Wireless communication apparatus and method

A base station with multiple transmit antennae for communicating with a mobile terminal having at least a single receive antenna over physical channels h1(k), h2(k), the base station comprising:

• a space-time encoder having an input of a signal to be transmitted s(n) and at least two outputs each producing a separate signal s1(n),s2(n);
• at least two zero-forcing pre-equalisers, each fed by a respective output signal s1(n),s2(n) and having a respective function g1(k), g2(k) to produce an output signal x1(n), x2(n);
• and
• at least two transmit antennae, each being fed by the output signal x1(n),x2(n) of a respective one of the pre-equalisers, wherein the functions g1(k),g2(k) of the zero-forcing pre-equalisers are selected such that the channel responses g1(k)*h1(k), g2(k)*h2(k) of the respective physical channels h1(k), h2(k) are flat fading channels.

A method of achieving combined beamforming and transmit diversity for frequency selective fading channels in a communication system having a base station with multiple transmit antennae and a mobile terminal with at least a single receive antenna, the method comprising the steps of:

• providing a signal to be transmitted S(n;k);
• space-time encoding the signal S(n;k) to produce at least two separate signals S1(n;k),S2(n;k), each on a respective output;
• feeding each output signal S1(n;k),S2(n;k) to a transmit processor to produce an output signal X1(n;k), X2(n;k);
• applying respective selected transmit beamforming weights to each output signal X1(n;k), X2(n;k);
• feeding the respective weighted signals to a signal combiner to perform a summing function of the signals and produce a signal X(n;k) for transmission;
• feeding the summed signal X(n;k) to each of the multiple transmit antennae for transmission;
• transmitting the signals X(n;k) over physical channel h(n;k);
• receiving the received signal Y(n;k) at at least a single receive antenna;
• feeding the received signal Y(n;k) to a receive processor to produce an output signal;
• and
• space-time decoding the received signal.

A base station with multiple transmit antennae for communicating with a mobile terminal having at least a single receive antenna over physical channel h(k), the base station comprising:

• a space-time encoder having an input of a signal to be transmitted and at least two outputs each producing a separate signal;
• at least two transmit processors each receiving one of the outputs from a respective space-time encoder;
• at least two transmit beamformers each receiving an output from a respective transmit processor and applying a transmit beamforming weight thereto;
• a signal combiner receiving signals from the beamformers and operable to perform a summing function of the signals from the beamformers and produce a signal for transmission by the multiple transmit antennae.

A method of achieving combined beamforming and transmit diversity for frequency selective fading channels in a communication system having a base station with multiple transmit antennae and a mobile terminal with at least a single receive antenna, the method comprising the steps of:

• providing a signal to be transmitted s(n);
• space-time encoding a signal to be transmitted s(n) to produce at least two separate signals s1(n),s2(n), each on a respective output;
• delaying one of the space-time encoded output signals by Δτ;
• applying respective selected transmit beamforming weights to the delayed and undelayed signals;
• feeding the respective weighted signals to a signal combiner to perform a summing function of the signals and produce a signal for transmission;
• feeding the summed signal to each of the multiple transmit antennae for transmission;
• transmitting the summed signals over the physical channel h(k);
• receiving the major components of the transmitted signals at at least a single receive antenna at substantially the same time;
• and
• space-time decoding the received signal.