the plurality of frequency bands comprises a first frequency band and a second frequency band, and transmission signal power for the first frequency band is selected to be lower than transmission signal power for the second frequency band based on the received signal power, and
wherein determining the transmission signal power further comprises:
comparing the received signal power with a threshold value that is uniform across the frequency bands; and
excluding the first frequency band from the uplink channel signal or adjustinq power of the first frequency band downward if the first frequency band has a transmission signal power that is greater than the threshold value.
2. The method of claim 1 , wherein determining the transmission signal power comprises adjusting the transmission signal power for the first frequency band having a received signal power that is greater than the threshold value to a reduced transmission signal power that is less than or equal to the threshold value.
3. The method of claim 1 , wherein determining the transmission signal power comprises excluding the first frequency band from the uplink channel signal by setting the transmission signal power for the first frequency band to zero watts if the first frequency band has a received signal power that is greater than a threshold value.
4. The method of claim 1 , further comprising:
measuring a received signal power of a second downlink channel signal for the frequency bands, the second downlink channel signal transmitted from a base station in the first cell,
wherein determining the transmission signal power further comprises referring to the received signal power of the second downlink channel signal.
5. The method of claim 4 , wherein determining the transmission signal power further comprises:
comparing a ratio of the received signal power of the second downlink channel signal to the received signal power of the first downlink channel signal with the threshold ratio for each frequency band; and
adjusting the transmission signal power based on the comparison if the ratio exceeds the threshold ratio.
6. The method of claim 4 , wherein determining the transmission signal power comprises:
arranging the plurality of frequency bands based on a ratio of the first received signal power to the second received signal power; and
selecting the transmission signal power for each frequency band based on the arranged order.
7. The method of claim 4 , further comprising:
comparing the received signal power of the second downlink channel signal with the threshold value; and
selecting each frequency band for the uplink channel signal if the received signal power of the second downlink channel signal is less than or equal to the threshold value in each frequency band.
8. The method of claim 1 , wherein the uplink channel signal and the first downlink channel signal transmit via a same plurality of frequency bands.
9. The method of claim 1 , wherein the first downlink channel signal comprises a common pilot channel signal.
10. The method of claim 1 , wherein the first downlink channel signal and the uplink channel signal transmit data according to an orthogonal frequency division multiplexing (OFDM) scheme.
11. The method of claim 1 , wherein the first downlink channel signal and the uplink channel signal transmit the data according to a Time Division Duplexing (TDD) scheme.
12. A method for transmitting data in a mobile communication system, comprising:
receiving a pilot signal from a first base station via a wireless channel;
measuring a channel response of the wireless channel by using the pilot signal;
determining a transmission signal power for each of a plurality of frequency bands used for data transmission based on the channel response, wherein the plurality of frequency bands comprises first frequency bands and second frequency bands, and transmission signal power for the first frequency bands is selected to be lower than transmission signal power for the second frequency bands based on the channel response; and
transmitting data to a second base station based on the transmission signal power for each frequency band,
wherein the channel response comprises a signal strength of the pilot signal for each frequency band, and
determining the transmission signal power further comprises:
comparing the signal strength for each frequency band with a threshold value; and
excluding the first frequency bands from the frequency bands for transmitting data by setting the transmission signal power for the first frequency bands to zero watts if the signal strength for the first frequency bands is greater than the threshold value.
13. The method of claim 12 , wherein the channel response comprises a signal-to-interference plus noise ratio (SINR) or a signal gain measured for each frequency band of the pilot signal.
14. The method of claim 12 , wherein determining the transmission signal power comprises:
dividing the frequency bands into the first frequency bands with a good channel response and the second frequency bands with a poor channel response; and
selecting a transmission signal power of the first frequency bands that is less than a transmission signal power of the second frequency bands.
15. The method of claim 12 , wherein the threshold value is uniform for the frequency bands.
16. The method of claim 12 , wherein the mobile communication system comprises a wireless system using an OFDM scheme.
17. The method of claim 12 , wherein transmitting data comprises transmitting data in a diversity mode with frequency hopping among the frequency bands.
18. The method of claim 12 , further comprising:
receiving a plurality of pilot signals from a plurality of base stations respectively arranged in a plurality of neighboring cells,
wherein the channel response is measured with respect to the plurality of pilot signals.
19. A computer-readable recording medium storing a program for implementing the method of claim 1 ,
wherein the computer-readable recording medium comprises a hard disk, a floppy disk, a magnetic tape, optical media, magneto-optical media, read-only memory (ROM), random access memory (RAM), flash memory, or hardware configured to store and perform program instructions.
20. A computer-readable recording medium storing a program for implementing the method of claim 12 ,
wherein the computer-readable recording medium comprises a hard disk, a floppy disk, a magnetic tape, optical media, magneto-optical media, read-only memory (ROM), random access memory (RAM), flash memory, or hardware configured to store and perform program instructions.