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Underwater acoustic sensor networks are characterized by limited transmit power and bandwidth, and a harsh communication environment. Different techniques for reliable communication in underwater networks have been studied in the literature at different layers of the network protocol stack. Among these, the use of fountain codes as a way for improving the quality of the communication over a highly...
This paper presents a 1/4-rate PAM4 receiver employing a sampling decoder with an adaptive variable-gain rectifier (AVGR) to achieve a bit efficiency of 1.38 pJ/bit. By concurrently performing gain adaptation and amplitude rectification for decoding the least significant bit (LSB), the proposed decoder greatly reduces power consumption compared with the conventional full-rate topology using three...
In a MIMO wireless communications system, a space-time block code specifies how the data symbols are transmitted over different antennas at different time instants. A hybrid space-time code attempts to obtain some of the available diversity and multiplexing gains, achieving low error probability and high data rate. The LD StBc-VBLAST hybrid code layers one spatial-multiplexing antenna (to increase...
This paper describes an energy-efficient PAM-4 digital receiver based on sequence detection. This scheme takes advantage of the ISI in the channel to reconstruct the time domain 5-bit sequence including MSB and LSB. The architecture also enables built-in error correction with very low latency. This concept is demonstrated with prototype implemented in a 28nm FDSOI CMOS using only 18-data comparators...
We consider a visible light communication (VLC) system with light emitting diodes (LEDs), wherein LEDs are used for information transmission as well as reception while providing illumination. At the transmitter, a combination of a pulse width modulation (PWM) signal and a redundant run-length limited encoded on-off keying (OOK) signal is used for data transmission. The LED receiver uses OOK and the...
Transmission techniques based on channel coding with feedback are proposed in this paper to enhance the security of wireless communications systems at the physical layer. Reliable and secure transmission over an additive noise Gaussian wiretap channel is investigated using Bose-Chaudhuri-Hocquenghem (BCH) and Low-Density Parity-Check (LDPC) channel codes. A hybrid automatic repeat-request (HARQ) protocol...
To satisfy the requirements of complex distributed power electronic system (PES) communication, this paper has proposed a single optic-fiber link data communication protocol based on the Manchester code due to an vacancy in the commonly-adopted protocols, analyzed the encoding and decoding principle of Manchester code, defined the formats of command frame and data frame, calculated the communication...
This paper investigates the energy harvesting fading multiple-access channels, where the transmitters harvest random amounts of energy from the environment and the data transmissions are subject to statistical quality of service (QoS) constraints in the form of limitations on the buffer overflow probability. With the assumption that the channel state information (CSI) and harvested energy in all time...
Interference alignment (IA) is a prospective method to manage interference between users in multi-user networks. On the other hand, jamming can be an effective way to combat adversarial eavesdropping for legitimate networks. In this paper, a beneficial jamming scheme is proposed for interference alignment networks. In the scheme, the jammer utilizes its precoding vector to constrain the jamming signal...
In recent years, numbers of non-orthogonal multiple access (NOMA) schemes have been proposed to support the great amounts of wireless connections. However, complex multi-user detection is needed in case that the user power differentiation is not available and simple successive interference cancellation cannot directly apply, which usually incurs unaffordable computational complexity. In this paper,...
Massive machine type communication (mMTC) is one of the three significant scenarios in 5G, which is characterized by massive connection and low energy consumption. To meet these requirements, the contention based grant-free sparse code multiple access (SCMA) transmission which can support a large number of devices and reduce the cost of signaling overhead caused by massive connection is proposed....
We propose an underlay decode-and-forward cognitive (UDFC) scheme under joint effects of hardware impairments at secondary users and interference constraints at multi primary receivers. In this scheme, the transmit powers of a source node and relays are constrained by interference thresholds of primary receivers in which the best relay is selected has the highest decoding capacity from the source...
Mobile phone front-end and baseband modules are hard to obtain on the market for end customers. Thus, software defined radios are widely used in research and development, enabling many opportunities for digital signal processing. In this publication a novel option to receive GSM signals is suggested by using an ultra-low power Sub-GHz transceiver in a legacy mode. The device outputs raw demodulated...
We consider polar coded BPSK receiver performance improvement based on the concepts of channel log-likelihood ratio (LLR) approximation and the maximum achievable transmission rate on fading channel. Based on symmetry condition of random variables, uniform scaling factors are applied to correct soft messages at the absence of channel state information (CSI) at the receiver side. The searching method...
Polar codes were recently chosen to protect the control channel information in the next-generation mobile communication standard (5G) defined by the 3GPP. As a result, receivers will have to implement blind detection of polar coded frames in order to keep complexity, latency, and power consumption tractable. As a newly proposed class of block codes, the problem of polar-code blind detection has received...
In this paper, we propose a feedback-aided irregular repetition slotted ALOHA (F-IRSA) protocol which depends on the distance between the received packet and the set of packets already recovered at the receiver. We employ feedback messages to terminate the user retransmission process, and use successive interference cancellation (SIC) for packet recovery. We evaluate the number of transmissions per...
Increased demand for wireless services has spurred research into spectrum co-existence between radar and communication systems. The effect of an unaltered radar interference on an uncoded communication receiver has been investigated for constellations used in commercial systems. However, the constellation design — possible for a cognitive transmitter-receiver pair — that maximizes the transmission...
In this work, we implement and demonstrate differential amplify-and-forward (DAF) cooperative relaying as a novel diversity technique to combat bit errors and outages common in airborne environments. By using differential modulation and demodulation, we reduce the system complexity by avoiding channel estimation which is often unreliable or computationally costly in dynamic environments with mobile...
We consider a communication problem in which a transmitter encodes a source into several streams that are subject to modification by an omniscient adversary while en route. We design encodings with a distortion guarantee that degrades gradually as the number of streams that the adversary alters increases. Notably, we find that a mixture of highly redundant coding and uncoded transmission outperforms...
This paper addresses the problem of single-cell point-to-multipoint communications. We consider a base station that needs to transmit a common information to a group of users. We propose a layered Wyner-Ziv coding (WZC) scheme based on nested lattice quantization. In our scheme, we use the base layer generated by a standard coder as the decoders side information. Then, WZC is performed for quality...
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