Downlink MIMO
For the downlink MIMO system configurations with two or four antennas has being considered. In 2x2 configurations there is baseline configuration with two antennas at the transmitter and two antennas at the receiver. There are different modes has been predicted for MIMO antenna system such as spatial multiplexing and transmit diversity and channel automatically select any scheme of choice.
Spatial multiplexing
In spatial multiplexing scheme the different stream of data has been transmitted on the same downlink resource block. As there is SU-MIMO (Single user MIMO) and MU-MIMO (Multiuser MIMO) and the data stream could be related to one of these. SU-MIMO is used to achieve higher data rate whereas on the other hand MU-MIMO is
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Precoding matrix principle
The precoding matrix has been chosen from the predefined codebook which is called eNodeB and UE side. Mostly the unity pre-coding is used in which the precoding matrixes are unitary. The UE chose the best pre-coding matrix by predicting the radio channel. This pre-coding matrix the further provides the maximum capacity. On the uplink control channel the UE also provides the feedback which shows the preferred pre-coding matrix. The optimum pre-coding matrix varies between each resource block. Uplink MIMO Uplink
For uplink MIMO scheme is different from downlink MIMO. MU-MIMO is used for the uplink MIMO. This is also called spatial domain multiple access (SDMA) in which multiple users can transmit at the same time on the same resource block. The major benefit of this scheme is that it only requires only one transmit antenna at UE side. The UE must have to follow the mutually orthogonal pilot patterns as they using the same resource block. In the starting technique the UE have two transmit antenna with only one transmit chain and amplifier and switch is used to choose the antenna that is able to provide the best channel to the eNodeB
VII. Performance improvement in MIMO system
The performance improvement in MIMO systems could be achieved from array gain, diversity gain, spatial multiplexing gain and the reduction in the interference. The advantages of these
In the Multihop Virtual Multiple Input Multiple Output (MIMO) the data are collected by multiple source nodes and transmitted to a remote sink by multiple hops [11]. In this, the cluster head sends message to sensor nodes in the cluster. Next the sensor nodes encode the data and sends to cluster head in the next hope according to the orthogonal Space Time Block Code [STBC]. It saves the energy and provides QoS provisioning.
signals between the source and the antenna. Any array architecture requires partitioning the transceiver functions into those implemented close to the respective antennas and those implemented at the main system controller. Transceiver can be subdivided into three parts
Abstract: In this paper, we propose a design for multiple antenna full-duplex (FD) eNodeB (eNB) and user equipment (UE) transceiver, based on recent progress in the area of self-interference cancellation (SIC). For FD communication, .i.e., simultaneous in-band uplink and downlink operation, same subcarriers are allocated to UE in both uplink and downlink. Hence, contrary to traditional LTE, we propose using single-carrier frequency division multiple accesses (SC-FDMA) for downlink along with the conventional method of using it for uplink. Taking advantage of channel reciprocity in the case of FD communication and multiple antennas at eNB, use of singular value decomposition (SVD) in the downlink allows multiple user (MU) to operate
In developing 5G, a lot of efforts have been made in three different areas: spectrum expansion, spectrum efficiency and network densification. In network densification, there made a large number of small cells. These small cells have small area of coverage. Due to the deployment of small cells, there is an increase in complexity. Due to this , a network operator has to face many problems:
802.11ac only works in the 5GHz band, which means that any equipment want to work in 802.11ac must support 5GHz frequency band. Furthermore, 802.11ac’s chipset also supports 2.4GHz band, to supports 802.11a/b/g/n WLAN and other previous standard, to provide backward compatibility.
MIMO techniques are mostly used to accelerate system throughput over disruptive wireless communication channels. It is well known fact that with the number of transmit antenna M and number of receive antenna N, the capacity of MIMO systems increases linearly with a factor of MN. The receiver decodes the received signal vectors into actual information, a narrow band flat fading MIMO is designed as:
By performing this examination, we have learnt that coding enhances the general execution of the MIMO. It can be seen that without coding,
Keywords- Multiple-input multiple-output (MIMO), orthogonal space time block code (OSTBC), maximal ratio combining (MRC), Weibull-gamma (WG) fading, symbol error rate (SER).
In this type of MIMO system the processing of signals occurs at the receiver only. Receiver processing system is mostly beneficial in the uplink scenario as the signal processing is restricted to the receiver and as at the mobile station no MIMO signal would be required. In case of uplink scenario, there is a single data stream which is demultiplexed into the N number of substream, and each substream is further modulated and passed it into N number of transmitters.
In recent years, wireless multiple-input multiple-output (MIMO) system using antenna arrays are fetching attention owing to their significantly higher system capacity [1],[2]. Cooperative communication is now a concerning topic of
In our approach of cross layer design along with link SNR, fading effect and FEC role is also accounted to find a stable routes.
4G wireless mobile communication networks are been specified to support display, battery and computational power etc. 4G wireless mobile communication networks should not focus on air interface and data rate, but instead cover advance wireless mobile communication networks and high speed wireless access system into different platforms. Based on different model, 4G wireless
● In this case whenever a station becomes ready to send it senses the channel
In fact the technology transfers thousands of streams of data simultaneously, in parallel, in higher speeds with the help of special modulation, using a unique signal processing technology.
Wireless communications is, by any measure, the fastest growing segment of the communications industry. It has captured the attention of the media and the imagination of the public. However, the fundamental phenomenon which makes transmission unreliable is time varying fading. The phenomenon is described as the constructive/destructive interference between signals arriving at the same antenna via different paths, and hence with different delays and phases, resulting in random fluctuations of the signal level at the receiver. This paper investigates Rake receiver method of combating fading.