Radio communication terminal and radio signal receiving method
View Patent ↗When a radio communication terminal including an AGC receiver starts, a set gain of the AGC receiver is switched in a short updating period. At this time, the terminal switches among antennas, and calculates and stores a received power of a received radio signal through each antennal. This calculation is performed a predetermined number of times for each antenna. After that, the terminal compares the calculated received powers of the radio signal through each antenna, and fixedly uses, as a receiving antenna, one of the antennas which receives a signal with the largest power.
1. A radio communication terminal comprising:
a plurality of antennas;
an antenna switching unit for switching an antenna to another;
a receiver for amplifying a received signal under automatic gain control;
a power calculator for calculating received signal power based on a gain and output of said receiver;
a memory for storing the calculated power values; and
a power determining unit for selecting an antenna which receives the largest signal power; and
wherein the received signal is received during a high speed operation when the receiver starts.
2. The radio communication terminal according to claim 1 , further comprising a gain calculator for calculating a gain based on an output from the receiver.
3. The radio communication terminal according to claim 2 , further comprising a gain controller,
wherein the gain calculator outputs the gain to the power calculator and the gain controller.
4. The radio communication terminal according to claim 2 , further comprising an average power calculator for calculating an average power of a plurality of signals output from the receiver.
5. The radio communication terminal according to claim 4 , wherein the average power calculator outputs the average power to the gain calculator and the power calculator.
6. The radio communication terminal according to claim 1 , wherein a power control unit controls the antenna switching unit to switch the antenna.
7. The radio communication terminal according to claim 1 , wherein the power determining unit compares the power values stored in the memory for each of the antennas.
8. The radio communication terminal according to claim 1 , wherein, based on a gain and output of the receiver, the power calculator calculates the power of a signal received through each of the antennas.
9. The radio communication terminal according to claim 1 , wherein the receiver employs direct conversion method.
10. A radio signal receiving method comprising the steps of:
receiving a radio signal through one of a plurality of antennas by a receiver operating under automatic gain control;
calculating the power of the received radio signal based on a gain and output of said receiver;
switching the antenna to another;
storing the calculated power for each of the antennas in a memory;
calculating a gain based on the output of said receiver and setting the calculated gain in said receiver; and
selecting an antenna which receives an signal with the largest power.
11. The radio signal receiving method according to claim 10 , further comprising a step of calculating an average power of a plurality of signals output from the receiver.
12. The radio signal receiving method according to claim 11 , wherein calculation of the average power is performed within a period in which a predetermined gain is retained in the receiver and after the receiver stabilizes.
13. The radio signal receiving method according to claim 11 , wherein, when calculation of the average power is initially executed, the calculation is performed within a period in which a predetermined gain is retained in the receiver.
14. The radio signal receiving method according to claim 11 , wherein setting of the calculated gain in the receiver is performed after calculation of the next average power ends.
15. The radio signal receiving method according to claim 11 , wherein switching of an antenna to another is performed after calculation of the average power ends.
16. The radio signal receiving method according to claim 10 , wherein each of the steps is executed during a high speed operation of said receiver when said receiver starts.
17. The radio signal receiving method according to claim 10 , wherein the power of the radio signal is calculated a number of times for each of the antennas.
18. The radio signal receiving method according to claim 17 , wherein the calculated powers are added up.