107 research outputs found
Performance analysis of diversity techniques in wireless communication systems: Cooperative systems with CCI and MIMO-OFDM systems
This Dissertation analyzes the performance of ecient digital commu- nication systems, the performance analysis includes the bit error rate (BER) of dier- ent binary and M-ary modulation schemes, and the average channel capacity (ACC) under dierent adaptive transmission protocols, namely, the simultaneous power and rate adaptation protocol (OPRA), the optimal rate with xed power protocol (ORA), the channel inversion with xed rate protocol (CIFR), and the truncated channel in- version with xed transmit power protocol (CTIFR). In this dissertation, BER and ACC performance of interference-limited dual-hop decode-and-forward (DF) relay- ing cooperative systems with co-channel interference (CCI) at both the relay and destination nodes is analyzed in small-scale multipath Nakagami-m fading channels with arbitrary (integer as well as non-integer) values of m. This channel condition is assumed for both the desired signal as well as co-channel interfering signals. In addition, the practical case of unequal average fading powers between the two hops is assumed in the analysis. The analysis assumes an arbitrary number of indepen- dent and non-identically distributed (i.n.i.d.) interfering signals at both relay (R) and destination (D) nodes. Also, the work extended to the case when the receiver employs the maximum ratio combining (MRC) and the equal gain combining (EGC) schemes to exploit the diversity gain
A virtual MIMO dual-hop architecture based on hybrid spatial modulation
International audienceIn this paper, we propose a novel Virtual Multiple-Input-Multiple-Output (VMIMO) architecture based on the concept of Spatial Modulation (SM). Using a dual-hop and Decode-and-Forward protocol, we form a distributed system, called Dual-Hop Hybrid SM (DH-HSM). DH-HSM conveys information from a Source Node (SN) to a Destination Node (DN) via multiple Relay Nodes (RNs). The spatial position of the RNs is exploited for transferring information in addition to, or even without, a conventional symbol. In order to increase the performance of our architecture, while keeping the complexity of the RNs and DN low, we employ linear precoding using Channel State Information (CSI) at the SN. In this way, we form a Receive-Spatial Modulation (R-SM) pattern from the SN to the RNs, which is able to employ a centralized coordinated or a distributed uncoordinated detection algorithm at the RNs. In addition, we focus on the SN and propose two regularized linear precoding methods that employ realistic Imperfect Channel State Information at the Transmitter. The power of each precoder is analyzed theoretically. Using the Bit Error Rate (BER) metric, we evaluate our architecture against the following benchmark systems: 1) single relay; 2) best relay selection; 3) distributed Space Time Block Coding (STBC) VMIMO scheme; and 4) the direct communication link. We show that DH-HSM is able to achieve significant Signal-to-Noise Ratio (SNR) gains, which can be as high as 10.5 dB for a very large scale system setup. In order to verify our simulation results, we provide an analytical framework for the evaluation of the Average Bit Error Probability (ABEP)
Full duplex-transceivers : architectures and performance analysis
PhD ThesisThe revolution of the 5G communication systems will result in 10,000 times increase
in the total mobile broadband traffic in the 2020s, which will increase the
demand on the limited wireless spectrum. This has highlighted the need for an
efficient frequency-reuse technique that can meet the ever-increasing demand on
the available frequency resources. In-band full-duplex (FD) wireless technology
that enables the transceiver nodes to transmit and receive simultaneously over the
same frequency band, has gained tremendous attention as a promising technology
to double the spectral efficiency of the traditional half-duplex (HD) systems. However,
this technology faces a formidable challenge, that is the large power difference
between the self-interference (SI) signal and the signal of interest from a remote
transceiver node. In this thesis, we focus on the architecture of the FD transceivers
and investigate their ability to approximately double the throughput and the spectral
efficiency of the conventional HD systems. Moreover, this thesis is concerned with
the design of efficient self-interference cancellation schemes that can be combined
with the architecture of the FD transceiver nodes in order to effectively suppress the
SI signal and enable the FD mode. In particular, an orthogonal frequency-division
multiplexing (OFDM) based amplify-and-forward (AF) FD physical-layer network
coding (PLNC) system is proposed. To enable the FD mode in the proposed system,
a hybrid SIC scheme that is a combination of passive SIC mechanism and
active SIC technique is exploited at each transceiver node of that system. Next, we
propose an adaptive SIC scheme, which utilizes the normalized least-mean-square
(NLMS) algorithm to effectively suppress the SI signal to the level of the noise
floor. The proposed adaptive SIC is then utilized in a denoise-and-forward (DNF)
FD-PLNC system to enable the FD mode. Finally, we introduce a novel overthe-
air SIC scheme that can effectively mitigate the SI signal before it arrives the
local analog-to-digital converter (ADC) of the FD transceiver nodes. Furthermore,
the impact of the hardware impairments on the performance of the introduced SIC
scheme is examined and characterized.Iraq, and the Ministry of
Higher Education and Scientific Research (MOHSR
Performance Analysis of Dual-Hop MIMO AF Relaying Network with Multiple Interferences
In this paper, we investigate the performance of a dual-hop multiple-input-multiple-output (MIMO) amplify-and-forward (AF) relay network, where the source, relay, and destination are all equipped with multiple antennas. By using maximum ratio transmission (MRT) at the transmitter and maximum ratio combining (MRC) at the receiver, we first obtain the output signal-to-interference-plus-noise ratio (SINR) of the dual-hop AF relay system, considering multiple cochannel interferences (CCIs), as well as noise at the relay. Then, we derive an exact closed-form expression for the outage probability (OP), and the asymptotic result of OP at high SNR, which can be used to calculate the array gain and diversity order. Finally, computer simulations are conducted to validate the performance analysis. Our new analytical expressions not only provide a fast and efficient method to evaluate the system performance but enable us to gain valuable insights into the effects of key parameters on the MIMO AF relaying network performance that benefits from implementing multiple antennas at each of the three nodes as well
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