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In many communication networks, the availability of channel state information at various nodes provides an opportunity for network nodes to work together, or “cooperate.” This work studies the benefit of cooperation in the multiple access channel with a cooperation facilitator, distributed state information at the encoders, and full state information available at the decoder. Under various causality...
Robust linear analog block coding of a correlated Gaussian source over a Rayleigh fading channel, without encoderside channel-state information (CSI) is investigated. The encoder which minimizes the minimum mean square error, averaged over an ensemble of decoders whose channel gains are drawn from an exponential distribution is derived. This encoder does not require CSI. It is compared with a CSI-adaptive,...
Recently, a new paradigm of multiple access (MAC) along with one eavesdropper to achieve secrecy transmissions has been getting in focus. However, all existing work on such multiple access wiretap channel (MAC-WT) mainly concentrates on the secrecy performance of the system as a whole from an information theoretic perspective. In this work, we investigate the secrecy performance of a single transmitter...
Network coding-based caching at base stations (BSs) is a promising caching approach to support massive content delivery over wireless networks. However, existing network coding-based caching designs do not fully explore and exploit the potential advantages. In this paper, we consider the analysis and optimization of a random linear network coding-based caching design in large-scale successive interference...
Machine-to-machine (M2M) communications play an important role for applications that involve connections between a massive number of heterogeneous devices in home and industrial networks. For M2M networks, realizing low latency and high reliability is of great importance. In this paper, we show the great potential of polar-coded orthogonal frequency-division multiplexing (OFDM) to fulfill those requirements...
In this paper, we consider automatic repeat request based multihop communication between a source and a destination. We present the design of near-optimal power control policies which minimize the packet drop probability (PDP), when the energy cost to receive and decode a packet is non-negligible. The design problem is a nonconvex mixed integer nonlinear program, which, in general, is NP-hard to solve...
Uplink grant-free non-orthogonal multiple access (NOMA) is promising for machine-to-machine (M2M) communications to meet the requirement of sporadic short packets transmission of massive devices. In this paper, successive interference cancellation (SIC) and joint decoding (JD), as two well-known decoding techniques for NOMA, are analyzed for M2M random access. Due to the sporadic small packet transmission,...
In this paper, a new spectrum sharing model referred to as riding on the primary (RoP) is proposed for wireless- powered IoT devices with ambient backscatter communication capabilities. The key idea of RoP is that the secondary transmitter harvests energy from the primary signal, then modulates its information bits to the primary signal, and reflects the modulated signal to the secondary receiver...
In this paper, we consider the design of multi-resolution non-coherent multiple-input multiple-output (MIMO) systems that enable Unequal Error Protection (UEP). A method for designing multi-layer non-coherent Grassmannian constellations is introduced. Specifically, the proposed method yields multi-layer constellations that are amenable to a natural set partitioning strategy. The resulting subsets...
Analog network coding (ANC) is a throughput increasing technique for the two-way relay channel (TWRC) whereby two end nodes transmit simultaneously to a relay at the same time and band, followed by the relay broadcasting the received sum of signals to the end nodes. Coherent reception under ANC is challenging due to requiring oscillator synchronization for all nodes, a problem further exacerbated...
In this paper, the secrecy outage performance of an underlay cognitive decode-and-forward (DF) relay network over independent and non-identical distributed (i.n.i.d) Nakagami-m fading channels is investigated, in which the secondary user transmitter communicates with the secondary destination via relays, and an eavesdropper attempts to overhear the information. We assume that the channel state information...
In this paper, we propose new Raptor codes suitable for uplink Internet of Things using single carrier transmission technique (SC-IoT) with low density parity check (LDPC) codes as the precode, called LDPC-Raptor codes. The utilization of LDPC as the precode is to guarantee high capability of error correction for better Raptor codes performance while keeping the computational complexity low. Raptor...
We consider an energy harvesting (EH) based cooperative relaying network, where two half-duplex relays can alternatively forward source data to the destination. The power-splitting technique is implemented at each relay. That is, part of the received source signal and inter-relay interference is allocated for the EH, while the remaining part is used for the information decoding (ID). The inter-relay...
This paper presents a low-complexity approach for calculating soft decision metrics of polar coded quadrature amplitude modulation (QAM) system. A simple and general bit log likelihood ratio (LLR) expression is provided for Gray coded QAM signals. The characteristics of Gray code mapping such as symmetries and repeated formats of the bit assignment in a symbol among bit groups, are exploited effectively...
A cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) system that transmits information over a time-varying fading channel is considered. In channels with large Doppler spreads, the frequency orthogonality assumption of OFDM is not valid. Hence, inter-carrier interference (ICI) is introduced, which leads to higher bit error rates (BERs). We propose a channel equalizer based on the BCJR...
The performance of lattice coding and decoding for the ergodic fading point-to-point channel is studied in the presence of channel estimation errors at the receiver. We show that lattice codes achieve rates within a constant gap to that of Medard's scheme with Gaussian input. Interestingly, the gap does not depend on the channel estimation error variance nor the signal-to-noise ratio (SNR), for a...
In this paper we obtain capacity region for discrete memoryless 2-receiver less noisy broadcast channel when channel state is known only at the receivers, then; this region is possibly extended to discrete time and continuous alphabet fading Gaussian 2-receiver less noisy broadcast channel and ergodic capacity of this fading channel is obtained.
This paper considers communication over the point-to-point Gaussian channel with stationary and ergodic channel gain and full channel state information. The capacity of this channel can be achieved in a straightforward manner via any capacity-achieving codebook for the non-fading Gaussian channel, in conjunction with separable coding, i.e., coding independently over each fading state. Despite its...
Interleave division multiple access (IDMA) is a kind of multiple access technique which employs chip-level user-specific interleavers to separate each user's data from the superimposed signal of all users. Pilot-assisted channel estimation for IDMA and pilot-assisted timing tracking for IDMA have been respectively reported in the literature. In this paper, we propose a joint estimation of timing tracking...
In this paper, we propose a new baseband architecture for Internet of Things (IoT) terminals that support long range communications such as those based on Orthogonal Frequency-Division Multiple Access (OFDMA) and spread spectrum technologies. We analyze the workload profiles of both systems and find that the frame detection unit has by far the highest computational load. Based on this analysis, we...
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