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Space Time Block Coded MIMO Systems
Published in Brijesh Kumbhani, Rakhesh Singh Kshetrimayum, MIMO Wireless Communications over Generalized Fading Channels, 2017
Brijesh Kumbhani, Rakhesh Singh Kshetrimayum
Space time block coded (STBC) systems began with a purpose of providing transmit diversity for multiple-input multiple-output (MIMO) systems. The foundations of STBC codes were laid down by Alamouti and hence the scheme with two transmit antennas is known as Alamouti STBC scheme [2]. We had brief discussions on basics of transmission and detection of STBC symbols using multiple antennas in Chapter 1. There we considered only the Alamouti transmission scheme which is a special case of STBC codes. Unlike in spatial modulation (SM) and transmit antenna selection (TAS), symbols are transmitted simultaneously in STBC from all antennas at the transmitter. This increases the hardware complexity as simultaneous transmission needs an radio frequency (RF) chain for each transmitting antenna. However, STBC schemes are capable of achieving full diversity orders unlike the SM systems. Though TAS systems can achieve full diversity order, they need feedback from the receiver to the transmitter in order to make the decision of the antenna to be selected for transmission. Thus, each STBC, TAS and SM system has its own merits and may be a good candidate for commercial use. But a system may be chosen as per the requirements for implementation.
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
During the last decade, MIMO technology has received a lot of attention because of the potential improvement in throughput and reduction in energy consumption that this technology provides. Generally speaking, MIMO technology increases spectral efficiency by exploiting the spatial diversity that is attained through the physical separation of multiple antennas in space. The advantages of MIMO systems can be divided into three main categories [80]: Spatial multiplexing for enhancing the data transmission rateTransmit diversity using space–time coding for enhancing the transmission robustness, andBeamforming for improving the received signal and reducing interference to other users
MIMO Systems for Diversity and Interference Mitigation
Published in Jerry D. Gibson, Mobile Communications Handbook, 2017
In the presence of fading, the received power level can present large variations. Diversity is used to reduce the variations of the SNR level due to fading, by sending each information symbol through different channels with independent fading levels, and then combining the outputs. In a NT × NR MIMO channel, there are potentially NT · NR links. Spatial diversity can be obtained with multiple receiving antennas with CSIR (receive diversity), and with multiple transmit antennas (transmit diversity). Transmit diversity is possible both with CSIT (beamforming) and even in the absence of CSIT (Alamouti's code, space–time codes).
Performance statistics of broadcasting networks with receiver diversity and Fountain codes
Published in Journal of Information and Telecommunication, 2023
Lam-Thanh Tu, Tan N. Nguyen, Phuong T. Tran, Tran Trung Duy, Quang-Sang Nguyen
Before highlighting main contributions and novelties of the paper. Let us review the state-of-the-art of Fountain codes and receiver diversity schemes. Particularly, the performance of Fountain codes was studied extensively in Dang et al. (2019), Danufane and Di Renzo (2021), Li et al. (2020), Lim et al. (2021), Tran et al. (2012), and Tran et al. (2021) while the performance of receiver diversity was given in Arya and Chung (2018), Liao et al. (2018), Phu et al. (2020), and Tsai et al. (2022). Particularly, Dang et al. (2019) derived the outage probability (OP) of the multiple-input multiple-output (MIMO) systems with and without employing non-orthogonal multiple access (NOMA). The results showed that with NOMA, ones can save a significant number of time slots to convey the message compared with non-NOMA systems. They, however, consider only the single-user scenario rather than multi-user cases. Numerical results unveiled that the power splitting protocol is better than the time switching protocol. They, nonetheless, do not take into account the receiver diversity scheme. The comparison between FC and random linear network coding (RLNC) in short packet communications (SPC) was conducted in Li et al. (2020). Their outcomes stated that the SPC FC scheme provides better performance. Particularly, it has a smaller decoding error probability compared with RLNC. Besides, the authors in Lim et al. (2021) proposed a novel Fountain code dedicated to the SPC. The results revealed that their proposed Fountain code attains a lower bit error rate and higher rate compared to the conventional FC scheme. The distribution of the average time slot to deliver a packet in cellular networks was studied in Danufane and Di Renzo (2021) via tools from stochastic geometry (SG) (Al Hajj et al., 2020). Duy and others derived the average time slots in multi-hop communications with FCs in the closed-form equation (Tran et al., 2012) and the performance of the cooperative cognitive radio networks (CCRNs) employing FCs was investigated in Tran et al. (2021). Authors in Tsai et al. (2022) focussed on the diversity techniques at the receiver. The application of the receiver diversity technique in ultraviolet (UV) communications was studied in Arya and Chung (2018). More precisely, the switch and stay combining (SSC) was applied to improve the outage probability and symbol error probability (SEP). The maximal ratio combining scheme was used in Liao et al. (2018) to improve the coverage area as well as the diversity gain. The performance of transmit antenna selection (TAS) combined with Fountain code was studied in Phu et al. (2020). They, however, consider point-to-point communications and transmit diversity which requires the perfect channel state information at the transmitter (CSIT) that is difficult to obtain in practice.