Continuous phase modulation (CPM) has gained increasing attention due to its favorable trade-off between power and bandwidth efficiency. Multi-h CPM appeared as a generalization of single-h schemes so as to decrease further the need for bandwidth expansion over the wireless channel. Despite the interesting characteristics of CPM, the decoding of the received signal is particularly difficult in a multi-path wireless environment with no diversity. To provide some level of diversity, several authors have proposed to combine CPM with Space-Time Block Coding (STBC). A new family of codes for CPM, based on L 2 -orthogonality was recently introduced in [8]. These full rate codes achieve full diversity and a low decoding complexity.In this paper, we detail a non trivial extension of these L 2 -orthogonal Space-Time codes using multi-h signaling schemes. These new codes achieve full diversity and a better spectral compactness by utilizing the available communication bandwidth more efficiently. Also, the decoding complexity is greatly decreased by using only one correlation filter bank for the detection of all transmitted signals.

International audienceWireless Robotics has become an important research topic in the last two decades. The need of controlling a robot to perform tasks remotely has significantly increased with the number of applications in fields like medicine and military, among many others. Taking advantage of current standards like Bluetooth and Wifi, Wireless Robotics calls for low power consumption components, robustness and high data rate through the wireless channel. This call can be fulfilled with a reliable signaling format, satisfying the needs of low power consumption and high spectral efficiency. Besides, continuous phase modulation (CPM) has gained increasing attention due to its favorable trade-off between power and bandwidth efficiency. Multi-h CPM recently appeared as a generalization of single-h schemes so as to further decrease the need for bandwidth expansion over the wireless channel. Despite the interesting characteristics of CPM, the decoding of the received signal is particularly difficult in a multi-path wireless environment with no diversity. To provide some level of diversity, several authors have proposed to combine CPM with space-time block coding. A new family of codes for CPM, based on L2-orthogonality was recently introduced [Hesse et al. 2011]. These full rate codes achieve full diversity and a low decoding complexity. In this paper, we detail a non trivial extension of these L2-orthogonal space-time codes using multi-h signaling schemes. These new codes still achieve full diversity but a better spectral compactness by utilizing the available communication bandwidth more efficiently. Also, the decoding complexity is greatly decreased by using only one correlation filter bank for the detection of all transmitted signals

International audienceOrthogonal Space-Time Block Codes (STBC) with Multiple-Input Multiple-Output (MIMO) systems have become a very popular way of adding spatial diversity to transmissions. Orthogonal Frequency Division Multiplexing (OFDM) is a modulation technique to further increase the robustness against frequency selective fading at high data rates. Some authors have then proposed to combine both: linear STBC codes with OFDM; however, with a major weakness: high Peak to Average Power Ratio (PAPR). Using instead Continuous Phase Modulation (CPM) to get constant envelope signals to reduce PAPR, CPM-OFDM can take advantage of a favorable trade-off between power and bandwidth efficiency given by CPM with the well-known robustness to frequency selective fading of OFDM. To further increase the data throughput, while maintaining robustness to frequency selective fading and low PAPR, we introduce here a new space-time-frequency diversity technique based on MIMO OFDM using L2-orthogonal multi-h CPM STBC codes. We benchmark these schemes under Rayleigh frequency selective channels with semi-coherent detection and show how they achieve improved spectral compactness while providing a low decoding complexity by the use of a simplified Zero-Forcing (ZF) detection/correlation algorithm

International audienceOrthogonal Frequency Division Multiplexing (OFDM) is a popular modulation technique that provides high data rates and good robustness against frequency selective fading. Space-Time Block Coding (STBC) is an efficient way to introduce space-time diversity in Multiple-Input Multiple-Output (MIMO) systems. Using non-linear modulations such as Continuous Phase Modulation (CPM) with its constant envelope and continuous phase properties could be a solution to construct MIMO OFDM systems and to avoid the structural limitations of linear codes and alleviate the typical PAPR issue of OFDM. However, a major issue with CPM based systems may remain: the decoding complexity. In this paper, we introduce a new space-time-frequency diversity technique based on L2-orthogonal multi-h CPM Space-Time codes designed for OFDM transmission. We benchmark these codes under Rayleigh frequency selective channels and show how they achieve full spatial diversity at full rate for any number of antennas, good spectral compactness and also robustness to frequency fading. Furthermore, the decoding complexity is highly reduced and even made linear in the number of antennas thanks to the orthogonality properties

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