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Four-element wave patch multiband MIMO antenna for 5G application
Published in Yadwinder Kumar, Shrivishal Tripathi, Balwinder Raj, Multifunctional MIMO Antennas, 2022
Richa Kumari, Yadwinder Kumar, Ajay Mudgil, Balwinder Singh
The two methods employed for MIMO wireless communication are space-time block coding and spatial multiplexing. In space-time block coding, a copy of the same data that has been transmitted at time t1 is transmitted again at time t2. However, this is not an exact copy but a manipulated one, so that the exact information can be extracted out of the multipath propagation. It does not enhance the bit rate but is useful in reducing the bit error rate. In spatial multiplexing, data is split and transmitted via different antenna elements to the receiver, where, after signal processing, the exact data is retrieved. Its disadvantages include the complex signal processing required after signal reception. Both the techniques are used together in wireless systems to gain benefits in terms of both coverage and data rate, according to modified Shannon equation, shown in Equation 7.1 [1]. This technique has been widely adopted in the latest wireless standards such as wireless local area network (WLAN), Worldwide Interoperability for Microwave Access (WiMAX), and Long-Term Evolution (LTE). C=MBlog1+NM×SNR
Antenna Selection in MIMO Systems
Published in George Tsoulos, MIMO System Technology for Wireless Communications, 2018
Neelesh B. Mehta, Andreas F. Molisch
MIMO systems, which employ multiple transmit and receive antenna elements, substantially improve the data rates that can be transmitted over the channel and the reliability with which they can be received without any additional bandwidth. Higher data rates are achieved by transmitting multiple data streams simultaneously using spatial multiplexing techniques. For spatially uncorrelated channels, the data rates even increase linearly with the minimum of the number of transmit and receive antenna elements [1]. Increased reliability is achieved by exploiting spatial diversity to significantly reduce the probability that the channel is in a deep fade. Orthogonal space–time block codes and space–time trellis codes are examples of diversity techniques tailored to MIMO systems. A single input multiple output (SIMO) system, which combines the many received copies of the transmitted signal to improve reliability, is another example of a spatial diversity system.
Next Generation Wireless Technologies
Published in K. R. Rao, Zoran S. Bojkovic, Bojan M. Bakmaz, Wireless Multimedia Communication Systems, 2017
K. R. Rao, Zoran S. Bojkovic, Bojan M. Bakmaz
Spatial multiplexing [81] is a MIMO technique in which independent and separately encoded data signals, called streams, are transmitted from multiple antennas. This technique requires multiple antennas at both ends of the radio link (Nt ≥ 2 and Nr ≥ 2), and also there is no need for channel information at the transmitter. Under the spatial multiplexing mode, the achievable capacity (maximum spatial multiplexing order) is Ns = min(Nt, Nr). For linear receivers, this means that Ns streams can be transmitted in parallel, leading to an Ns increase in the spectral efficiency. If the transmitted streams arrive at the receiver with sufficiently different spatial signatures, the receiver can separate them. As a result, an increment in the channel capacity is achieved.
Joint CFO and channel estimation using pilot aided interpolation for high performance MIMO-OFDM
Published in International Journal of Electronics, 2023
S. Chitra, S. Ramesh, Ramya Vijay, G. Jegan, T. Samraj Lawrence
The spectrum and data rate for 4 G and 5 G wireless standards are in high demand to enable for a wide range of applications. Since the wireless channel is impeded by fading and additive noise, transmission of huge amounts of data over such channel is a challenging. Multiple Input Multiple Output (MIMO) is a technology that employs multiple antennas at the transmitter and receiver to exploit multiple independent channels. It utilises the benefits of spatial multiplexing and spatial diversity to achieve high data rates and bandwidth efficiency by simultaneously transmitting data over multiple antennas. The basic principle of MIMO is space-time (SenthilKumar et al., 2020) or space-frequency signal processing which is exploited through the number of spatially distributed antennas at both transmitter and receiver. In comparison to single antenna systems, MIMO offers higher capacity and better service quality.
BER analysis of ZF receiver with imperfect CSI for fully correlated channel
Published in International Journal of Electronics Letters, 2021
Supraja Eduru, Nakkeeran Rangaswamy
Multiple Input Multiple Output (MIMO) systems can afford high speed reliable wireless communication over fading channels (Agiwal et al., 2016). To combat the growing demands of the data rate, the MIMO systems with a huge number of antennas at the transmitter and the receiver are considered (Chockalingam & Sundar Rajan, 2014; Gao et al., 2015). However, due to frequency constraints and antenna size, less spacing among the antennas introduces correlation between the subchannels, which in turn creates a substantial impact on channel capacity and BER (Masouros et al., 2013). Besides this, a similar problem occurred due to the error in channel estimation that was well explained in Yoo and Goldsmith (2006) and Benkhelifa et al. (2014). Further, to exploit the MIMO system capacity, spatial multiplexing is used, where the information streams are transmitted independently. The respective information streams are recovered at the receiver by employing detection schemes like Maximum Likelihood (ML), sphere decoding, Minimum Mean Square Error (MMSE) and Zero-Forcing (ZF) (Damen et al., 2003; Foschini et al., 1999; Murugan et al., 2006). Among them, ZF is simple and widely used for massive MIMO systems (Seethaler et al., 2005).
Towards Connected Living: 5G Enabled Internet of Things (IoT)
Published in IETE Technical Review, 2018
Mamta Agiwal, Navrati Saxena, Abhishek Roy
High-frequency mmWave band in Figure 4(a), ranging from 3 to 300 GHz, offers answers to spectrum limitations in wireless communications [6]. The paradigm shift to this unused mmWave spectrum is motivated by the availability of 10–100 times cheaper per Hz big chunks of bandwidth [9]. Moreover, Complementary Metal-Oxide-Semiconductor (CMOS) technology support and high-gain directive antennas further accentuate the popularity of mmWave communication [3]. This immense capacity offers support for a very large number of devices in an IoT landscape. Furthermore, mmWave-driven directional air interface enables spatial capabilities. Together with high bandwidth, spatial multiplexing would further enhance network capacity and is expected to alleviate signalling, congestion, and network overloads.