Communication terminal, base station system, and method of controlling transmission power
View Patent ↗An antenna 20 receives signals orthogonal to each other transmitted from different antennas of a base station, and a despreader 202 and a spreader 203 despread the respective received signals using the same spreading code used in the base station, a demodulator 204 and a demodulator 205 demodulate the despread signals, a reception power measuring section 207 and a reception power measuring section 208 measure reception power from the demodulation results, a reception power combiner 209 combines measured reception power, and a transmission power controller 212 controls transmission power based on combined reception power. This makes it possible to perform open loop transmission power control at high speed and with high accuracy even when a fading variation is small.
1. A communication terminal apparatus that receives a plurality of transmission signals that are transmitted in parallel from different antennas of a base station apparatus, said plurality of transmission signals comprising data spread by respective spreading code sequences, and being multiplexed with respective midambles, said communication terminal apparatus comprising:
a plurality of despreaders that despread data parts of the plurality of transmission signals by said respective spreading code sequences;
a plurality of demodulators that demodulate signals despread in the despreaders;
a data configurer that restores a plurality of data demodulated in the demodulators in form prior to division, and obtains received data;
a plurality of measurers that measure and average respective reception powers of midamble parts of received transmission signals;
a combiner that weights a plurality of reception power average values measured at said plurality of measurers, combines weighted reception power average values and obtains a combined reception power; and
a transmission power controller that performs open loop transmission power control by a value obtained by adding interference power at the base station apparatus and a predetermined constant to a propagation loss which is a difference between transmission power of the base station apparatus and the combined reception power.
2. A radio communication method in a communication terminal apparatus that receives a plurality of transmission signals that are transmitted in parallel from different antennas of a base station apparatus, said plurality of transmission signals comprising data spread by respective spreading code sequences, and being multiplexed with respective midambles, said radio communication method comprising the steps of:
performing despreading processing of data parts of the plurality of transmission signals by said respective spreading code sequences;
demodulating a plurality of despread signals;
restoring a plurality of demodulated signals in form prior to division, and obtaining received data;
measuring and averaging respective reception power of midamble parts of received transmission signals;
weighting a plurality of measured reception power average values, combining weighted reception power average values and obtaining a combined reception power; and
performing open loop transmission power control by a value obtained by adding interference power at the base station apparatus and a predetermined constant to a propagation loss which is a difference between transmission power of the base station apparatus and the combined reception power.