Asymmetric Data Transmission Research Articles

CGR-QV: A virtual topology DTN routing algorithm based on queue scheduling

In this paper, we proposed a CGR-QV algorithm in order to solve the problems of low message delivery rate and low throughput problems in deep space communication networks, which are caused by the high delay, asymmetric data transmission rate, and frequent topology switching characteristics. The proposed method separate different message types in the queues, establish the relationship between TTL, wait time and Hurst to prevent the phenomenon of "starvation" and redundancy. In view of the impact of congestion on the network, improved algorithm use the Elastic load balancing strategy establish the relationship between optimal thresholds α and network performance reliability. Simulation result show that the algorithm has improved in throughput as about 19%, message delivery rate improved as about 7.5% and bandwidth rejection rate decreased as about 4.7%, the algorithm can balance the impact of topology updates and resource consumption better in space communication networks.

The Distortions Region of Broadcasting Correlated Gaussians and Asymmetric Data Transmission Over a Gaussian BC

A memoryless bivariate Gaussian source is transmitted to a pair of receivers over an average-power limited bandwidth-matched Gaussian broadcast channel. Based on their observations, Receiver 1 reconstructs the first source component while Receiver 2 reconstructs the second source component both seeking to minimize the expected squared-error distortions. In addition to the source transmission digital information at a specified rate should be conveyed reliably to Receiver 1–the “stronger” receiver. Given the message rate we characterize the achievable distortions region. Specifically, there is an ${\sf SNR}$ -threshold below which Dirty Paper coding of the digital information against a linear combination of the source components is optimal. The threshold is a function of the digital information rate, the source correlation and the distortion at the “stronger” receiver. Above this threshold a Dirty Paper coding extension of the Tian-Diggavi-Shamai hybrid scheme is shown to be optimal.

Source Broadcasting and Asymmetric Data Transmission With Bandwidth Expansion

We consider the broadcasting of a scalar memoryless Gaussian source over a two-user Gaussian broadcast channel with bandwidth expansion. In concurrent with the source description, a message that should be decoded reliably just by the “higher quality” user is sent. Conditioned on the message rate, we derive a necessary condition for the achievability of a mean-squared-error distortion pair at the two receivers, which extends the Reznic–Feder–Zamir bound. This necessary condition and a sufficient condition that we derive establish the set of achievable energy-distortion exponents for this setting.

Application Research Based on 5G Wireless Communication Technology

Abstract With the continuous development of science and technology, network technology is changing from each passing day. Nowadays, smart phones and other products are gradually popularized. China’s mobile network technology is also developing rapidly. The development of communication technology has driven the development of society. Nowadays, the development of 5G wireless communication technology has greatly promoted the research of related technologies. With the advancement of the times, the number of people surfing the Internet has also increased greatly. China’s wireless communication technology will be greatly developed, and its application prospects are very broad, which has laid a great foundation for future scientific research and played a certain role. This paper further studies through the research of the core technology of 5G wireless communication technology. The core technologies of 5G wireless communication technology mainly includes wireless transmission and network architecture technology, Non-orthogonal multiple access technology, D2D communication networking, MIMO antenna technology, simultaneous co-frequency full-duplex technology, intelligent technology. With the advancement of time, 5G technology will be commercialized after 2020, which will meet the rapid development of mobile Internet services in the future and bring new experiences of users. As the research progresses, the key technologies of 5G will gradually become clear, and will enter the stage of standardization research and formulation in the next few years. 5G communication technology is the most advanced mobile communication technology. Compared with 4G communication technology, it is more than ten times faster than its data transmission speed, and has a significant advantage in fast transmission rate. From the practical application of 5G communication technology, the transmission speed can be guaranteed in the case of 28 GHz band 1Gbpses, and the transmission speed of 4G communication technology under the same conditions can only reach about 73Mbps, and the asymmetric data transmission capability is only higher than 3Mb/s. It can be seen that 5G communication technology achieves a significant increase in transmission speed.

An End-To-End Rate Control Protocol for Intermittently Connected Networks

In this study, we propose a rate control algorithm for intermittently connected networks (ICNs), a type of delay/disruption-tolerant network. The different characteristics of ICNs compared with traditional TCP/IP networks lead to problems that do not occur in legacy networks, such as network partitioning, long and varying delays, high loss probability, and asymmetric data transmission rates. To overcome these issues, much recent research has been carried out. However, while the results have helped achieve smooth communication between nodes, there are still certain shortcomings. For example, if many messages are input by the nodes in a network, these schemes do not work well. To resolve this problem, we propose a novel sending rate control algorithm in an additive increase/multiplicative decrease manner. To detect network congestion, we measure the receiving rate, one-way delay, and average number of copies. When the measured receiving rate increases, the congestion window (cwnd) also increases; otherwise, cwnd decreases. The simulations show that the proposed algorithm can adjust the sending rate of nodes to avoid network congestion and provide a fair share of the network for the nodes.

A comparison of frequency-division systems to code-division systems in overloaded channels

In this paper, a frequency-division counterpart of joint power control and sequence design problem for code- division multiple-access (CDMA) systems is solved. Total transmit and receive power minimizations are considered for frequency- division multiplexing (FDM) and frequency-division multiple- access (FDMA) communications over overloaded channels. After the definition of channel overloading for CDMA systems is extended to the frequency-division systems, the user admissibility is characterized by a necessary and sufficient condition for the existence of the optimal solution under unequal signal-to- interference-plus-noise ratio constraints at the output of linear receivers and asymmetric data transmission rate constraints among users. The optimal signal power, bandwidth, transmit waveform, and receive waveform are derived for each user as the decision parameters of the optimization problem. It is shown that, if this solution is applied for the uplink users to minimize the total receive power, the optimal FDMA system performs the same as the optimal CDMA system. It is also shown that, if this solution is applied for the downlink users to minimize the total transmit power, the optimal FDM system always outperforms the code-division system that minimizes the extended total squared correlation. Numerical results suggest that the optimal FDM system and the optimal downlink code-division system achieve the same performance when the total transmit power is minimized.

Processing Acceleration of Broadband Wireless MAC in a Portable Terminal

Among the broadband wireless communication standards utilized to satisfy the demand for multimedia services, time division duplexing (TDD) is satisfactory for the asymmetric data transmission emphasized in Internet services. In this system, the transition between receiving a frame and transmitting a response must be bounded for an effective use of radio resources. However, the minimized inter-frame space-time requires high processing power. The aim of the present paper is to gain insight into the time latency at the turn-around time of a TDD operation. We also propose a simplified new processor, which is a terminal device-friendly architecture that includes prediction and preparation to support processing of burst-type traffic.

Systems considerations for the use of xDSL technology for data access

A variety of signal processing techniques have been developed over the past 10 years to increase the bit rate of digital transmission through telephone loop twisted pairs. The ISDN basic rate access 2B1Q digital subscriber line (DSL) was the first technology of this type to be deployed commercially at 160 kb/s full-duplex transmission on a single twisted pair. Other transmitter/receiver circuits have been developed over the years that support symmetric and asymmetric data transmission from several hundreds of kilobits per second to several megabits per second using the 2B1Q line code in the case of HDSL and various modulation techniques (QAM, CAP, and DMT) in the case of ADSL. These more recent forms of xDSL circuitry have begun to be used to provide commercial Internet access. This article analyzes the system level considerations for using these technologies in the increasing complex loop network of telephone companies. A "next generation" of xDSL access system is proposed, and the requirements for such a system are discussed.