Performance of multi-antenna wireless systems based on time reversal

5G wireless mobile communication system is faced with massive equipment access, information security and effective transmission is worth paying attention to. Wireless physical layer security mainly uses encryption principle to enhance the security of information transmission, while time reversal technology combines its electromagnetic characteristics and physical channel characteristics to improve the security performance of wireless communication system. In this paper, a signal transmission model of wireless multi-antenna communication system based on time reversal cavity is proposed and white Gaussian noise is introduced. The simulation results show that the space-time focusing characteristics of time reversal cavity can make the signal energy more concentrated on the target user, which can not only effectively alleviate the communication quality problems caused by multipath effect, but also ensure the security of information transmission process.

Energy-Saving D2D Wireless Networking Based on ACO and AIA Fusion Algorithm

Lower energy consumption and higher data rate have been becoming the key factors of modern wireless mobile communication for the improvement of user experiences. At present, the commercialization of 5G communications is gradually promoting the development of Internet of things (IoT) techniques. Due to the limited coverage capability of direct wireless communications, the indirect device-to-device (D2D) communications using information relay, in addition to the single 5G base station deployment, have been introduced. Along with the increase of information nodes, the relay devices have to undertake the nonnegligible extra data traffic. In order to adjust and optimize the information routing in D2D services, we present an algorithmic investigation referring to the ant colony optimization (ACO) algorithm and the artificial immune algorithm (AIA). By analyzing the characteristics of these algorithms, we propose a combined algorithm that enables the improved the iterative convergence speed and the calculation robustness of routing path determination. Meanwhile, the D2D optimization pursuing energy saving is numerically demonstrated to be improved than the original algorithms. Based on the simulation results under a typical architecture of 5G cellular network including various information nodes (devices), we show that the algorithmic optimization of D2D routing is potentially valid for the realization of primitive wireless IoT networks.

Enchancement of GSC Using OFDM and QAM Over Reiyleign Fading Channel: A Review

As indispensable as communication has been to human endeavors, geographical and physical distance would have been a barrier to its effective deployment if not for the advent of wireless mobile communication. In the world today, most of the developments we see in all spheres of our modern life are influenced by communication technologies. However, the performance of each modulation scheme deployed in the communication system dictates the Quality of Service (QoS), effective cost management, efficient power, available bandwidth, Bit Error Rate (BER), and Signal to Noise Ratio (SNR). Extensive research has been done with different authors proffering wide ranging solutions for generalized selection combining (GSC) algorithms in the presence of noise and interfering signals. Some of the reported approaches include varying modulation schemes, changing the channel, and using different equalizing techniques. Many of these proposed solutions worked effectively in some areas while they understandably left other areas untouched, others show better performance by analyzing the channel using; Log-likelihood Ratio (LLR), integral expression, and multiple-mode transmission scheme which in turns proof to be of better performance with a good result. Despite all the efforts, overcoming the issue of noise interference in the communication channel has still been somewhat elusive. Conclusively, to reduce noise to the barest minimum in mobile/cellular communication, this review proposes modulation scheme synchronization with combined diversity technique over an improved channel that is less prone to noise.

Potential key challenges for terahertz communication systems

The vision of 6G communications is an improved performance of the data rate and latency limitations and permit ubiquitous connectivity. In addition, 6G communications will adopt a novel strategy. Terahertz (THz) waves will characterize 6G networks, due to 6G will integrate terrestrial wireless mobile communication, geostationary and medium and low orbit satellite communication and short distance direct communication technologies, as well as integrate communication, computing, and navigation. This study discusses the key challenges of THz waves, including path losses which is considered the main challenge; transceiver architectures and THz signal generators; environment of THz with network architecture and 3D communications; finally, Safety and health issues.

Multiobjective Multicast DSR Algorithm for Routing in Mobile Networks with Cost, Delay, and Hop Count

Tremendous evaluation of wireless mobile communication needs more efficient algorithms for communication systems. The use of conventional single-objective optimization algorithms may be unsuitable for real applications, because they act to the detriment of the rest of the performance parameters like lifetime network, delay, cost, and hop count; for this reason, multiobjective is needed. This paper presents performance evaluation and compares between the Multicast MDSR and MAODV with MACO. The proposed MDSR is concerned with change of the route discovery phase, where the route selection is based on the shortest path of route reply packets on the route with calculating the number of hop counts. Also, this article compares our MDSR modification with the evaluation algorithm based on Ant Colony Optimization (ACO), which finds the best path and multicast tree optimizes total weight (cost, delay, and hop count) of the multicast tree using multiobjective. Experimental results proved that the proposed MDSR algorithm is more efficient than MAODV and MACO in the total weight (cost, delay, and hop count), respectively. Moreover, the MACO outperforms MAODV for multicast routing problem.

Moving Ad Hoc Networks—A Comparative Study

An ad hoc network is a wireless mobile communication network composed of a group of mobile nodes with wireless transceivers. It does not rely on preset infrastructure and is established temporarily. The mobile nodes of the network use their own wireless transceivers to exchange information; when the information is not within the communication range, other intermediate nodes can be used to relay to achieve communication. They can be widely used in environments that cannot be supported by wired networks or which require communication temporarily, such as military applications, sensor networks, rescue and disaster relief, and emergency response. In MANET, each node acts as a host and as a router, and the nodes are linked through wireless channels in the network. One of the scenarios of MANET is VANET; VANET is supported by several types of fixed infrastructure. Due to its limitations, this infrastructure can support some VANET services and provide fixed network access. FANET is a subset of VANET. SANET is one of the common types of ad hoc networks. This paper could serve as a guide and reference so that readers have a comprehensive and general understanding of wireless ad hoc networks and their routing protocols at a macro level with a lot of good, related papers for reference. However, this is the first paper that discusses the popular types of ad hoc networks along with comparisons and simulation tools for Ad Hoc Networks.

Analysis of 5G Non-Orthogonal Technology Application on Smart Grid

Fifth generation (5G) wireless communication networks are being deployed worldwide at present, which not only enhances transmission ability with wide bandwidth for wireless mobile communication, but also enables 5G to promote a new digital, network and intelligence for all industry. Power communication has unique requirement and feature for itself, and with more and more power and other energy terminal devices need to access network, the current air access technology is difficult to satisfy the requirements. The 5G had carried out many key technology researches, including air interface and network technology, which establish solid basement for 5G standard and 5G+industry application. The article focuses on 5G Non-Orthogonal Multiple-Access (NOMA) technology, especially PDMA, and illustrates technology application scheme with power collection requirement as an example. It can be seen that NOMA can enhance network capability greatly for power communication, and improve transmission cover ability.