Multiple Physical Layer Research Articles

Transmission of Physical Layer Network Coding Based on Massive MIMO over Millimeter Wave Channel

Massive Multiple Input Multiple Output system and physical layer network coding (PNC) are two important technologies that are considered in new generation networks. In this paper we investigate the effect of increasing the number of antenna elements at user nodes and relay node in the presence of PNC. Two-way wireless relay transmission is considered in conjunction with massive number of antennas at the relay node assuming millimeter wave (mmWave) band channel environment. End-to-end transmission is considered using 3-D QUAsi Deterministic RadIo channel GenerAtor (QuaDRiGa) channel model. The performance measures used are the bit error rate (BER) and throughput. Up to 100% increase in throughput of PNC coded system is obtained. The BER performance is improved only when the number of relay node antennas is much higher than that of the user node. Combining mMIMO with PNC gives better throughput without affecting the BER at high SNR. This is achieved with reasonable number of antennas at the user nodes.

Secure transmission for cooperative NOMA systems with source‐relay selection

Both cooperative non-orthogonal multiple access (NOMA) and physical layer security (PLS) are promising techniques for future communication systems. This paper investigates the PLS performance of a cooperative NOMA system where multiple sources transmit a superposed message to two users by utilizing either amplify-and-forward (AF) or decode-and-forward (DF) relays in both non-colluding and colluding eavesdropper scenarios. A source-relay selection scheme is proposed for this system aiming at improving the secrecy performance. Additionally, the closed-form expression of the secrecy outage probability (SOP) is derived for the proposed source-relay selection schemes. It is demonstrated that in the proposed schemes, the theoretical results match well with the simulation results. In addition, the proposed schemes outperform the conventional OMA system in terms of SOP.

Capacity Analysis and Improvement of LDM-Based Multiple-PLP Configurations in ATSC 3.0

This article analyzes the capacities of various layered-division multiplexing (LDM)-based multiple physical layer pipe (M-PLP) configurations in Advanced Television Systems Committee (ATSC) 3.0. Further, this article proposes an extended multi-layer LDM that consists of a core layer and one or more enhanced layer(s) combined with different injection levels. The proposed multi-layer LDM can be combined with time-division multiplexing (TDM) and/or frequency division multiplexing (FDM) to multiplex more than two PLPs. This article provides the structures of a transmitter and receiver for the multi-layer LDM and various M-PLP configurations based on the proposed multi-layer LDM. In addition, by extending to a multi-layer LDM, the low rate low-density parity-check (LDPC) codes are proposed to improve the transmission efficiency of an extremely robust service with lower data rate, such as robust audio, in the core layer of the multi-layer LDM. Simulation results show that the M-PLP configurations based on more than two layers can obtain the improved reception performance compared to the M-PLP configurations based on only two layers supported by the PHY standard in ATSC 3.0. However, since the performance degradation of layered time-division multiplexing (LTDM) with fewer layers is not significant compared to multi-layer LDM, LTDM can be a good solution to efficiently transmit M-PLPs.

A channel estimation method for wireless communication in HPLC&RF dual mode system

With application of high-speed power line carrier communication (HPLC), some problems are emerging such as network outliers, low success rate of power outage reporting and short single hop communication distance. Wireless communication (RF) can effectively solve these problems and thus become an effective complement to HPLC. For OFDM based wireless communication in HPLC&RF dual mode system, a channel estimation method is proposed. Compared with LTF-based and pilot-based channel estimation methods applicable to cases with few and multiple physical layer load symbols respectively, the proposed method can be applied in all cases. When the number of symbols is small, it outperforms pilot-based method by 2~3 dB and is still better than LTF-based method. When the number of symbols is large, it outperforms LTF-based method by 2~5 dB and still better than pilot-based method.

Online Learning Aided Adaptive Multiple Attribute-Based Physical Layer Authentication in Dynamic Environments

Exploiting physical (PHY)-layer characteristics for authentication has great potential to provision underlying trust for low-ended Internet of things (IoT) devices with limited computation resources. In this paper, we propose an online learning aided adaptive PHY-layer authentication framework for enhanced authenticity provisioning. Instead of relying on some preset PHY-layer signatures with scenario-sensitive “thresholds,” multiple PHY-layer attributes are jointly considered by the proposed scheme to improve the reliability and robustness of PHY-layer authentication. Such a dimension extension on PHY-layer signatures can effectively deteriorate the spoofing capability of malicious attackers. However, it also complicates the predicting and authenticating procedure of the legitimate receiver. Therefore, artificial intelligence aided search algorithms are formulated to facilitate adaptive selection of the Most Effective PHY-layer Attributes (MEA) through learning their historical authenticity performance. To be specific, the attributes which are predicted to be effective in maximizing the authentication capability, in terms of low false alarm rate and low miss detection rate, will be dynamically selected by the authenticator in an autonomous manner. Theoretical analysis shows that the proposed learning algorithm achieves asymptotically diminishing regret. Moreover, extensive experiments are conducted using Universal Software Radio Peripherals (USRPs) in a laboratory environment, which further validates the efficiency of the proposed scheme.

Fuzzy Learning for Multi-Dimensional Adaptive Physical Layer Authentication: A Compact and Robust Approach

The performance of physical layer authentication schemes strongly suffers from the uncertainties and dynamics of communications, which are mainly caused by the time-varying channels with unpredictable interference conditions. In this paper, we propose a multi-dimensional adaptive physical layer authentication scheme to achieve reliable authentication performance in time-varying environments. First of all, the fuzzy theory is explored for modeling multiple physical layer attributes with imperfectness and uncertainties. The designed fuzzy theory-based model is a parametric method that requires less observed samples of the utilized attributes together with less authentication system parameters to be determined compared with the nonparametric methods, demonstrating a compact authentication model. By deriving the false alarm rate and misdetection rate of the designed model, a hybrid learning-based adaptive authentication algorithm is proposed to near-instantaneously update system parameters, thereafter to adapt to the time-varying environment. Hence, our scheme is applicable to the communication environment with uncertainties and dynamics, resulting in a robust authentication scheme. Simulation results show that our solution can significantly improve the authentication performance in the time-varying environment. Compared with some exiting schemes, i.e., the optimal weights-based scheme and neural network-based scheme, our scheme achieves much better authentication performance.

Regional Contents in a National DVB-T2 SFN: A Novel Approach Based on DVB-SIS

To include regional contents in a national single-frequency network (SFN), the RAI Radiotelevisione Italiana has studied and tested a system configuration that benefits from the multiple physical layer pipes (PLPs) of Digital Video Broadcasting-Second Generation Terrestrial (DVB-T2) standard in a laboratory. According to the proposed solution, in each region, the national programs are transmitted in one PLP, whereas other k PLPs convey the regional contents of a macroregional SFN, formed by a region and the (k–1) surrounding ones. The DVB Single Illumination System standard can be a valid technical solution to distribute such complex signals to SFN transmitters via satellite or terrestrial contribution links in a cost-effective way. This article presents the rules adopted to map content into DVB-T2 PLPs and their application to the Italian case. Furthermore, it describes the end-to-end laboratory setup and the results of tests carried out, showing that a national SFN can broadcast both national and regional contents with high flexibility and spectrum efficiency.

Multiple Eavesdropper-Based Physical Layer Security in SIMO System With Antenna Correlation

In this paper, we investigate the impact of antenna correlation on secure transmission in a multi-eavesdropper single-input multiple-output (SIMO) system, where the receiver and eavesdroppers are equipped with correlated antennas. Based on the practical passive eavesdropping system, the new closed-form expressions of secrecy outage probability (SOP) and non-zero secrecy capacity probability are derived to explore the effect of antenna correlation on the system with multiple eavesdroppers. To further analyze the secrecy performance of the investigated system, we theoretically derive the expression of asymptotic SOP to clearly show the diversity order and array gain. Finally, Monte Carlo simulations verify the effectiveness of our theoretical results.

Layered Division Multiplexing for ATSC 3.0: Implementation and Memory Use Aspects

This paper presents implementation and memory use aspects for layered division multiplexing (LDM) technology defined in the next generation terrestrial broadcast standard, called advanced television systems committee (ATSC) 3.0. As LDM becomes a new method that combines multiple broadcast contents, its practical considerations on transmitter and receiver implementations as well as memory usages are described in this paper. When multiple physical layer pipes are used, the feasibility of the implementation and memory use aspects are discussed, and the performance analysis in comparison with other multiplexing techniques that ATSC 3.0 offers is shown.

Single or Multiple Frames Content Delivery for Next-Generation Networks?

This paper addresses the four enabling technologies, namely multi-user sparse code multiple access (SCMA), content caching, energy harvesting, and physical layer security for proposing an energy and spectral efficient resource allocation algorithm for the access and backhaul links in heterogeneous cellular networks. Although each of the above mentioned issues could be a topic of research, in a real situation, we would face a complicated scenario where they should be considered jointly, and hence, our target is to consider these technologies jointly in a unified framework. Moreover, we propose two novel content delivery scenarios: 1) single frame content delivery (SFCD), and 2) multiple frames content delivery (MFCD), where the time duration of serving user requests is divided into several frames. In the first scenario, the requested content by each user is served over one frame. However, in the second scenario, the requested content by each user can be delivered over several frames. We formulate the resource allocation for the proposed scenarios as optimization problems where our main aim is to maximize the energy efficiency of access links subject to the transmit power and rate constraints of access and backhaul links, caching and energy harvesting constraints, and SCMA codebook allocation limitations. Due to the practical limitations, we assume that the channel state information values between eavesdroppers and base stations are uncertain and design the network for the worst case scenario. Since the corresponding optimization problems are mixed integer non-linear and nonconvex programming, NP-hard, and intractable, we propose an iterative algorithm based on the well-known alternate and successive convex approximation methods. In addition, the proposed algorithms are studied from the computational complexity, convergence, and performance perspectives. Moreover, the proposed caching scheme outperforms the existing traditional caching schemes like random caching and most popular caching. We also study the effect of joint and disjoint considerations of enabling technologies for the performance of next-generation networks. On the one hand, our proposed caching strategy increases slightly the computational complexity by 3%, 1.1%, and 2% compared to no caching, SFCD, and disjoint solution, respectively. On the other hand, the proposed caching scheme achieves a performance gain of 43%, 9.4%, and 51.3% compared to the three state-of-the-art schemes.

Performance of uncoordinated coexistence mechanisms in adhoc networks

Dynamic spectrum sharing between uncoordinated devices is impaired by interference. Simple coexistence mechanism can reduce this interference and improve network performance. We analyze performance of some simple coexistence mechanisms in detail, where the decision to transmit a packet by a given device to its intended receiver is taken solely by the transmitter receiver pair without any central control. Accurate interference models are developed assuming a large number of transmitter-receiver pairs that are randomly distributed according to a Poisson spatial point process. These are used to derive accurate expressions for packet error rates in the case of direct sequence code division multiple access physical layer model and slotted packet transmission schemes. These results are then used to study the performance of the coexistence mechanisms and compare them with each other.

Multi-channel-based scheduling for overlay inband device-to-device communications

In this paper, we consider the problem of distributed scheduling for overlay inband device-to-device (D2D) communication systems that employ an orthogonal frequency division multiple access physical layer technology. To improve the spatial reuse gain, we propose a multi-channel-based scheduling algorithm that divides the overall radio resource dedicated to D2D communication into multiple data channels and schedules the links allocated to each channel based on a signal-to-interference-aware priority-based scheduling method. Further, we develop a cross-layer queueing model to analyze the medium-access-control layer performance of the proposed scheduling algorithm and compare the analytic results with the simulation results. We demonstrate that the proposed scheduling algorithm outperforms the existing single one-channel-based algorithm to provide lower packet dropping probability, higher spectral efficiency, and lower packet delay.

Results of the DVB-T2 Field Trial in Germany

The second generation digital video broadcasting system for terrestrial broadcasting (DVB-T2) was designed using a toolbox concept. Compared with its predecessor DVB-T, the new standard introduces many new algorithms and allows for a more flexible parameter configuration. The parameters can be perfectly optimized for each reception scenario, ranging from stationary reception with roof-top aerials, up to portable or mobile reception. However, all countries that have already introduced DVB-T2 mainly focus on stationary reception. In contrast, stationary reception is no relevant option for a potential introduction of DVB-T2 in Germany. Instead, a potential roll-out would focus on the benefits of terrestrial broadcasting compared to satellite and cable, i.e., mobility. Within an extensive field trial in northern Germany, the performance of the different parameter configurations and new algorithms offered by DVB-T2 were analyzed in detail, e.g., multiple physical layer pipes, rotated constellations, and multiple-input single-output. This paper presents the trial network and the obtained measurement results, which are based on thousands of individual measurements. Moreover, the document gives recommendations for an optimal parameter configuration.

A performance study of DVB-T2 and DVB-T2-Lite for mobile reception

The DVB-T2 system is an OFDM-based broadcasting standard used not only for stationary reception, but also for mobile applications. With respect to DVB-T, DVB-T2 improves the reception quality by using a more powerful channel coding, a sophisticated time interleaver, and several innovative algorithms, such as the multiple physical layer pipes transmission mode. In 2011, a simplified profile, known as DVB-T2-Lite, has been defined in order to reduce the implementation complexity and the energy consumption in mobile terminals. In this paper, we investigate the performance of DVB-T2 and DVB-T2-Lite for mobile receivers, assuming the TU6 mobile channel. Our investigation shows that the use of sub-slicing and inter-frame interleaving yields a performance improvement for both DVB-T2 and DVB-T2-Lite, at the expense of increased decoding latency. We also illustrate that the performance advantage of inter-frame interleaving is significant, especially at low mobile speeds. Besides, at very high speeds, DVB-T2-Lite with lower code rates is able to outperform DVB-T2.

Algorithm Optimization of Resources Scheduling Based on Cloud Computing

In some service areas, such as cloud computing of virtual technology, the specific virtual technology’s level configuration processing power is limited and it has defects. [1] Under normal circumstances, the traditional cloud computing resource sharing configuration can not be effectively applied, for it has a time difference and several machines can not be connected to the network by a broadband link and work simultaneously, making the virtual technology particularly difficult in the efficiency and effectiveness of the implementation. This paper presents a cloud computing of ant colony and genetic combination of resources virtual scheduling optimization, which is applied to multiple machines physical layer simultaneously, at the same time it can optimize the allocation of resources to maximization. Experimental results show that the model algorithm is more convergent and more practical than traditional methods.

Performance of MIMO-WCDMA Multicellular Networks with Ideal Power Control

The goal of the study presented in this paper is to investigate the performance of a multiple input multiple output network using the wideband code division multiple access physical layer protocol. In this context, several transmission techniques are evaluated by executing independent Monte Carlo simulations in parallel with the help of a developed hybrid system–link level simulator. Moreover, the performance of a proposed technique that is based on the maximization of the desired signal of a Mobile Station (MS) to the total amount of interference caused to the rest of the network is evaluated as well. As results indicate, this technique can achieve up to 45 % transmission power gain for high data rate services compared to the case where only the maximization of the desired MS's signal is considered.

IEEE 802.11 DoS attack detection and mitigation utilizing Cross Layer Design

Denial of Service (DoS) attack is a powerful attack that disrupts the network and deprives the legitimate users from utilizing the network resources. DoS attacks could be implemented to target any layer of the Open Systems Interconnection (OSI) layers, in this paper we are focusing on DoS attacks that target the Medium Access Control (MAC) layer in wireless networks. We present a complete solution using Cross Layer Design techniques to detect and identify the attackers and to mitigate the attack by minimizing the negative impact on the network. DoS attacks could range from plain attacks which do not require any protocol modifications or intelligence during the attack like the signal jamming attack to sophisticated attacks where the attacker is intelligent and aware of its surroundings and constantly modifying its behavior during the attack to appear as a legitimate node to avoid detection. In this paper we are focusing on the sophisticated DoS attack in wireless networks using IEEE 802.11 Distributed Coordination Function (DCF) protocols [1–3], where the attacker is striving to appear as a legitimate member of the network and fully joined the network group and possesses for instance the spread sequence or the channel coding scheme. The algorithm is examined in fixed and mobile environments with multiple Physical (PHY) layer technologies (DSSS, FHSS, and OFDM) using different MAC layer protocols (IEEE 802.11, IEEE 802.11b, and IEEE 802.11g). DoS attackers illegally alter the IEEE 802.11 DCF standards and modify the MAC firmware code in the Network Interface Card (NIC) on their communication equipment to capture the channel by maximizing the packet transmission success rate to a degree where all other legitimate node will have near zero percent success rate for their packet transmissions. This type of DoS attack generally results in bandwidth starvation and extreme power and CPU processing consumption to the legitimate nodes in the network. Two-dimensional Markov Chain is modeled to obtain the maximum throughput to identify the DoS attackers and the rest of the presented algorithm mitigates the impact of the attackers while deceiving the attackers and make them falsely believe that the attacks are still disrupting the network so they do not resort to modifying the attacking techniques. The algorithm is validated using network simulations under different condition using different technologies.

A dynamic radio resource management scheme for the IEEE 802.16 band‐adaptive modulation and coding mode with proportional rate constraints

ABSTRACTIn this paper, we consider the problem of downlink resource allocation in the IEEE 802.16 standard based on the orthogonal frequency‐division multiple access physical layer. The objective is to allocate the downlink frequency‐time slots and transmission power to different users such that the total throughput is maximized. The allocation is subject to constraints on the total transmission power and satisfying the quality of service requirements of different users expressed in terms of proportional rates. A three‐step heuristic scheme that incorporates a linear programming technique is proposed. The problem is modelled as an unbalanced transportation problem that is solved to obtain the users' slot assignment. The Vogel approximation method is used to efficiently solve the transportation problem with a slight degradation relative to the optimal solution. The Vogel approximation method gain is shown by replacing it in the three‐step heuristic by simple round‐robin or greedy slot assignment. In terms of total throughput and fairness, it is shown that the proposed scheme is a good compromise between the greedy‐oriented schemes, which aspire to maximize the total system throughput but sacrificing fairness, and a proportional rate constraints scheme introduced in the literature that achieved short‐term fairness but penalizes the total throughput. The study also shows that the proposed scheme consumes a fraction of the time needed by the proportional rate constraints scheme. Copyright © 2011 John Wiley & Sons, Ltd.

Optimal and Successive Approaches to Signal Design for Multiple Antenna Physical Layer Multicasting

In modern wireless communications, systems that send a common information stream (called multicasting systems) are widely needed for distributing content such as television or radio. In this paper, the multiple antenna physical layer multicasting channel is considered, in which a common message is simultaneously transmitted to multiple single-antenna users. To achieve the capacity of this multicasting set-up, the covariance matrix of the transmit signal vector needs to be determined to maximize the smallest maximum achievable rate among all the users. In this paper, we develop a simple successive algorithm to determine the covariance matrix of the signal vector under the assumption that channel state information (CSI) is perfectly available at the transmitter. We first characterize properties of the capacity achieving covariance matrix and derive a closed-form expression for the matrix in the two-user case. We then derive a closed-form expression for the rate maximizing beamformer in the case of two users and propose a successive beamforming algorithm that generates the beamforming vector with low computational complexity. In the proposed precoding design scheme, the covariance matrix is successively constructed by orthogonalizing the subspace spanned by each user's channel vector until the maximum number of recursions (which is the same as the minimum of the number of transmit antennas and the number of users) is reached. The achievable rate of the proposed scheme is compared with the capacity of optimal transmission, transmit beamforming, antenna subset selection, and open-loop transmission which does not require CSI at the transmitter. As the number of users and/or antennas grows large, it is shown that the average achievable rate of the proposed scheme achieves the same average achievable rate scaling as the true capacity while reducing the computational complexity.

Hybrid Unified-Slot Access Protocol for Wireless Body Area Networks

Wireless body area network (WBAN) solution is an emerging new technology to resolve the small area connection issues around human body, especially for the medical applications. Based on the integrated superframe structure of IEEE 802.15.4, a modified medium access control (MAC) protocol, named Hybrid Unified-slot Access (HUA) protocol for WBANs is proposed with focus on the simplicity, dependability and power efficiency. Considering the support to multiple physical layer (PHY) technologies including ultra-wide band (UWB), the slotted ALOHA is employed in the contention access period (CAP) to request the slot allocation. Mini-slot method is designed to enhance the efficiency of the contention. Moreover, sufficient slot allocation in the contention-free period (CFP) makes HUA adaptive to the different traffic including the medical and non-medical applications. Simulation results show that the protocol effectively decreases the probability of collision in a CAP and extends the CFP slots to support more traffic with quality of service (QoS) guarantee.