To decode the transmit message pairs and then obtain the exclusive OR (XOR) message, this letter proposes the double-reliability-based decoding (DRB) algorithms with informed dynamic scheduling (IDS) for low-density p...
详细信息
To decode the transmit message pairs and then obtain the exclusive OR (XOR) message, this letter proposes the double-reliability-based decoding (DRB) algorithms with informed dynamic scheduling (IDS) for low-density parity-check (LDPC) coded physical-layer network coding (PNC) systems. The proposed DRB decoding with informed stability (IS-DRB) utilizes a new stability measure to determine the update order of the check nodes. Moreover, by exploiting the principle of PNC decoding, we present an improved IS-DRB (IIS-DRB) decoding to select the check node with unsatisfied PNC mapped checksum and the large stability to update first. This is due to that message propagated from this check node can quickly correct the variable node that causes unsatisfied checksum. Simulation results show that the proposed algorithms can realize significant performance improvement of about 0.5 dB over the conventional DRB decoding with the limited increase in complexity.
This letter studies a lattice-code based multi-user MIMO system. In the uplink, K single-antenna users encode their messages with the same q -ary linear code mapped to q -PAM, belonging to the ensemble of lattice code...
详细信息
This letter studies a lattice-code based multi-user MIMO system. In the uplink, K single-antenna users encode their messages with the same q -ary linear code mapped to q -PAM, belonging to the ensemble of lattice codes. The NR -antenna receiver attempts to compute K independent streams of integer-combinations (ICBs) of the users' messages. To this end, we put forth a new interference-whitening (IW) based ICB detection method, which reduces the loss of the linear filtering operation in existing integer-forcing (IF). The soft detection outputs are forwarded to K channel-code decoders to recover the messages. For practical configurations with moderate-to-large K , the proposed ICB detection exhibits an enlarged achievable mutual information and considerably improved FER performance, over existing IF.
This paper presents a novel three-time slot transmission protocol designed for energy-constrained two-way relay systems. In a departure from traditional energy sources, our approach serves a dual purpose by not only p...
详细信息
This paper presents a novel three-time slot transmission protocol designed for energy-constrained two-way relay systems. In a departure from traditional energy sources, our approach serves a dual purpose by not only providing power to the system but also significantly enhancing its security. We leverage both physical-layer network coding (PNC) and bit-level Exclusive OR (XOR) technology to amplify system capacity and bolster security. Given the unavailability of exact closed-form solutions, we utilize tight upper bounds for the signal-to-noise ratio (SNR) to derive approximate closed-form results, specifically focusing on outage and intercept performance under Rayleigh channel conditions. We also provide performance bounds for outage and intercept probabilities in the high SNR regime. Our simulation results validate the accuracy of our derived probabilities, demonstrating consistency with Monte Carlo simulations. Furthermore, our investigation reveals that the time allocation factor has minimal impact on the security and reliability of the proposed protocol, particularly under high SNR conditions. In addition, we conduct a comparative analysis between the XOR scheme introduced in this article and non-XOR (NXOR) systems. This analysis underscores the superior security-reliability tradeoff of our approach, particularly in scenarios characterized by poor channel conditions between the energy source user and potential eavesdroppers.
In this paper, we study the performance of physical-layer network coding in asymmetric two-way relay channels using four different cases having different poor channels:phase asymmetry, downlink asymmetry, uplink asymm...
详细信息
In this paper, we study the performance of physical-layer network coding in asymmetric two-way relay channels using four different cases having different poor channels:phase asymmetry, downlink asymmetry, uplink asymmetry and node asymmetry. The decision and mapping rule for symmetric and asymmetric cases are studied. The performance in terms of bit error rate for each case will be studied and analysed by computer simulation. Analytical and simulation results show that uplink asymmetry is the worst case;intra-phase asymmetry and unreliable uplink channels will more severely affect the performance degradation, which is caused by channel asymmetry.
In this paper, a bidirectional cognitive cross network using spatial modulation (SM) along with physical-layer network coding (PLNC) is proposed. In our model, a primary user pair located far from each other, exchange...
详细信息
In this paper, a bidirectional cognitive cross network using spatial modulation (SM) along with physical-layer network coding (PLNC) is proposed. In our model, a primary user pair located far from each other, exchanges information in the lack of a direct link so that a relay is required for a reliable communication. A secondary user pair shares their relay with the primary user in return for access to the licensed spectrum. Both users exploit SM while the relay also applies PLNC. It is assumed that each user pair can eavesdrop the signal of the other user pair to use these signals as side information and cancel them from the PLNC mapped signal broadcasted by the relay. Optimum power allocation, in which two scenarios are considered, is proposed for sources and the relay. In Scenario I, the optimization is performed by minimizing the bit error probability (REP) of the primary user due to its priority in the licensed band. Scenario 2, which minimizes REP of both users, provides the optimum results for the whole system. A theoretical REP analysis is performed and the results are supported via computer simulation results, which are in perfect match with theoretical findings.
Noncoherent two- and three-phase two-way relaying (TWR) techniques are bandwidth efficient and entail no pilot symbol-related rate loss. However, noncoherent two-phase TWR (2P-TWR) has not been compared with three-pha...
详细信息
Noncoherent two- and three-phase two-way relaying (TWR) techniques are bandwidth efficient and entail no pilot symbol-related rate loss. However, noncoherent two-phase TWR (2P-TWR) has not been compared with three-phase TWR (3P-TWR), and several unanswered questions remain. In this paper, we focus on the noncoherent detection of the relay with the decode-and-forward technique. For the noncoherent maximum-likelihood detector at the relay, we propose a distance measure for the transmitted signals of the two terminal nodes. For 2P-TWR, we propose that the signal constellation of one terminal node is the signal constellation of the other terminal node rotated by an angle. Using the proposed distance measure, we obtain the optimal angles and thus resolve those unanswered questions pertaining to 2P-TWR. Finally, noncoherent 3P-TWR was found to significantly outperform noncoherent 2P-TWR in simulations and distance analyses.
This paper studies a lattice-code based multiple-access (LCMA) system. In the uplink, K users encode their messages with the same 2(m)-ary ring code mapped to 2(m)-PAM, belonging to the ensemble of lattice codes. All ...
详细信息
ISBN:
(纸本)9798350310900
This paper studies a lattice-code based multiple-access (LCMA) system. In the uplink, K users encode their messages with the same 2(m)-ary ring code mapped to 2(m)-PAM, belonging to the ensemble of lattice codes. All users transmit simultaneously. The receiver attempts to compute K independent streams of integer-combinations (ICBs) of the users' messages. For this, 1) we establish and solve a new "bounded independent vectors problem" (BIVP) which identifies a near-optimal set of coefficient vectors w.r.t. the ICBs, outperforming existing LLL and HKZ lattice reduction methods;2) we put forth new LCMA soft detection algorithms, which calculate the a posteriori probability w.r.t. the ICB over the lattice. The per-user complexity is of order less than O(K), suitable for massive access of K being large. The soft detection outputs are forwarded to K ring-code decoders to recover the messages. With our developed techniques, LCMA is shown to support a significantly higher load of users and exhibits an improved frame error rate over state-of-the-art IDMA and SCMA schemes. Such advanced functionality are achieved with just parallel processing and K single-user decoding operations.
physical-layer network coding (PNC) has great potential to improve the throughput and latency in wireless networks. However, there are two main challenges in PNC systems that do not exist in the conventional Point-to-...
详细信息
ISBN:
(纸本)9781538674628
physical-layer network coding (PNC) has great potential to improve the throughput and latency in wireless networks. However, there are two main challenges in PNC systems that do not exist in the conventional Point-to-Point (P2P) communication systems: 1) time and frequency asynchrony of the paired PNC users;and 2) ambiguity of the PNC mapping at the relay node. To address these challenges, in this paper, we apply precoding for power control and phase synchronization of the paired PNC users, while we use modulo-root M addition for the PNC mapping ambiguity removal in higher-order M-ary Quadrature Amplitude Modulations (M-QAM). We evaluate the performance of the system in the framework of the Orthogonal Frequency Division Multiplexing (OFDM)-PNC systems with cyclic prefix extension under Rayleigh faded Tapped Delay Line (TDL)-C and Rician faded TDL-D channel models, proposed by the Third Generation Partnership Project (3GPP), as well as the Additive White Gaussian Noise (AWGN) channel model. The results reveal that our proposed technique can achieve a significant Signal-to-Noise Ratio (SNR) improvement of 12 dB over its asynchronous OFDM-PNC counterpart (without precoding) for Binary Phase Shift Modulation (BPSK) under a TDL-C faded channel model. Moreover, without channel coding, our proposed PNC technique requires an SNR of around 13dB to deliver a two-way 16-QAM communication at a Bit Error Rate of 10-3 under a Rayleigh faded TDL-C channel.
In this paper, we investigate collision-free transmission scheduling in data-collection-oriented underwater acoustic (UWA) networks with and without physical-layer network coding (PNC). This application-oriented netwo...
详细信息
ISBN:
(纸本)9798350332261
In this paper, we investigate collision-free transmission scheduling in data-collection-oriented underwater acoustic (UWA) networks with and without physical-layer network coding (PNC). This application-oriented network is usually deployed as a linear multi-hop topology to extend the coverage area and has a funneling effect due to the location-dependent unfairness problem. Moreover, different from terrestrial radio networks, the channel characteristics of UWA networks are featured with high propagation delay and distance-frequency-dependent attenuation. To tackle these problems, two collisionfree scheduling schemes are put forth under a linear multihop topology, which also provides local-traffic fairness among all nodes. Specifically, a successive-link-based scheduling is presented to achieve the upper bound when PNC is not available. Furthermore, PNC is introduced into the scheduling design to obtain the theoretical upper bound. Numerical simulation results indicate that successive-link-based scheduling can achieve the optimal utilization of 3/8 when PNC is not available. In contrast, PNC-aided scheduling is capable of reaching the theoretical upper bound of 1/2. Most important, the two scheduling schemes developed for linear topology are also a fundamental component that can be used in more complex network configurations.
Based on the study of the principles and the development of the networkcoding, the survey analyzes its applicable techniques in the physical-layer of the wireless communication systems and focuses on the physical-lay...
详细信息
暂无评论