Abstract
A differential detection scheme for space-time spreading with two transmit antennas is proposed. The scheme does not require channel state information at either the transmitter or the receiver. With segmentation and preamble symbols padded at the transmitter, the receiver recovers the information using differential detection. Both phase-shift keying (PSK) and quadrature amplitude modulation (QAM) signals are considered. The proposed scheme achieves two-level transmit diversity gain with low complexity and saves the use of channel estimation, while having about 3 dB performance loss as compared to the coherent detection scheme. When multiple receive antennas exist, additional receive diversity gain can be achieved along with the transmit diversity gain. The scheme works fine under block-fading channel as well as slow Rayleigh fading channel, which is a popular scenario for high-rate data communications. The system performance for different segment sizes, channel fading speeds, modulation methods, and numbers of receive antennas is studied through simulations.
Highlights
Receive diversity has been well known as one powerful technique to mitigate the effect of fading and shadowing for high-rate data transmission over wireless hostile channels
It is intuitive to consider transferring from receive diversity at the mobile station (MS) to transmit diversity at the base station (BS), which can properly balance the problems of electronics, power consumption, size of antenna arrays, and so forth
We further study the impact on the performance of the proposed scheme by the segmentation size, fading speed of the channel, modulation methods, and the number of receive antennas
Summary
Receive diversity has been well known as one powerful technique to mitigate the effect of fading and shadowing for high-rate data transmission over wireless hostile channels. Inspired by the space-time block codes [3, 9], Hochwald and his colleagues proposed a transmit diversity scheme known as space-time spreading (STS) [11] for the downlink wideband direct-sequence (DS) code-division multipleaccess (CDMA) systems, which achieves full transmit diversity with the use of multiple transmit antennas. We consider the case that no given knowledge on channel is available at either the transmitter or the receiver, and propose a differential detection scheme for STS with two transmit antennas and multiple receive antennas. C1 and c2 are made orthogonal to each other and their effective spreading factors are 2 × SF With this construction, no additional resources of spreading codes are required for two transmit antennas.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
