A wide variety of wireless communication techniques can be used to transmit and receive data between a transceiver, e.g., a base station, and a terminal, e.g., a mobile phone or station. Exemplary network types include time division multiplexing (TDM), frequency division (FDM), and code division. Each of these systems has concomitant advantages and disadvantages. For example, single carrier systems, such as TDM and FDM, suffer problems from signal delay spread, which can degrade system performance and impact the overall efficiency.
Simulcasting techniques for wireless communication are well known in the art. In general, a plurality of transmitting stations each simultaneously transmits a given signal from the same frequency (FDM) and/or time (TDM) slots. Users within areas covered by the simulcasting transmitters receive the simulcast signals. When near cell boundaries, a user will receive a simulcast signal from each base station serving a neighboring cell. Simulcasting enhances coverage and spectrum efficiency as compared to systems that broadcast a given signal on different channels for each user requesting the signal when the same signal is requested by multiple users.
However, simulcasting systems suffer some of the same disadvantages as non-simulcasting technologies. For example, single carrier simulcasting systems typically suffer problems from signal delay spread and co-channel interference and limited frequency re-use for non-simulcast signals. Furthermore, delay spread can be even longer in simulcast systems since the signal is transmitted by many base stations which may be located at a range of distances from a mobile receiver.
Multiple-input multiple-output (MIMO) is another technique that increases spectral efficiency. In MIMO systems, multiple transmit antennas transmit different signals, all of which are separated and detected by multiple receive antennas. In general, with M receive antennas, up to M signals, either MIMO or co-channel interfering signals, or a combination thereof, can be separated and detected and/or suppressed at the receiver. Thus, when co-channel interference is not present, the use of N transmit and M receive antennas results in an increase in link capacity of the minimum of N and M, i.e., if N less than or equal to M, an N-fold increase in capacity, theoretically without any increase in total transmit power. However, N-fold MIMO increases the number of co-channel interferers N-fold, requiring an N-fold increase in the number of receive antennas to suppress the co-channel interference. Alternatively, for a given number of receive antennas, the degree of MIMO permitted in a system is reduced with aggressive frequency re-use, if MIMO is permitted at all.
It would, therefore, be desirable to provide a wireless simulcasting communication system that overcomes the aforesaid and other disadvantages.