Technology For Mobile Communication Systems Research Articles

Research on Beam Allocation of Millimeter Wave Massive MIMO based on Matching Game

As one of the most promising critical technologies for realizing 5G networks, mmWave communication technology has received more and more attention and research. At the same time, due to the integration and symbiosis of mmWave communication, massive MIMO, and ultra-dense network, recent organizations have also jointly proposed the rational introduction of these three technologies in mobile communication systems to improve spectrum efficiency and energy efficiency in 5G. This paper focuses on a single-cell multi-user mmWave massive MIMO system. To optimize the total data rate, we propose a beam allocation algorithm based on a one-to-one matching game under the condition that the number of RF chains is less than the number of users. The simulation results show that the proposed algorithm obtains almost the same performance as the exhaustive method on the premise that the algorithm complexity is lower than the thorough method.

ПРИМЕНЕНИЕ ТЕХНОЛОГИИ MIMO В СОВРЕМЕННЫХ СИСТЕМАХ БЕСПРОВОДНОЙ СВЯЗИ РАЗНЫХ ПОКОЛЕНИЙ

Multiple Input Multiple Output (MIMO) technology is widely used in modern IEEE radio access systems. There is a tendency to increase the number of antennas, which is also confirmed by the development of MIMO technology in mobile communication systems of 3GPP standards. Requirements for modern radio communication systems are constantly increasing. As the radio frequency spectrum becomes increasingly scarce, it becomes increasingly difficult to transmit large amounts of information by expanding the frequency channel bandwidth. Therefore, the use of MIMO technology to increase the spectral and energy efficiency of communication systems is relevant. In 5G systems, Massive MIMO technology is used, when using which the number of antennas is measured in tens and hundreds. The characteristics of various versions of MIMO technology implemented in the existing standards 802.11n, 802.11ac, 802.11ax, as well as in the promising standard 802.11be (6G systems) are described in detail. Technologies of directional transmission, spatial multiplexing, selection of antennas as particular cases of precoding are considered. Trends of MIMO technology development in wireless communication systems are shown.

SIP as a unified signalling solution in a beyond 3G system

The adoption of packet-switched technologies in mobile communication systems has enabled the provision of IP-based services to mobile users. Yet, these systems, such as the UMTS network, are not flexible enough to allow the extensive deployment of IP-oriented protocols. Furthermore, they are not able to meet the stringent QoS requirements imposed by the enhanced multimedia services that are expected to be encompassed in future mobile systems. For the aforementioned reasons, an innovative beyond 3G network architecture – denoted as SIP RAN – is presented in this paper, posing an evolution to the standard UMTS network. According to the proposed concept, the GPRS Support Nodes are integrated into a single entity and the Session Initiation Protocol is adopted for performing mobility and session management, currently undertaken by the UMTS Non-Access Stratum protocols. Both modifications to the UMTS network and protocol architecture result in the smooth evolution of the UMTS Core Network towards IP, while accomplishing considerable performance improvement. In order to evaluate the target architecture and substantiate its actual effectiveness, a series of experiments was carried out, by utilizing a fully functional emulator.