39 research outputs found
Performance Analysis of a Dual-Hop Cooperative Relay Network with Co-Channel Interference
This paper analyzes the performance of a dual-hop amplify-and-forward (AF) cooperative relay network in the presence of direct link between the source and destination and multiple co-channel interferences (CCIs) at the relay. Specifically, we derive the new analytical expressions for the moment generating function (MGF) of the output signal-to-interference-plus-noise ratio (SINR) and the average symbol error rate (ASER) of the relay network. Computer simulations are given to confirm the validity of the analytical results and show the effects of direct link and interference on the considered AF relay network
Performance study of an underlay cognitive radio network in the presence of co-channel interference
PhD ThesisMassive innovation in all aspects of the wireless communication network
has been witnessed over the last few decades. The demand for data
throughput is continuously growing, as such, the current regulations for
allocating frequency spectrum are not able to respond to this exponential growth. Cognitive radio (CR), has been proposed as a solution to
this problem. One of the possible scenarios of the implementation of CR
is underlay cognitive radio. In this thesis the performance of an underlay cognitive radio network (UCRN) in the presence of the co-channel
interference (CCI) is assessed.
Firstly, the impact of CCI on the dual-hop cooperative UCRN is investigated over Rayleigh fading channels. In order to do this, the exact outage
probability (OP), average error probability (AEP) and the ergodic capacity (EC) are studied. In addition, simple and asymptotic expressions
for the OP and AEP are derived. Furthermore, the optimal power allocation is investigated to enhance the network performance. Moreover,
the performance of a multi-user scenario is studied by considering the
opportunistic SNR-based selection technique.
Secondly, the effect of both primary network interference and CCI on
the dual-hop UCRN over Rayleigh fading channels are studied. The
equivalent signal-to-interference-plus-noise ratio (SINR) for this network
scenario is obtained by considering multi-antenna schemes at all receiver
nodes. The different signal combinations at the receiver nodes are investigated and compared, such as selection combining (SC) and maximum
ratio combining (MRC) techniques. Then, the equivalent probability
density function (PDF) and cumulative distribution function (CDF) of
the network’s equivalent SINR are derived and discussed. Furthermore,
expressions for the exact OP, AEP, and EC are derived and reviewed.
In addition, asymptotic OP expressions are obtained for different case
scenarios to gain an insight into the network parameters.
Thirdly, multiple-input multiple-output (MIMO) UCRN is investigated
under the influence of primary transmitter interference and CCI over
Rayleigh fading channels. The transmit antenna selection and maximum
ratio combining (TAS/MRC) techniques are considered for examining
the performance of the secondary network. At first the equivalent SINR
for the system is derived, then the exact and approximate expressions
for the OP are derived and discussed.
Fourthly, considering Nakagami-m fading channels, the performance of
the UCRN is thoroughly studied with the consideration of the impact
of primary network interference and CCI. The equivalent SINR for the
secondary system is derived. Then, the system equivalent PDF and CDF
are derived and discussed. Furthermore, the OP and AEP performances
are investigated.
Finally, for the cases mentioned above, numerical examples in conjunction with MatLab Monte Carlo simulations are provided to validate the
derived results. The results show that CCI is one of the factors that
severely reduces the UCRN performance. This can be more observable
when the CCI power increases linearly with the transmission power of
the secondary transmitter nodes. Furthermore, it was found that in
a multi-user scenario the opportunistic SNR-based selection technique
consideration can improve the performance of the network. Moreover,
adaptive power allocation is found to give better results than equal power
allocation. In addition, cooperative communication can be considered to
be an effective way to combat the impact of transmission power limitation of the secondary network and interference power constraint. The
multi-antenna schemes are another important consideration for enhancing the overall performance. In fact, despite the interference from the
CCI and primary user sources, the multi-antennas scheme does not lose
its advantage in the UCRN performance improvementHigher Committee for Education Development in Iraq (HCED). I am also grateful to
the Ministry of Transportation and Communication, Kurdistan Regional
Government-Iraq
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
Hybrid satellite–terrestrial networks toward 6G : key technologies and open issues
Future wireless networks will be required to provide more wireless services at higher data rates and with global coverage. However, existing homogeneous wireless networks, such as cellular and satellite networks, may not be able to meet such requirements individually, especially in remote terrain, including seas and mountains. One possible solution is to use diversified wireless networks that can exploit the inter-connectivity between satellites, aerial base stations (BSs), and terrestrial BSs over inter-connected space, ground, and aerial networks. Hence, enabling wireless communication in one integrated network has attracted both the industry and the research fraternities. In this work, we provide a comprehensive survey of the most recent work on hybrid satellite–terrestrial networks (HSTNs), focusing on system architecture, performance analysis, design optimization, and secure communication schemes for different cooperative and cognitive HSTN network architectures. Different key technologies are compared. Based on this comparison, several open issues for future research are discussed