Massive MIMO (also known as the “Large-Scale Antenna System”) enables a significant reduction of latency on the air interface with the use of a large excess of service-antennas over active terminals and time division duplex operation. For large-scale MIMO, several technical issues need to be addressed (e.g., pilot pattern design and low-antenna power transmission design) and theoretically addressed (e.g., channel estimation and power allocation schemes). In this paper, we analyze the ergodic spectral efficiency upper bound of a large-scale MIMO, and the key technologies including channel uplink detection. We also present new approaches for detection and power allocation. Assuming arbitrary antenna correlation and user distributions, we derive approximations of achievable rates with linear detection techniques, namely zero forcing, maximum ratio combining, minimum mean squared error (MMSE) and eigen-value decomposition power allocation (EVD-PA). While the approximations are tight in the large system limit with an infinitely large number of antennas and user terminals, they also match our simulations for realistic system dimensions. We further show that a simple EVD-PA detection scheme can achieve the same performance as MMSE with one order of magnitude fewer antennas in both uncorrelated and correlated fading channels. Our simulation results show that our proposal is a better detection scheme than the conventional scheme for LSAS. Also, we used two channel environment channels for further analysis of our algorithm: the Long Term Evolution Advanced channel and the Millimeter wave Mobile Broadband channel.
The analysis and design of relay protocols is a hot issue in 3GPP Long Term Evolution—Advanced. In this paper, we discuss interference cancellation in a multiuser MIMO environment using Amplify-and-Forward (AF), Decode-and-Forward (DF) and De-Modulate-and-Forward (DMF) as relay protocols, and using Thomilson Harashima Precoding and Dirty Paper Coding as precoding techniques, with Zero-Forcing, Minimum Mean Square Error, Successive Interference Cancellation and Ordered Successive Interference Cancellation detection techniques. By using a combination of classical precoding schemes and detection techniques with weighted matrix, we propose a new interference cancellation technique that is capable of cancelling interference. The interference cancellation is managed by AF, DF and DMF relay node protocols and the interference free codeword is transmitted to the selected User Equipment. The proposed algorithm when used with DMF protocol shows best performance, compared to the conventional system or the no-relay system case, it gives best performance. The observation results shows that DMF protocol gives the best results for BER and Throughput performance in a high interference environment. 相似文献
Advances in the field of medical sciences and medical technology, and
present-day challenges, such as an aging population, rising medical expenses, and
lifestyle-related diseases, have collectively catalyzed a research ecosystem termed
“smart wellness.” This article describes the establishment of a smart wellness service platform designed to empower individuals to create a sense of balance in
their lives. Step-by-step details include service model, design, and architectural
considerations. As a proof of concept, implementation details of a Health
Improvement and Management Systems (HIMS) Hub, a Smart Wellness Service
Platform deployed in six cities in South Korea, are presented. An on-site survey
conducted in Busan Metropolitan City reveals the percentage of satisfied users to
be 91.3%. Furthermore, data gathered from 27,236 physical evaluations of users
from a Busan city center over the period of April 2013 to May 2018 reveal that
males and females in their 50s and 60s account for the highest number of participants, while males in their 70s have a higher rate of participation than females
in the same age group. 相似文献
Wireless Personal Communications - Wireless solar blind ultraviolet (UV) scattering communication is a new type of atmosphere optics communication technology with the important and potential... 相似文献
Wireless Personal Communications - Generally, a ground telemetry station for a launch vehicle (LV) includes a tracking function only; therefore, position measurements for LV depend on received... 相似文献
Peer-to-Peer Networking and Applications - Recently, due to the popularity of smart devices, a need for various types of wireless communication has been tremendously increasing and several types of... 相似文献
This paper introduces a fundamental energy efficient hybrid P2P transmission technology for P2P networking environment as well as Internet of Everything (IoE) infrastructure. Based on the transmission characteristics of wireless communication technologies of Bluetooth and Wi-Fi, the proposed P2P transmission technique integrates them into an energy efficient hybrid transmission technology and provides the IPification for specific group, society, and the entire world. We have shown that the proposed hybrid transmission technology outperforms the existing transmission technologies in the aspects of initial connection establishment time and overall data transmission capability. 相似文献
IMT-Advanced mobile communication systems make it possible for any devices to access high-speed networks anytime and anywhere.
To meet the needs of IMT-Advanced systems, cellular systems must solve the problem of intercell interference caused by frequency
reuse. Intercell interference problems become severe when orthogonal frequency division multiplexing (OFDM) transmission,
which is a key technology for 4G communication systems, is used in a cellular system. In this paper, a zone-based intercell
interference coordination (ICIC) scheme with high flexibility and low cost is proposed, and its performance is evaluated through
multicell system-level simulations carried out according to the simplified 3GPP (3rd Generation Partnership Project) Long
Term Evolution (LTE) system parameters. In the proposed algorithm, each cell is divided into several regions based on threshold
values. Each region reuses frequencies in different ways, and the regions have different maximum transmit (TX) powers according
to the interference environment. Even though the proposed scheme can be implemented with low complexity by using only the
existing user equipment (UE) measurement, simulation results have confirmed that it provides significant improvements in geometry
distribution. 相似文献
The authors propose a new method for the modeling and call admission control (CAC) of variable bit rate video source, which come to the front of ATM networks as hot issues nowadays. First, the modeling of video source is accomplished using the three-state Markov chains including the effects of scene change at which the bit rate of video source is abruptly increased. Also, using two AR models, they improve the defects which an AR model has in modeling a video source. In addition, they represent the analytical model of a video source so that a network manager can acquire the information which is very important in managing the entire networks. CAC is accomplished using the previously defined analytical model. A routing manager calculates the cell loss probability of a chosen VP where a new call is connected so that the routing manager decides whether this new call is accepted or not. This calculation is accomplished through the GB/D/1-S queuing system. Using BIA (bandwidth increasing algorithm), they check whether the calls rejected by the routing manager could be accepted if possible. Finally, the applicable procedures to suitable allocate bandwidth to each VP on a link are presented in detail 相似文献