Spread-spectrum transmitter and receiver providing suppressed interference between high-speed and low-speed communication users

A receiver for being provided in a mobile station of a low-speed communication user conducting communication with a base station which includes a first antenna having a wide directivity and a second antenna having a directivity narrower than that of the first antenna, which conducts communication with said mobile station of said low-speed communication user and a mobile station of a high-speed communication user according to a spread spectrum system and which, when both said mobile station of said low-speed communication user and said mobile station of said high-speed communication user are located within an area to receive a signal from said second antenna, transmits (i) first transmission signals to the mobile station of the low-speed communication user from said first antenna and said second antenna and (ii) second transmission signals, different from said first transmission signals, to said mobile station of said high-speed communication user from the second antenna, while the first transmission signal transmitted from the first antenna is delayed by a predetermined period of time relative to the first transmission signal transmitted from the second antenna, said receiver comprising:

• receiving means for receiving the first transmission signals which are sent from the first and second antennas of the base station, respectively;
• first demodulating means for despreading the received first transmission signal from said second antenna using a despreading code;
• delaying means for delaying the despreading code by the predetermined period of time;
• and
• second demodulating means for despreading the received first transmission signal from said first antenna using the delayed despreading code.

A receiver for being provided in a mobile station of a low-speed communication user conducting communication with a base station which includes a first antenna having a wide directivity and a second antenna having a directivity narrower than that of the first antenna, which conducts communication with said mobile station of said low-speed communication user and a mobile station of a high-speed communication user according to a spread spectrum system, and which, when both said mobile station of said low-speed communication user and said mobile station of said high-speed communication user are located within an area to receive a signal from said second antenna, transmits (i) first transmission signals to the mobile station of the low-speed communication user from said first antenna and said second antenna and (ii) second transmission signals, different from said first transmission signals, to said mobile station of said high-speed communication user from the second antenna, while the first transmission signal transmitted from the first antenna is delayed by a predetermined period of time relative to the first transmission signal transmitted from the second antenna, said receiver comprising:

• an antenna for receiving the first transmission signals which are sent from the first and second antennas of the base station, respectively;
• first despreading means for despreading the received first transmission signal from said second antenna using a despreading code to be converted into a first despread signal;
• first delaying means for delaying the first despread signal by the predetermined period of time;
• second delaying means for delaying the despreading code by the predetermined period of time;
• second despreading means for despreading the received first transmission signal from said first antenna using the delayed despreading code obtained from the second delaying means to be converted into a second despread signal;
• and
• demodulating means for combining the first despread signal delayed in the first delaying means with the second despread signal and thereby demodulating the first transmission signal.