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Recently massive multi-input multi-output (MIMO) techniques have attracted growing research interest. However, most existing works assume centralized control, which may involve a heavy overhead as the number of users also becomes massive. In this paper, we focus on random-access massive MIMO systems. We first analyze the performances of two conventional schemes widely used in massive MIMO, and derive...
Full duplex transmission is envisioned as one of the potential breakthrough for a Generation (5G) radio access technology. In this paper, we evaluate the performance of full duplex transmission in a network of dense small cells by using real channel measurements. A large measurement campaign is carried out in an indoor office and an open hall scenario, and such measurements are then fed to...
Given the recent advances in system and antenna design, practical implementation of full duplex (FD) communication is becoming increasingly feasible. In this paper, the potential of FD in enhancing the performance of 5th generation (5G) ultra-dense small cell networks is investigated. The goal is to understand whether FD is able to boost the system performance from a throughput and delay perspective...
The continuous rise in wireless data traffic brings forth an increase in power consumption and static users constitute a large fraction of these traffic demands. This work focuses on designing cellular networks to deliver a given data rate per area and user, while minimizing the power consumption. In particular we are interested in optimizing the transmission power, density of access points (APs),...
We evaluate the performance of a dual-polarized wideband antenna in terms of polarization-MIMO in Random-LOS for two different modes of operation: 2 and 4-port excited mode. The 2-port mode was obtained by differential excitation of two opposite ports of the 4-port design by using two baluns. The Zero-Forcing receiver throughput is evaluated based on the Probability of Detection of two bitstreams...
Ambient noise not only influences the data transmission but also causes incorrect CSI. To overcome the low SNR problem, traditional methods usually retransmit the same packet for enough times to increase the SNR. Unfortunately, recently works only focus on the failed data retransmission, yet totally overlook the incorrect channel estimation, which are not efficient for multi-user MIMO WLAN. As long...
This paper introduce one novel in-lab test method to reproduce a field radio channel data in lab, and use one recorded field data as an example to evaluate TDD-LTE UE performance. Firstly, it presents the field measurement method based on the scanner, and then to introduce accurate modeling way as conversion to generate in-lab playbacking file and also mapping to support CE based MPAC test solution,...
This paper discusses recent developments with the two-stage MIMO OTA test method. It first introduces the concept of the radiated two-stage (RTS) method which is based on a first stage of antenna pattern measurement followed by a second stage of throughput measurement using a signal generated by convolving the device antenna pattern with the desired spatial channel model. The resulting signal is applied...
Different standardization bodies are working towards test methodologies and procedures to determine true Multiple Impute Multiple Output (MIMO) performance. A reference CTIA (Cellular Telecommunications and Internet Association) 2×2 Long Term Evolution (LTE) MIMO antenna concept has been designed [1–2] and verified [3] to eliminate the uncertainties linked to the unknown antenna performance of the...
The handset MIMO antenna is studied by using an in-house developed MIMO system, which can accommodate up to 8 antennas at both Tx and Rx sides. At first, a group of handsets with different number of antennas are designed and fabricated. The mutual coupling and efficiency of the antennas are measured. Then the handsets are inserted into the MIMO system, the channel matrix and throughput achieved by...
The recently approved IEEE 802.11ac WLAN standard has dramatically boosted Wi-Fi capabilities through supporting more data streams, larger bandwidth and more efficient frame-aggregation, leading to significantly higher data rates. The multitude of data rates and MIMO configurations to choose from has made it crucial to develop efficient algorithms for rate adaptation and MIMO mode selection (spatial...
This paper considers a hybrid heterogeneous network (HetNet), where macro cells adopt massive multiple-input multiple-output (MIMO), and small cells adopt millimeter wave (mmWave) transmissions. We assume that all base stations (BSs) are solely powered by the renewable energy. The implementation of these emerging techniques has a substantial effect on the user association (UA). Motivated by this,...
In this paper, we investigate three-dimensional (3D) multi-user (MU) multiple-input multiple-output (MIMO) transmission for long term evolution advanced (LTE-A) downlink systems. We investigate some key techniques for 3D MU-MIMO to improve the performance of LTE-A systems, including rank and precoding matrix (PM) determination and user pairing. To reduce the complexity caused by a large number of...
Autonomous cars will in a near future drive around in cities and on highways. Antennas will then be needed to secure the wireless connection to these cars. To be able to test the antennas we have defined two edge environments: the Random Line-of-Sight (LOS) and the Rich Isotropic Multipath (RIMP). This paper shows a throughput performance comparison between measurements and simulations of a car-roof...
Due to the scarcity of the available spectrum bands, Cognitive Radio (CR) has been proposed as a promising paradigm. One of the most important research area is how to maximize Secondary User (SU) system throughput while assuring the Quality of service of Primary User (PU) system. Multiple-Input-Multiple-Output (MIMO) is an efficient technique, exploiting space diversity, used for increasing SUs throughput...
Joint processing coordinated multipoint (JP-CoMP) is a new technology in LTE-A adopted to enhance the throughput of cell edge users as well as to mitigate interference. Relay Nodes (RNs) have also proven useful toward the realization of LTE-A, in improving the signal quality for the cell edge users. In this paper, we propose to combine JP-CoMP and relaying techniques for further improvements at the...
In this paper we investigate the performance of multiple input multiple output (MIMO) systems with transmit antenna selection when N-process Stop and Wait (N-SAW) is applied at the data link layer. Two antenna selection schemes, throughput and capacity based transmit antenna selection, are considered. In throughput based transmit antenna selection, cross layer information is used to select antennas...
Massive MIMO is the new emerging technology which can be used to increase the data rate. Massive MIMO reap all benefits of conventional MIMO. In Massive MIMO we use the receiver diversity. In this paper we are proposing Opportunistic space division multiple access technology with beam selection for massive MIMO system technology. OSDMA-S is the technology in which we generate a orthonormal beam which...
The ever increasing number of mobile broadband users requires the availability of enhanced data services. Long Term Evolution or LTE is the evolution of High Speed Packet Access (HSPA), which was standardized by third generation partnership project (3GPP) Release 8 in order to meet the increasing demand of faster and more efficient mobile internet access today by supporting the larger bandwidth. This...
Limited feedback scheduling algorithms for multiuser MIMO-OFDM is discussed for heterogeneous network in the sense that SNR for all users are not equal. Users at a particular distance from base station are grouped together and have same SNR assuming that they have same multipath profile and shadowing effect. In this paper, closed-loop system is considered where mobile terminals feedback channel quality...
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