Patent ID: 7990942
Filing Date: 2011-08-02
Classification: H04B

Abstract:
1. A base station for communicating with a wireless terminal by specifying a radiation pattern for each channel in a time-division manner, comprising: an array antenna for transmitting and receiving a pilot signal and data using a radiation pattern that is specified from among radiation patterns that include one of an omnidirectional manner and a directional manner according to a sector and a beam pattern; a scheduler for specifying the radiation pattern and a direction of the beam pattern; a reverse-link beam controller for receiving a first signal or data from the wireless terminal via the array antenna; a demodulator for demodulating the first signal or data received by the reverse-link beam controller; a modulator for modulating a second signal or data to the wireless terminal; and a forward-link beam controller for transmitting the modulated second signal or data to the wireless terminal via the array antenna, wherein the scheduler outputs to the forward-link beam controller radiation pattern information for transmitting the pilot signal in a direction in which the wireless terminal is located, using the beam pattern; transmitting a first slot that includes a common pilot channel transmitted to the wireless terminal in an omnidirectional manner or in a directional manner according to a sector, an individual pilot channel transmitted using the beam pattern among a plurality of beam patterns, and a data channel for transmitting data to the wireless terminal using the beam pattern, the forward-link beam controller performs control, including synchronization, using the common pilot channel of the first slot and, using the individual pilot channel of the first slot, the forward-link beam controller transmits, a pilot signal using the radiation pattern including the beam pattern in the direction in which the wireless terminal is located, based on the radiation pattern information from the scheduler; the reverse-link beam controller receives, via the array antenna, a transmitted signal for requesting data rate determined by the wireless terminal located in the direction according to the reception quality of the pilot signal; the demodulator demodulates the received signal to obtain the requested data rate; a predetermined period after the first slot, the scheduler re-outputs the radiation pattern information to the forward-link beam controller and outputs to the modulator the data to be transmitted to the wireless terminal and the data rate obtained in the demodulator; the modulator modulates the data to be transmitted to the wireless terminal according to the data rate from the scheduler, using a data channel of a second slot which occurs a predetermined number of slots after the first slot, and outputs the modulated data to the forward-link beam controller; and the forward-link beam controller transmits to the wireless terminal the data in the data channel of the second slot, which is modulated by the modulator, using the radiation pattern including the beam pattern in the same direction as the direction in which the pilot signal is transmitted, based on the radiation pattern information from the scheduler.