Harvesting the gain of a large number of antennas in a millimeter-waveband has mainly been relying on the costly operation of channel state information acquisition and cumbersome phase shifters. Recent works have started to investigate the possibility to use receivers based on energy detection (ED), where a single data stream is decoded based on the channel and noise energy. The asymptotic features of the massive receiver array lead to a system where the impact of the noise becomes predictable due to a noise hardening effect. Meanwhile, when the channel has a large number of spatial degrees of freedom, the system becomes robust to imperfect channel knowledge due to channel hardening. We propose two detection methods based on the instantaneous and average channel energy, respectively. Differently from existing works, we analyze the scaling law behavior of the symbol error rate (SER). When the instantaneous channel energy is known, the performance of ED approaches that of the coherent detection in high SNR scenarios. When the receiver relies on the average channel energy, our performance analysis is based on the exact SER, rather than an approximation. It is shown that the logarithm of SER decreases linearly as a function of the number of antennas. Additionally, a saturation appears at high SNR for pulse amplitude modulation constellations of order larger than two, due to the uncertainty on the channel energy. Simulation results show that ED, with a much lower complexity, achieves promising performance both in Rayleigh fading channels and in sparse channels.

Design and Performance Analysis of Noncoherent Detection Systems With Massive Receiver Arrays

The energy detection (ED) receiver is a feasible solution for time of arrival (TOA) estimation in ultra wideband (UWB) ranging. The task of TOA estimation under UWB multipath channel is to determine the first path (FP). In the ED receiver, threshold-crossing (TC) is used a lot. However, the threshold should be elaborately chosen, or else the false detection probability will be high. But it is difficult to acquire the optimal threshold. In the study, we propose a novel method to estimate the TOA based on the received signal characteristics, which are that the TOA of the noise sample that exceeds the threshold is random while the TOA of the FP is definite. The method detects the FP by calculating the frequencies of different samples crossing the thresholds over a sequence of received pulses. Simulation results verify its effectiveness in the IEEE 802.15.4a channels. Comparison results with other methods are also presented to prove the superiority of our method.

TOA Estimation in IR UWB Ranging with Energy Detection Receiver Using Received Signal Characteristics

The recent developments in radio technologies, paves its way to impulse radio (IR) ultra-wideband (UWB) communication, which is used for low power, short range and high bandwidth communication, thereby exploiting a large portion of radio spectrum. In this paper, a brief review of the work done by various researchers on coherent and non-coherent IR-UWB receivers has been analysed, based on their bit error rate (BER) performances, as well as pros and cons of using these receivers. An in depth study on the receivers concludes that, non-coherent IR-UWB receiver is preferred over its counterpart coherent IR-UWB receiver even though it comes at the expense of poor BER performance. The simulation results prove that, though the performances are same, the low complexity of energy detector (ED) receivers gives an edge over the autocorrelation receivers. Further, ED receiver suffers from noise, which paves way to using weighted ED (WED) receiver. The superiority of WED receivers over all the other non-coherent UWB receivers is further confirmed by the simulation performed in AWGN and IEEE 802.15.4a UWB channels. It can also be concluded from the review that, some special receivers such as generalized likelihood ratio test, multi-symbol differential detector and decision feedback differential transmitted reference, when clubbed with UWB systems, lead to further improvement in BER performance.

A Survey on Various Coherent and Non-coherent IR-UWB Receivers

In this paper, a joint multi-user constellation is proposed for energy detection-based non-coherent massive multiple-input multiple-output system. This is motivated by the simple design and high energy efficiency it entails for both the transmitter and receiver. First, the orthogonal codes is employed to suppress the multi-user interference. However, this comes at the price of consuming more communications resources. In this study, the key to reduce code redundancy is the design of a joint constellation since it makes energy detection applicable when multiple users employ the same orthogonal codes. Although it is unsolvable initially, our analysis indicates that through minimizing the symbol-error rate (SER), the joint constellation design becomes feasible. Concretely, two analytical expressions of SER based on Gamma and Gaussian distributions are derived. Via minimizing the error probability, an important result that the joint constellation should satisfy is obtained. Accordingly, an isometric constellation design is proposed to find constellations that enable non-coherent reception with multiple users, and reduce SER simultaneously. In addition, decoding regions of symbol decision are optimized to further improve the error performance. In the end, numerical simulations are carried out to highlight the effectiveness of our proposed scheme.

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Non-Coherent Massive MIMO Systems: A Constellation Design Approach

We propose the use of energy detection for single stream transmission and reception by a very large number of antennas, with primary application to millimeter wave communications. The reason for applying energy detection is low complexity, cost and power efficiency. While both energy detection and millimeter wave communications are limited to short ranges due respectively to noise sensitivity and propagation attenuation, processing by a large number of receive antennas overcomes those shortcomings to provide significant reach extension. This processing is solely based on long-term statistics of the channel and noise, making it robust to user mobility and imperfect channel knowledge.

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Energy detection using very large antenna array receivers

For ultra-wideband (UWB) impulse radios, noncoherent energy detectors are motivated for their simple circuitry and effective capture of multipath energy. A major performance-degrading factor in energy detection is the noise floor, which is aggravated for low-duty-cycle UWB signals with a large time-bandwidth product. In this paper, weighted energy detection (WED) techniques are developed for effective noise suppression. The received signal is processed by a set of parallel integrators, each corresponding to a different integration time-window within a symbol period. The outputs of these integrators are weighted and linearly combined to generate decision statistics, while the weights are determined by the signal power collected from the corresponding integrators to improve the effective signal to noise ratio. The WED principle is applied to all phases of receiver processing, including signal detection, timing synchronization and data demodulation. For each phase, the optimal linear detector parameters, including decision thresholds and weighting coefficients, are derived analytically. Simulations show that the proposed noncoherent WED receiver enhances the bit-error-rate performance compared to conventional energy detectors.

Weighted Energy Detection for Noncoherent Ultra-Wideband Receiver Design

In the presence of narrowband interference (NBI), detection of weak wideband signals faces foremost challenges in analog-to-digital conversion (ADC), due to the dynamic range problem encountered when the weak signal cannot be amplified adequately to achieve sufficient quantization accuracy. Building on a parallel frequency-domain sampling structure for ADCs, this letter derives a new quantization bit allocation scheme that effectively removes strong NBI. Frequency bins hosting NBIs are allocated with no quantization bits. Optimal rules for symbol detection and quantization bit allocation are derived by jointly minimizing the mean square error of the decoding output.

Wideband receiver design in the presence of strong narrowband interference

This paper proposes a 110% relative bandwidth (RBW) low-noise amplifier (LNA) for broadband receivers with flat gain, low noise and high linearity. Bias and parasitic parameters derived wide bandpass (BPDWB) matching networks and a cascode with dual feedbacks are introduced for broadband performance. Matching network design procedures are demonstrated, and results show that the frequency response of the network fits the target impedance well from 1 GHz to 3.5 GHz. The proposed BPDWB network improves the design efficiency and enhances the prediction accuracy of impedance matching. The proposed LNA in 0.25 μm GaAs pseudomorphic high electron mobility transistor (GaAs pHEMT) technology realizes a minimum NF of 0.45 dB at 1.6 GHz where the NF is less than 0.55 dB within the operating frequency band. A flat gain of 22.5–25.2 dB is achieved with the input voltage standing wave ratio (VSWR) below 1.22 and output VSWR less than 2.5. In addition, the proposed LNA has good linearity where the output third-order intercept point (OIP3) is better than +31.5 dBm, and the output 1 dB compression point (OP1dB) is better than +19 dBm over the wide frequency range.

/pdf/analysis-and-design-of-a-wideband-low-noise-amplifier-with-3gtdim14.pdf

Feng Wang

Papers

Weighted Energy Detection for Noncoherent Ultra-Wideband Receiver Design

Wideband receiver design in the presence of strong narrowband interference

Analysis and Design of a Wideband Low-Noise Amplifier with Bias and Parasitic Parameters Derived Wide Bandpass Matching Networks