Cyclic delay diversity

About: Cyclic delay diversity is a research topic. Over the lifetime, 420 publications have been published within this topic receiving 18031 citations.

A simple transmit diversity technique for wireless communications

Abstract: This paper presents a simple two-branch transmit diversity scheme. Using two transmit antennas and one receive antenna the scheme provides the same diversity order as maximal-ratio receiver combining (MRRC) with one transmit antenna, and two receive antennas. It is also shown that the scheme may easily be generalized to two transmit antennas and M receive antennas to provide a diversity order of 2M. The new scheme does not require any bandwidth expansion or any feedback from the receiver to the transmitter and its computation complexity is similar to MRRC.

A new bandwidth efficient transmit antenna modulation diversity scheme for linear digital modulation

Abstract: A system is proposed and analyzed, which uses several transmit antennas to achieve diversity in a flat fading mobile radio environment. The signals at different antennas carry the same digital information, but have different modulation parameters (modulation diversity). In contrast to other proposals, no bandwidth expansion is required. Modulation diversity for quadrature amplitude modulation (QAM) type modulation is achieved by using different partial response type base pulses. Simulation results confirm the expected gain. >

Standard conformable antenna diversity techniques for OFDM and its application to the DVB-T system

Abstract: In this paper, we investigate different antenna diversity concepts, which can be easily applied to orthogonal frequency division multiplexing (OFDM) systems. The focus is to provide diversity schemes, which can be implemented to already existing OFDM systems without changing the standards. It is also possible to combine these techniques in a suitable manner. The introduced diversity techniques are applied to the DVB-T system for error performance investigations, which were done by simulation.

Cyclic delay diversity for mitigating intersymbol interference in OFDM systems

Abstract: A method and/or an apparatus for mitigating intersymbol interference. In systems which employ transmission diversity when transmitting symbols which have a guard interval, the multiple versions of the transmitted symbols have the samples of the transmitted symbols shifted relative to each version transmitted. The shifted samples of the transmitted symbol are shifted from the end of the transmitted symbol into the beginning of the transmitted symbol. A last number of samples of the transmitted symbol are copied and placed in the guard interval which precedes the symbol. The guard interval and the symbol are transmitted to a receiver.

Spatial transmit diversity techniques for broadband OFDM systems

Abstract: In this paper, we investigate different spatial transmit diversity concepts for orthogonal frequency division multiplexing (OFDM) systems. The idea is to artificially increase the frequency and time selectivity of the resulting channel transfer function at the receiver antenna by specific time-variant phase rotations of the signal at the transmit antennas. The achievable performance gains with the proposed transmit diversity concepts are presented for convolutionally coded OFDM systems in typical indoor and outdoor environments. The new concepts can be implemented in already standardized and existing OFDM systems like DAB and DVB-T or HIPERLAN/2, IEEE 802.11 and MMAC, without changing the standards and the receivers. Moreover, we show further performance improvements by combining the spatial transmit diversity concepts for OFDM with code division multiplexing (CDM).