301 Moved Permanently. The requested resource has been assigned a new permanent URI. Powered by Tengine. 4×4 MIMO means that with exactly the same resource blocks on the air interface, the base station transmits 4 different signals (or streams) via 4 transmit antennas to one user equipment (UE). To receive the signals and benefit most, however, the UE must be equipped with 4 antennas as well. Oct 28, 2015 Since mimoLive Beta 7 we introduced a new way of adding and working with layers. In this video we'll show you how to use the layers. Turn your Mac into a live video production studio with mimolive. Rev.from DVLのホーカゴ（2015年4月7日 - 、U-NEXT） （2015年8月20日 - 、Kawaiian TV） - MC 田中圭24時間テレビ（2018年12月15日 - 12月16日、 AbemaSPECIAL2 ） - 配信中に撮影したドラマ『くちびるWANTED』劇中使用のインサートカットの撮影。. Jun 10, 2016 Use MimoLive to create a professional looking elementary news broadcast. PTZOptics 15,231 views. JAVA - How To Design Login And Register Form In Java Netbeans - Duration: 44:14.
The various macro network enhancements available today offer a cost-efficient and smart approach for capacity increase in mobile networks. In the first part of this series, we provided an overview of the hardware-related capacity enhancing features and discussed carrier aggregation in detail. The second part of this series discusses higher order MIMO antenna configurations, particularly 4×4 MIMO.
The potential of this specific operating mode lies in enabling radio systems to achieve significant performance gains by using multiple (4) antennas at their transmitters and receivers.
4×4 MIMO has already been specified in the 3GPP Release 8, the first LTE standardization release, frozen in 2008. 3GPP’s (3rd Generation Partnership Project) latest Release 13 is currently frozen. It is only now that operators are planning 4×4 MIMO deployments.
MIMO stands for Multiple Input Multiple Output and can also be described as spatial multiplexing. It enables the transmission of more than 1 signal to 1 user via the same set of air interface resources. The feature builds on uncorrelated paths In other words, it builds on uncorrelated transmit and receive antennas and uncorrelated paths (multipaths) on the air interface (the channel).
4×4 MIMO means that with exactly the same resource blocks on the air interface, the base station transmits 4 different signals (or streams) via 4 transmit antennas to one user equipment (UE). To receive the signals and benefit most, however, the UE must be equipped with 4 antennas as well. In theory, this doubles the downlink throughput per resource block compared with 2×2 MIMO, today’s state-of-the art MIMO operating mode.
To discuss 4×4 MIMO comprehensively, this post focuses on the
Today in LTE networks, 2×2 MIMO is state–of-the-art. Base stations are typically using cross-polarized antennas (normally slanted at +45/- 45 degree for the 2 polarization directions). The 2 polarization directions are orthogonal to each other. This means they are uncorrelated.
By using 2 cross-polarized antennas, 4 uncorrelated paths with 4 antennas can be realized. To get full decorrelation between these 2 antenna columns, however, we would need a distance of at least 10 wavelengths between them. The distance, equal to 10 times lambda (3.80 m in 800 MHz or 1.70 m in 1800 MHz), between the 2 antenna columns would have a severe impact on the base station site installation. And even though it is certainly possible to mount the 2 antenna columns closer to one another, the imperfect decorrelation would significantly compromise MIMO gain.
To receive 4 streams (different signals), the UE requires 4 receive paths and 4 uncorrelated antennas. A new type of user equipment is necessary. Currently commercially available devices (e.g. smartphones) include only 2 receive paths and 2 antennas. This is perfect for 2×2 MIMO, but not applicable for 4×4 MIMO. In the past years, the availability of 4 Rx (receiver) capable devices has been and still is impeding the commercial deployment of 4×4 MIMO. What we can say today is that the issue with 4 uncorrelated receive antennas in a form factor of a smartphone is unsolved yet.
Although 4×4 MIMO capable devices are not yet available, 4 Tx (transmitter) antennas on the base station side have been frequently deployed in the past months. The 4 Tx RF chains in base stations can be used for the following features that only require 2×2 MIMO capable devices:
To be able to truly transmit and receive 4 streams, the channel or air interface has to offer enough uncorrelated paths (i.e. sufficient multipath richness). Cisdem pdf to word converter 7 0 0 2. A channel’s multipath availability is independent of the used technology and mainly depends on the topology or the environment of the network: MIMO is most effective when there is significant multipath propagation. This is usually the case in urban and dense urban environments where signals are scattered by buildings and other objects. Where there is a strong line-of-sight transmission path between the transmitter and receiver, such as in open and rural locations, MIMO is less useful.
The channel for a 4×4 MIMO transmission can be characterized by a 4×4 channel matrix. The receiver knows the receive signal. To get the transmit signal back, it needs to estimate the 16 channel matrix components. In mathematical terms, the receiver needs to solve the linear equations. This is a dynamic process, as the channel can vary quite quickly.
Bookends 12 2 3 – reference management and bibliography software. The channel matrix can be characterized by 2 important parameters: the rank and the condition number.
The biggest challenge for operators regarding 4×4 MIMO is to calculate the business case (costs vs. benefits).
As 4×4 MIMO feasibility is mainly dependent on the structural environment, operators are encouraged to investigate its practicability by upgrading a few trial sites to 4 transmit paths (together with their infrastructure suppliers).
The following Rohde & Schwarz mobile network testing solution (consisting of 4 TSME scanners, a 4-receive antenna (prototype), and the ROMES analysis SW) can measure or better estimate the channel matrix components and calculate the rank and condition number of the channel matrix which is a really unique feature. With this feature set of the 4×4 MIMO measurement solution, mobile network operators can test different positions and identify typical environments in which 4×4 MIMO deployment is beneficial, offering a return on investment.
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