Signal Format Research Articles

Application of the Joint Fast Walsh Hadamard-Inverse Fast Fourier Transform in a LDPC Coded OFDM Wireless Communication System: Performance and Complexity Analysis

An efficient low complexity T transform which combines the Walsh Hadamard Transform and Discrete Fourier Transform (DFT) into a single fast orthonormal unitary transform is considered for the application in low density parity check coded orthogonal frequency division multiplexing (LDPC-OFDM) across additive white Gaussian noise channel model and multipath fading channel models. The T-transform is developed through the sparse matrices factorization method using Kronecker product scheme. T-transform based COFDM system, which is capable of reducing peak to average power ratio (PAPR) of the transmitted symbols and improving the bit error rate (BER) performance at a reasonable reduced complexity. Several signaling formats such as Quadrature phase shift keying and 16- ary Quadrature amplitude modulation (16-QAM) are considered. A T COFDM system is described which could provide an alternative to DFT-COFDM system, and is therefore a better alternative to balance the transform complexity, PAPR reduction and system performance. Simulation results are used to examine and compare the complexity, PAR and the BER performance of T-OFDM system and DFT-OFDM system. Numerical results show that the T-COFDM system outperforms the DFT-COFDM based in the multipath channel models.

A Novel Joint RFID and Radar Sensor Network for Passive Localization: Design and Performance Bounds

Nowadays, passive and semi-passive wireless devices are increasing their appeal, particularly in the new scenario of the Internet of Things, thanks to their low complexity and low energy consumption. In this context, radio-frequency identification (RFID) and radar sensor networks (RSNs) are rising interest when the localization of (semi-)passive tags (without active transmitters) and moving passive objects is required. In this paper, we propose a novel network architecture capable of jointly localizing (semi-)passive tags and moving passive objects through the analysis of their backscattered response. The reciprocal interference in objects/tags localization arising from the signal variations caused by objects' and tags' movement is characterized. We present an analytical derivation, based on the Cramer-Rao bound, providing the theoretical localization accuracy of tags and passive objects. The proposed approach represents a fundamental design tool providing insights on how system parameters (power and signal format), network topology, interference, and network configuration (monostatic or multistatic) affect the localization performance.

Performance analysis of optical CDMA communication systems with M‐ary PWM signalling

ABSTRACTIn this paper, a novel M‐ary pulse‐width modulation (PWM) coded optical code division multiple access (O‐CDMA) system is proposed. At the transmitter end, in order to increase the number of transmitted bits per pulse, each chip of signature sequence is further divided into M time slots to realise the M‐ary PWM signal format. Two types of detection schemes are developed, and the performance in terms of symbol error rate is analysed. In the first scheme, the correlation receiver is employed followed by an M‐level threshold detection. To enhance the multiuser interference suppression capability, we apply the chip‐level‐based diversity detection in the second scheme. Adding optical hard‐limiters at the front end of the receiver, both schemes are free from the near–far problem that is suffered severely in O‐CDMA system employing pulse‐amplitude modulation (PAM). Numerical results demonstrate that the proposed M‐ary PWM O‐CDMA system with the chip‐level receiver achieves better symbol error rate and multiuser interference mitigation capability than the correlation receiver. Moreover, the performance of the proposed M‐ary PWM O‐CDMA system is much better than the M‐ary pulse‐amplitude modulation scheme. And the complexity is substantially reduced as we compare to the existing M‐ary pulse‐position modulation O‐CDMA system. Copyright © 2014 John Wiley & Sons, Ltd.

SCCC Turbo Equalizer/Decoder for X-band Nano Satellite High-Speed Downlink System

Nano satellite technologies have been recognized as potential candidates for new satellite applications. We have developed a X-band downlink system for nano satellite employing Consultative Committee for Space Data Systems (CCSDS) 131.2-B-1 signaling formats with a modulation symbol rate of 100 Msps. Since nano satellites with a mass of less than 50 kg have more constraints than typical large satellites, the received signals of nano satellites tend to suffer much more distortion due to the system and channel constraints. To compensate for the distortion, several techniques have been developed to provide higher data rate than 100 Mbps for nano satellites. At the transmitter, a look-up table (LUT) based digital predistorter for memoryless AM/AM and AM/PM nonlinearities is designed to mitigate nonlinearity of power amplifier (PA) and IQ-imbalance of quadrature modulator. At receiver side, a soft interference canceller (SIC) turbo equalization combined with SCCC turbo decoder has developed to overcome nonlinear/linear distortion using iterative techniques. For 16-QAM modulation, a nonlinear compensation technique based on centroid estimation at the receiver is also developed to correct constellation points of received signals. The techniques are modeled and verified via computer simulation; therefore, the obtained results apply to the downlink system designs of the nano satellite, Hodoyoshi 4.

A Single RF MIMO Loading Network for High-Order Modulation Schemes

Recently, a novel MIMO transmitter architecture has been introduced that requires only a single radio-frequency (RF) chain and is built on parasitic antenna arrays. MIMO transmission in this case is achieved by shaping directly the radiation pattern with the aid of analog tunable loads attached to the parasitics. As it has been shown, such a single RF MIMO system can support all PSK modulation formats with purely imaginary loading values. This paper extends its capabilities and proposes a novel architecture for parasitic antennas that is able to providecomplexloading values, even with a negative real part. Definitely, this will extend the flexibility of parasitic antennas to multiplex successfully over the air more complex signaling formats, for example, QAM signals. The bit error rate evaluation shows that the proposed architecture could be very promising in emerging devices and also illustrates its robustness under possible loading perturbations that might have been raised due to nonidealities in the design.

재구성형 주변장치유닛을 사용한 유무선 LED 조명 통신

본 논문에서는 LED 조명 통신을 위한 재구성형 주변장치유닛을 제안한다. 조명시스템을 위한 임베디드 장치에서는 다양한 통신 프로토콜이 요구된다. 이러한 통신 프로토콜로는 UART, SPI, IrDA 등의 직렬 통신, DALI나 DMX512와 같은 조명제어 통신이 있다. 다양한 통신 프로토콜 요구사항을 각 IP로 개별 구현하여 만족시킬 경우 비용 및 전력 효율이 떨어질 수 있다. 본 논문에서는 각 프로토콜의 신호 형식을 분석하여 UART, SPI, IrDA, DALI, DMX512의 통신 기능을 통합하는 방법을 제안한다. 제안한 재구성형 주변장치유닛은 개별 구현 방법에 비해 57% 감소된 양의 게이트수를 사용한다. 또한 본 논문에서는 조명 네트워크를 유연하게 구현하기 위해 사용될 수 있는 매핑테이블 기반의 DALI-ZigBee 인터페이싱 방법을 제안한다. 이 방법을 사용하면 DALI와 ZigBee를 혼용한 다양한 구성의 조명 네트워크 시스템을 효율적으로 구현할 수 있다. LED 조명시스템 플랫폼을 구성하여 유무선 조명 통신 네트워크의 동작을 검증하였다. 본 논문에서 제안한 재구성형 주변장치유닛과 DALI-ZigBee 인터페이싱 방법은 유무선 조명시스템을 효율적으로 구현하는 데에 사용될 수 있다. In this paper, a reconfigurable peripheral unit for LED lighting communication is presented. Embedded lighting devices require various communication protocols. Usually, serial communication protocols and lighting control communication protocols such as DALI, DMX512, UART, SPI, IrDA, etc. are used in lighting devices. When the requirements of communication protocols are satisfied with separate IPs, the cost and the power consumption can considerably increase. We propose a reconfigurable communication peripheral unit which uses analysis of signal formats of the protocols. The gate count of the reconfigurable peripheral unit uses only 57% of the gate count of the separate implementation. Also, in this paper, a mapping table based DALI-ZigBee interfacing method for flexible lighting network configurations is proposed. Using this method, various DALI-ZigBee network systems can be easily set up. An LED lighting system platform is implemented to verify the operation of the DALI-ZigBee interfacing method. The reconfigurable peripheral unit and the DALI-ZigBee interfacing method can be efficiently used to implement various wired/wireless lighting communication systems.

Investigation on inter-modulation products (IMPs) for IM-DD SCM optical links

The implementation of the subcarrier multiplexing (SCM) as the signaling format has been extensively researched in various analog and digital lightwave based broadband applications because of its promising versatility, cost effectiveness, convenient and simple offerings. However performance degradation is a matter of serious concern in such multi-channel intensity modulation-direct detection (IM-DD) systems caused by inter-modulation distortion (IMD) mechanism. In this paper the impact of key operational and physical parameters of a laser source on an IMD dominated two-tone IM-DD SCM system has been investigated which can thereby be exploited favorably to develop a reasonably IMD immune optical link.

Radio-over-fiber transport systems with an innovative phase modulation to intensity modulation converter

Robust optical phase modulation (PM) schemes have been widely employed in the development of radio-over-fiber (RoF) transport systems. However, the signals produced by these PM schemes require a delay line interferometer (DI), a fiber Bragg grating (FBG), an optical band-pass filter (OBPF), or dedicated dispersive devices to convert them back into the intensity modulation (IM) signal format prior to detection by a photodetector (PD). Inserting a costly DI into a transport link can significantly increase overall cost, and the use of a fixed working window OBPF, FBG, or dedicated dispersive devices to achieve the conversion is inflexible. To overcome these problems in PM-based RoF transport systems, a long-reach RoF link with an innovative PM-to-IM converter is proposed and experimentally demonstrated. Compared with the published PM schemes, the proposed architecture can utilize a vertical-cavity surface-emitting laser (VCSEL) to achieve the same performance of the published PM-to-IM converter at a lower cost. In addition, by adjusting the VCSEL driving current, a tunable range exceeding 350 GHz is experimentally obtained for the converter working window. The proposed long-reach RoF transport system is the first to achieve such PM-to-IM conversion by using a VCSEL and can contribute to the development of RoF transport systems.

Spectral Precoding for Cyclic-Prefixed OFDMA With Interleaved Subcarrier Allocation

Spectrally precoded orthogonal frequency-division multiple access (OFDMA) using cyclic prefix and interleaved subcarrier allocation (IOFDMA) is a useful rectangularly pulsed OFDMA signaling format for it exploits high spectral compactness and frequency diversity characteristics. In this paper, two new spectral precoders of the largest precoding rate are developed for IOFDMA in order to provide improved spectral compactness and reduce implementation complexity, respectively. Specifically, a new correlative precoder is developed and shown to minimize the dominant spectral coefficient among all correlative precoders of the largest precoding rate and thus can construct IOFDMA signals providing extremely high spectral compactness. Besides, a multiple-stage spectral precoding technique is proposed to construct a low-complexity orthogonally precoded IOFDMA with power spectral sidelobes decaying as f^{-2L-2} for L>1, where L is the number of stages. The corresponding orthogonally precoded IOFDMA signals conveying independent zero-mean data are shown to provide the same power spectrum as existing orthogonally precoded IOFDMA signals of the largest precoding rate while requiring much less complexity.

Reverse polarity optical-OFDM (RPO-OFDM): dimming compatible OFDM for gigabit VLC links

Visible light communications (VLC) technology permits the exploitation of light-emitting diode (LED) luminaries for simultaneous illumination and broadband wireless communication. Optical orthogonal frequency-division multiplexing (O-OFDM) is a promising modulation technique for VLC systems, in which the real-valued O-OFDM baseband signal is used to modulate the instantaneous power of the optical carrier to achieve gigabit data rates. However, a major design challenge that limits the commercialization of VLC is how to incorporate the industry-preferred pulse-width modulation (PWM) light dimming technique while maintaining a broadband and reliable communication link. In this work, a novel signal format, reverse polarity O-OFDM (RPO-OFDM), is proposed to combine the fast O-OFDM communication signal with the relatively slow PWM dimming signal, where both signals contribute to the effective LED brightness. The advantages of using RPO-OFDM include, (1) the data rate is not limited by the frequency of the PWM signal, (2) the LED dynamic range is fully utilized to minimize the nonlinear distortion of the O-OFDM communication signal, and (3) the bit-error performance is sustained over a large fraction of the luminaire dimming range. In addition, RPO-OFDM offers a practical approach to utilize off-the-shelf LED drivers. We show results of numerical simulations to study the trade-offs between the PWM duty cycle, average electrical O-OFDM signal power, radiated optical flux as well as human perceived light.

CSRZ 신호의 클럭 성분을 이용한 색분산 감시법에서 송수신단 대역폭의 영향 분석

광통신 시스템에서는 제한된 대역폭에서 최상의 성능을 얻기 위해 다양한 신호형태가 사용되고 있다. 그중에서도 CSRZ (carrier-suppressed return-to-zero) 신호는 스펙트럼 효율이 높으면서도 색분산에 대해 비교적 강인한 특성을 지니고 있어 많이 사용되고 있다. 우리는 이러한 CSRZ 신호의 중요성을 파악하고, 이전의 연구에서 CSRZ 신호의 클럭 (clock) 성분을 이용하여 색분산을 감시하는 방법을 제시한 바가 있다. 하지만, 클럭 성분을 이용하여 색분산을 감시하는 방법은 송수신단의 대역폭에 의해 그 영향을 받을 수 있다. 따라서, 본 논문에서는 CSRZ 신호에서 송수신단의 대역폭이 클럭 성분을 이용한 색분산 감시법에 미치는 영향을 분석하고, 송수신단의 대역폭이 변하더라도 그 성능이 유지될 수 있는 강인한 클럭 추출법을 제시한다. In optical fiber communications, several newly-developed signal formats are used to obtain the best performance within limited spectral bandwidth. CSRZ (carrier-suppressed return-to-zero) format is one of the new signal formats, which has better spectral efficiency and better robustness to dispersion than RZ (return-to-zero) format. Thus it is widely used for demonstrating high-speed optical communication systems. In an earlier research, we proposed a clock-extraction method of CSRZ signal to monitor chromatic dispersion. However, the clock-frequency component extracted by the clock-extraction method can be affected by the bandwidth of a transmitter or a receiver. Therefore, in this paper, we investigate the effect of bandwidth on the chromatic dispersion monitoring of CSRZ signal based on clock-frequency component. As a result, we propose a couple of robust clock-extraction methods to monitor chromatic dispersion in CSRZ signal.

3D beamforming: Performance improvement for cellular networks

The beam pattern of a mobile communication base station has significant impact on the performance of a cellular network. Three-dimensional (3D) beamforming combines the horizontal beam pattern adaptation, as applied for beamforming and multiple input multiple output (MIMO) schemes, with a vertical antenna pattern adaptation. The recent availability of new flexible antenna techniques enables a fully dynamic antenna pattern adaptation which can be specified per resource block and user equipment (UE), and makes 3D beamforming practically feasible. This paper describes the basic principles of 3D beamforming, including the impact of downtilt adaptation on the physical layer as well as the potential of its combination with beam coordination involving the media access control (MAC) layer. Our investigations assumed the vertical main lobe of the beam pattern was geometrically pointed towards the UE. We discuss a number of different realization options and simulation results including a Bell Labs field trial with vertical beam steering. Using wireless systems with state of the art Long Term Evolution (LTE) signal format and including the lightRadio™ antenna array, our trials in the Stuttgart testbed verified the basic predicted properties and potential advantages of 3D beamforming.

Improving the Spectral Efficiency of Nonlinear Satellite Systems through Time-Frequency Packing and Advanced Receiver Processing

We consider realistic satellite communications systems for broadband and broadcasting applications, based on frequency-division-multiplexed linear modulations, where spectral efficiency is one of the main figures of merit. For these systems, we investigate their ultimate performance limits by using a framework to compute the spectral efficiency when suboptimal receivers are adopted and evaluating the performance improvements that can be obtained through the adoption of the time-frequency packing technique. Our analysis reveals that introducing controlled interference can significantly increase the efficiency of these systems. Moreover, if a receiver which is able to account for the interference and the nonlinear impairments is adopted, rather than a classical predistorter at the transmitter coupled with a simpler receiver, the benefits in terms of spectral efficiency can be even larger. Finally, we consider practical coded schemes and show the potential advantages of the optimized signaling formats when combined with iterative detection/decoding.

3D origami electrochemiluminescence immunodevice based on porous silver-paper electrode and nanoporous silver double-assisted signal amplification

A highly sensitive electrochemiluminescence (ECL) immunosensor combined with a 3D origami device for detection of carcinoembryonic antigen (CEA) was developed based on novel porous silver nanoparticles modified paper working electrode (Ag-PWE) as sensor platform and CdTe quantum dots functionalized nanoporous silver (QDs/NPS) as signal amplification label. The microfluidic origami device was fabricated by directly screen-printed electrodes on wax-patterned cellulose paper in bulk. The Ag-PWE was fabricated by a seed-mediated growth approach and served as an effective matrix for antibody attachment with good bioactivity, and stability. The ECL nanoprobe (Ab2/QDs/NPS) was designed by covalent assembly of signal antibodies (Ab2) on QDs/NPS. After a sandwich immunoreaction, the functionalized NPS labels were captured onto the Ag-PWE surface. On the basis of the considerably amplified ECL signal and sandwich-type format, the proposed method successfully fulfilled the highly sensitive detection of CEA with a linear range of 0.5pgmL−1 to 20ngmL−1 with a detection limit of 0.12pgmL−1. This facile origami ECL immunodevice exhibited high sensitivity, specificity and excellent performance in real human serum assay, and could be applied in point-of-care testing of other tumor markers for remote regions and developing countries.

Low-complexity synchronization algorithms for orthogonally modulated IR-UWB systems

Timing synchronization is a major issue for any communication system since it is essential to ensure its stable operation and reliable performance. In this paper, we compare two low-complexity synchronization algorithms for impulse radio ultra-wideband (IR-UWB) system, employing orthogonal pulse shape modulation (PSM). The two widely adopted modulation schemes for IR-UWB systems are binary pulse amplitude modulation and binary pulse position modulation. However, the possibility of generating orthogonal UWB pulses in recent years has motivated the use of orthogonal PSM which is particularly attractive as high-order modulation and also due to its possible robustness against ISI, and therefore is the focus of this paper. Relying on the unique signal format, the first algorithm applies simple overlap-add operation followed by energy detection to achieve synchronization. This approach is semi non-data-aided (NDA) because a part of the signal is specifically reserved to help enable synchronization. The other algorithm, on the other hand, exploits the discriminating nature of well-designed polarity codes and employs a series of code word matching and averaging operations to achieve synchronization. This approach is full NDA as there is no need to interrupt the data transmission. Based on the judicious change in the phase of transmitted signal applied for synchronization purposes, the second algorithm can also be used to extract synchronized aggregate templates. These templates are then used in demodulation, resulting in a low-complexity non-coherent alternative to complex Rake receivers. The two compared timing algorithms rely on simple overlap-add operations and thus remain operational under practical UWB settings. Simulation results are provided to demonstrate the efficient performance of proposed timing estimators.

Design of Directly Modulated Long-Reach PONs Reaching 125 km for Provisioning of Hybrid Wired–Wireless Quintuple-Play Service

Design tools for the quintuple-play service provisioning in a long-reach passive optical network (LR-PON) using off-the-shelf directly modulated lasers (DMLs) are experimentally demonstrated. The quintuple-play service including broadband wired Internet, phone/voice data, wireless high-definition TV, wireless data, and home security/control is provided by a radio-over-fiber bundle of multi-format orthogonal frequency division multiplexing (OFDM) signals. This bundle occupies a multi-octave band and consists of a full-standard worldwide-interoperability-for-microwave access signal, a long-term evolution signal, two ultra-wideband channels, and an ad hoc OFDM signal providing gigabit Ethernet connectivity. Dynamic centralized impairment compensation, fixed optical dispersion compensation, proper selection of the multiplexed signal level applied to the DML, and unbalanced power sharing between the different OFDM-based signal formats are shown as effective design tools for the delivery of the quintuple-play service to end-users. The experimental validation confirms that the DMLs are an effective solution to deliver the quintuple-play service to end-users 125 km away from the central office. Additionally, it is shown that the directly modulated LR-PON employing negative residual dispersion is able to provide the quintuple-play service to end-users located between 75 and 125 km away from the central office with an error vector magnitude (EVM) margin, relative to the EVM stated in each signal standard, by more than 1 dB. Therefore, the proposed directly modulated LR-PON is a cost-effective alternative to networks using external modulation for the provision of wireless and wired quintuple-play service to end-users using a single hybrid network.

P.34: A Video Signal Coding Method Based on an Absolute Color Space for Saving Bit Depth

AbstractA coding method based on CIE u'v' is proposed for saving bit depth. The signal format comprises a luminance component and a chromaticity component. An example shows that 27 bits are required so that a display following UHDTV could be able to reproduce color‐banding free picture under any luminance adaptation.

Abstract 4778: Dissecting the gender disparity of hepatocellular carcinoma: roles of HBV X protein and androgen receptor.

Abstract Hepatocellular carcinoma (HCC) is a leading cancer worldwide and especially prevalent in Southeast Asia, due to prevalent hepatitis B virus (HBV) infection. HBV-associated HCC has a male predominance, with a male-to-female ratio of about 4-5:1. HBV is a partially double-stranded DNA virus containing four overlapping open reading frames. Among them, X gene is most frequently integrated into host genome naturally and plays an important role in hepatocarcinogenesis. In male HBV carriers, the risk of HCC development is significantly increased in those with higher serum androgen and androgen receptor (AR) activity. HBV infection may, therefore, particularly cooperate with male-specific AR signalling to accelerate hepatocarcinogenesis. In this study, we hypothesized that HBx cooperated with male-specific AR signalling to enhance hepatocarcinogenesis, and natural HBx truncated mutants exerted different effects on this AR signalling. Firstly, we demonstrated that the expression of androgen receptor was significantly higher in the HCC cells when compared to the immortalized non-tumorigenic normal liver cell lines (LO2 and MIHA). Moreover, the HCC cell lines with higher metastatic potential (MHCC-97L, MHCC-97M and LM3) had a higher AR protein expression level, suggesting a role of AR in HCC development and progression. In human HBV-associated HCC tissues, we found that the natural COOH-terminal truncated HBx was more frequently detectable in HCC tumors from male than female patients (43% and 11%, respectively). Here, we also showed that the natural COOH-terminal HBx truncated mutants HBx ΔC3 (1-95 a.a) and HBx ΔC4 (1-89a.a) physically interacted with AR, indicating the possibility of HBx ΔC3 and HBx ΔC4 in regulating AR activity and the binding of HBx with AR at its N-terminal part. Furthermore, we demonstrated that HBx truncated mutants localized in the nuclear fraction, unlike the full-length HBx protein which localized in the cytoplasm. The capability of the nuclear translocation may suggest a role of the HBx truncated mutants in regulating AR transcriptional activity. In addition, androgen induced the expression of GADD45, a DNA damage-inducible gene, in HCC cells. The androgen-induced GADD45 expression was even higher with the co-expression of full-lengthen HBx protein, demonstrating a synergistic effect between HBx and AR in inducing DNA damage and genetic instability in HCC cells. Taken altogether, these findings may provide a linkage between HBx, AR signaling, genomic instability and HCC carcinogenesis Citation Format: Yung Tuen Chiu, Irene Oi Lin Ng. Dissecting the gender disparity of hepatocellular carcinoma: roles of HBV X protein and androgen receptor. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4778. doi:10.1158/1538-7445.AM2013-4778

Uplink transmission in the W-band (75-110 GHz) for hybrid optical fiber-wireless access networks

We report on an experimental, W-band, uplink for hybrid fiber-wireless systems which enables high speed communication from the wireless end users to the central server. Overall system performances for an OFDM signal format are discussed in detail. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1033–1036, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27476

Wireless Robotics: Generalization of an Efficient Approach with Multi-h CPM Signaling and L2-Orthogonal Space-Time Coding

Wireless 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 $$L^2$$ -orthogonality was recently introduced in Hesse et al. (IEEE Trans Commun 59(11): 3158---3166, 2011). 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 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.