| 1. |
- Tran, Thi-Thuy-Quynh, et al.
(författare)
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Network Coding with Multimedia Transmission and Cognitive Networking: An Implementation based on Software-Defined Radio
- 2020
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Ingår i: REV Journal on Electronics and Communications. ; 10:3-4, s. 72-84
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Tidskriftsartikel (refereegranskat)abstract
- Network coding (NC) is considered a breakthrough to improve throughput, robustness, and security of wireless networks. Although the theoretical aspects of NC have been extensively investigated, there have been only few experiments with pure NC schematics. This paper presents an implementation of NC under a two-way relay model and extends it to two non-straightforward scenarios: (i) multimedia transmission with layered coding and multiple-description coding, and (ii) cognitive radio with Vandermonde frequency division multiplexing (VFDM). The implementation is in real time and based on software-defined radio (SDR). The experimental results show that, by combining NC and source coding, we can control the quality of the received multimedia content in an on-demand manner. Whereas in the VFDM-based cognitive radio, the quality of the received content in the primary receiver is low (due to imperfect channel estimation) yet retrievable. Our implementation results serve as a proof for the practicability of network coding in relevant applications.
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| 2. |
- Duong, Quang Trung, et al.
(författare)
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Ergodic Capacity of Cooperative Networks Using Adaptive Transmission and Selection Combining
- 2009
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Konferensbidrag (refereegranskat)abstract
- Closed-form expressions for channel capacity of repetition-based cooperative networks under adaptive transmission with selection combining are presented under the assumption of independent Rayleigh fading. Specifically, three different adaptive techniques are investigated: optimal simultaneous power and rate adaptation (OPRA), constant power with optimal rate adaptation (OPA) and channel inversion with fixed rate (TIFR). Among them, for an arbitrary number of relays, TIFR gives the worst channel capacity; OPRA gives the best channel capacity and ORA has a channel capacity quality in between the others. The analysis results, based on the upper and lower bound of the end-to-end SNR, agree very well with the simulated results and definitely show the impact of selection combining on the calculated channel capacity per unit bandwidth
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| 3. |
- Al-Qahtani, Fawaz S., et al.
(författare)
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Selection Decode-and-Forward Relay Networks with Rectangular QAM in Nakagami-m Fading Channels
- 2010
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Konferensbidrag (refereegranskat)abstract
- In this paper, we investigate the average symbol error probability (SEP) of fixed decode-and-forward relay networks over independent but not identically distributed Nakagami-m fading channels. We have derived closed form expression of SEP for general rectangular quadrature amplitude modulation (QAM) under relay selection scheme where only the best relay forwards message from the source to the destination. The expressions are in terms of hypergeometric series which can be efficiently numerically evaluated. The numerical results are validated with Monte-Carlo simulations.
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| 4. |
- Bao, Vo Nguyen Quoc, et al.
(författare)
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Cognitive Amplify-and-Forward Relaying with Best Relay Selection in Non-Identical Rayleigh Fading
- 2013
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Ingår i: IEEE Communications Letters. - : IEEE. - 1089-7798 .- 1558-2558. ; 17:3, s. 475-478
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates several important performance metrics of cognitive amplify-and-forward (AF) relay networks with a best relay selection strategy and subject to nonidentical Rayleigh fading. In particular, assuming a spectrum sharing environment consists of one secondary user (SU) source,K SU relays, one SU destination, and one primary user (PU) receiver, closed-form expressions for the outage probability (OP), average symbol error probability (SEP), and ergodic capacity of the SU network are derived. The correctness of the proposed analysis is corroborated via Monte Carlo simulations and readily allows us to evaluate the impact of the key system parameters on the end-to-end performance. An asymptotic analysis is also carried out and reveals that the diversity gain is defined by the number of relays pertaining to the SU network (i.e., K), being therefore not affected by the interference power constraint of the PU network.
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| 5. |
- Bao, Vo Nguyen Quoc, et al.
(författare)
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Distributed Switch-and-Stay Combining in Cognitive Relay Networks under Spectrum Sharing Constraints
- 2013
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Ingår i: 2013 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM). - : IEEE Communications Society. - 9781479913534 ; , s. 1927-1932
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Konferensbidrag (refereegranskat)abstract
- Distributed switch-and-stay combining (DSSC) has been envisioned as an effective transmission technique to achieve spatial diversity in a distributed fashion, with low implementation complexity. In this paper, we take a step further to incorporate DSSC into spectrum-limited environment, where the operating nodes have to share the frequency radio spectrum with licensed users. In particular, by deploying DSSC scheme in cognitive radio networks, we have shown that the low transmit power at unlicensed users, inflicted by the peak interference power constraint at licensed users, can be alleviated. We present closed-form expressions for outage probability and spectral efficiency, enabling us to evaluate and optimize the considered network performance. Numerical and simulation results show that when the switching threshold is below the outage threshold the full diversity order can be guaranteed at the secondary networks.
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| 6. |
- Bao, Vo Nguyen Quoc, et al.
(författare)
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Effect of Imperfect Channel State Information on the Performance of Cognitive Multihop Relay Networks
- 2013
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Ingår i: 2013 IEEE GLOBAL COMMUNICATIONS CONFERENCE (GLOBECOM). - 9781479913534 ; , s. 3458-3463
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Konferensbidrag (refereegranskat)abstract
- Cognitive relay technology has been envisioned as a promising transmission scheme to enhance the reliability and coverage of secondary networks. However, the performance of cognitive relay networks (CRNs) is limited by the lack of accurate channel state information (CSI). As such, this paper adequately addresses the impact of imperfect CSI on the performance of cognitive multihop networks by proposing a simple yet effective backoff control power method. In addition, novel exact and asymptotic expressions for outage probability and ergodic capacity over Rayleigh fading channels are also derived. These tractable analytical results reveal new insight into the design, e.g., the number of hops for secondary network, and optimization of cognitive multihop networks.
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| 7. |
- Bao, Vo Nguyen Quoc, et al.
(författare)
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Exact Outage Probability of Cognitive Underlay DF Relay Networks with Best Relay Selection
- 2012
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Ingår i: IEICE transactions on communications. - : IEICE. - 0916-8516 .- 1745-1345. ; E95-B:6, s. 2169-2173
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Tidskriftsartikel (refereegranskat)abstract
- In this letter, we address the performance analysis of underlay selective decode-and-forward (DF) relay networks in Rayleigh fading channels with non-necessarily identical fading parameters. In particular, a novel result on the outage probability of the considered system is presented. Monte Carlo simulations are performed to verify the correctness of our exact closed-form expression. Our proposed analysis can be adopted for various underlay spectrum sharing applications of cognitive DF relay networks.
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| 8. |
- Bao, Vo Nguyen Quoc, et al.
(författare)
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On the performance of cognitive underlay multihop networks with imperfect channel state information
- 2013
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Ingår i: IEEE Transactions on Communications. - : IEEE. - 0090-6778 .- 1558-0857. ; 61:12, s. 4864-4873
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes and analyzes cognitive multihop decode-and-forward networks in the presence of interference due to channel estimation errors. To reduce interference on the primary network, a simple yet effective back-off control power method is applied for secondary multihop networks. For a given threshold of interference probability at the primary network, we derive the maximum back-off control power coefficient, which provides the best performance for secondary multihop networks. Moreover, it is shown that the number of hops for secondary network is upper-bounded under the fixed settings of the primary network. For secondary multihop networks, new exact and asymptotic expressions for outage probability (OP), bit error rate (BER) and ergodic capacity over Rayleigh fading channels are derived. Based on the asymptotic OP and BEP, a pivotal conclusion is reached that the secondary multihop network offers the same diversity order as compared with the network without back off. Finally, we verify the performance analysis through various numerical examples which confirm the correctness of our analysis for many channel and system settings and provide new insight into the design and optimization of cognitive multihop networks.
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| 9. |
- Bao, Vo Nguyen Quoc, et al.
(författare)
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Outage Analysis of Cognitive Multihop Networks under Interference Constraints
- 2012
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Ingår i: IEICE transactions on communications. - : IEICE. - 0916-8516 .- 1745-1345. ; E95-B:3
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Tidskriftsartikel (refereegranskat)abstract
- The closed-form expressions for outage probability, bit error rate, and ergodic capacity of spectrum sharing-based multi-hop decode-and-forward relay networks in non-identical Rayleigh fading channels are derived. Utilizing these precise and tractable analytical formulas, we can study the impact of key network parameters on the performance of cognitive multi-hop relay networks under interference constraints. The analytical expressions are verified by Monte-Carlo simulations.
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| 10. |
- Duong, Quang Trung, et al.
(författare)
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Amplify-and-Forward MIMO Relaying with OSTBC over Nakagami-m Fading Channels
- 2010
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Konferensbidrag (refereegranskat)abstract
- In this paper, we analyze the performance of dual-hop channel state information (CSI)-assisted amplify-andforward (AF) cooperative networks using orthogonal space-time block codes (OSTBCs) over independent but not identically distributed Nakagami-m fading channels. Specifically, we present closed-form expressions of the outage probability (OP) and the symbol error probability (SEP). The analytical results are given in tractable forms which readily allow us to assess the performance of AF relay systems using OSTBCs. For sufficiently large signal-to-noise ratio, we obtain the asymptotic results for OP and SEP which reveal insights into the effect of fading factors on the diversity and coding gains. It has been shown that between the two hops the more severe link solely determines the diversity and coding gains. In particular, these two gains strictly depend on the fading severity parameters and the channel mean powers of the more rigorous hop, respectively. Numerical results are provided showing an excellent agreement between our analytical results and those of Monte-Carlo simulations for selected scenarios.
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| 11. |
- Duong, Quang Trung, et al.
(författare)
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Cognitive Amplify-and-Forward Relay Networks over Nakagami-m Fading
- 2012
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Ingår i: IEEE Transactions on Vehicular Technology. - : IEEE. - 0018-9545 .- 1939-9359. ; 61:5, s. 2368-2374
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Tidskriftsartikel (refereegranskat)abstract
- In this correspondence, the outage probability (OP) of dual-hop cognitive amplify-and-forward (AF) relay networks subject to independent non-identically distributed (i.n.i.d.) Nakagami-m fading is examined. We assume a spectrum sharing environment, where two different strategies are proposed for determining the transmit powers of the secondary network. Specifically, the transmit power conditions of the proposed spectrum sharing network are governed by either: (i) the combined power constraint of the interference on the primary network and maximum transmission power at the secondary network; or (ii) the single power constraint of the interference on the primary network. Closed-form lower bounds and asymptotic expressions for the OP are derived. Regardless of the transmit power constraint, we reveal that the diversity order is strictly defined by the minimum fading severity between the two hops of the secondary network. This aligns with the well-known result for conventional dual-hop AF relaying without spectrum sharing. Furthermore, the impact of the primary network on the diversity-multiplexing tradeoff is investigated. We confirm that the diversity-multiplexing tradeoff is independent of the primary network.
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| 12. |
- Duong, Quang Trung, et al.
(författare)
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Cognitive Relay Networks With Multiple Primary Transceivers Under Spectrum-Sharing
- 2012
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Ingår i: IEEE Signal Processing Letters. - : IEEE. - 1070-9908 .- 1558-2361. ; 19:11, s. 741-744
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Tidskriftsartikel (refereegranskat)abstract
- We examine the impact of multiple primary transmitters and receivers (PU-TxRx) on the outage performance of cognitive decode-and-forward relay networks. In such a joint relaying/spectrum-sharing arrangement, we address fundamental questions concerning three key power constraints: 1) maximum transmit power at the secondary transmitter (SU-Tx), 2) peak interference power at the primary receivers (PU-Rx), and 3) interference power at SU-Rx caused by the primary transmitter (PU-Tx). Our answers to these are given in new analytical expressions for the exact and asymptotic outage probability of the secondary relay network. Based on our asymptotic expressions, important design insights into the impact of primary transceivers on the performance of cognitive relay networks is reached. We have shown that zero diversity order is attained when the peak interference power at the PU-Rx is independent of the maximum transmit power at the SU-TX.
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| 13. |
- Duong, Quang Trung, et al.
(författare)
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Cooperative spectrum sharing networks with AF relay and selection diversity
- 2011
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology - IET. - 0013-5194 .- 1350-911X. ; 47:20, s. 1149-1151
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Tidskriftsartikel (refereegranskat)abstract
- The exact outage probability (OP) of cognitive dual-hop relay networks equipped with a single amplify-and-forward (AF) relay and a selection combining receiver at the destination is derived under spectrum sharing constraint on a primary user. The tractable closed-form OP readily enables evaluation of system performance, which indicates the significance of using a relay in cognitive radio networks with a spectrum sharing approach. The proposed analysis is validated by numerical examples.
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| 14. |
- Duong, Quang Trung, et al.
(författare)
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Effect of primary network on performance of spectrum sharing AF relaying
- 2012
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Ingår i: Electronics Letters. - : IET. - 0013-5194 .- 1350-911X. ; 48:1, s. 25-U95
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Tidskriftsartikel (refereegranskat)abstract
- Most of the research in spectrum sharing has neglected the effect of interference from primary users. In this reported work, the performance of spectrum sharing amplify-and-forward relay networks under interference-limited environment, where the interference induced by the transmission of primary networks is taken into account, is investigated. In particular, a closed-form expression tight lower bound of outage probability is derived. To reveal additional insights into the effect of primary networks on the diversity and array gains, an asymptotic expression is also obtained.
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| 15. |
- Duong, Quang Trung, et al.
(författare)
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Exact outage probability of cognitive AF relaying with underlay spectrum sharing
- 2011
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology -IET. - 0013-5194 .- 1350-911X. ; 47:17, s. 1001-1002
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Tidskriftsartikel (refereegranskat)abstract
- The exact closed-form expression for the outage probability (OP) of cognitive radio dual-hop amplify-and-forward (AF) relay networks is derived. The tractable expression of the OP, given in the form of elementary functions, readily enables evaluating the effect of primary users on the secondary system performance. It has been shown that the use of AF relaying significantly improves the performance of cognitive radio networks compared to its direct transmission counterpart.
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| 16. |
- Duong, Quang Trung, et al.
(författare)
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On the Performance of Selection Decode-and-Forward Relay Networks over Nakagami-m Fading Channels
- 2009
-
Ingår i: IEEE Communications Letters. - 1089-7798 .- 1558-2558. ; 13:3, s. 172-174
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present the performance of fixed decode-and-forward cooperative networks with relay selection over independent but not identically distributed Nakagamim fading channels, with integer values of the fading severity parameter m. Specifically, closed-form expressions for the symbol error probability and the outage probability are derived using the statistical characteristic of the signal-to-noise ratio. We also perform Monte-Carlo simulations to verify the analytical results
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| 17. |
- Duong, Quang Trung, et al.
(författare)
-
On the Performance of Two-Way Amplify-and-Forward Relay Networks
- 2009
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Ingår i: IEICE transactions on communications. - : IEICE. - 0916-8516 .- 1745-1345. ; E92-B:12, s. 3957-3959
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Tidskriftsartikel (refereegranskat)abstract
- The performance of two-way amplify-and-forward (AF) relay networks is presented. In particular, we derive exact closed-form expressions for symbol error rate (SER), average sum-rate, and outage probability of two-way AF relay systems in independent but not identically distributed (i.n.i.d.) Rayleigh fading channels. Our analysis is validated by a comparison against the results of Monte-Carlo simulations.
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| 18. |
- Duong, Quang Trung, et al.
(författare)
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Performance Analysis of Amplify-and-Forward MIMO Relay Networks with Transmit Antenna Selection over Nakagami-m Channels
- 2010
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Konferensbidrag (refereegranskat)abstract
- We analyze the performance of amplify-and-forward (AF) multiple-input multiple-output (MIMO) cooperative networks over independent but not identically distributed Nakagami-$m$ fading channels. Specifically, we consider an AF MIMO relay network where the source deploys the transmit antenna selection scheme to communicate with the destination through the help of a relay. We derive closed-form approximations for outage probability (OP) and symbol error probability (SEP). Moreover, asymptotically tight approximations for OP and SEP have been obtained to facilitate insights on how fading parameters affect the performance. Our analytical results are verified by Monte-Carlo simulations for respective scenarios.
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| 19. |
- Duong, Quang Trung, et al.
(författare)
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Performance analysis of cooperative spatial multiplexing networks with AF/DF relaying and linear receiver over Rayleigh fading channels
- 2015
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Ingår i: Wireless Communications & Mobile Computing. - : Elsevier. - 1530-8669 .- 1530-8677. ; 15:3, s. 500-509
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Tidskriftsartikel (refereegranskat)abstract
- Cooperative spatial multiplexing (CSM) system has played an important role in wireless networks by offering a substantial improvement in multiplexing gain compared with its cooperative diversity counterpart. However, there is a limited number of research works that consider the performance of CSM systems. As such, in this paper, we have derived exact performance of CSM with amplify-and-forward and decode-and-forward relays in terms of outage capacity and ergodic capacity. We have shown that CSM systems yield a unity diversity order regardless of the number of antennas at the destination and the number of relays in the networks, which is the direct result of diversity and multiplexing gain trade-off. Our analytical expressions are corroborated by Monte-Carlo simulations.
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| 20. |
- Duong, Quang Trung, et al.
(författare)
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Performance Analysis of Selection Decode-and-Forward Relay Networks
- 2008
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Ingår i: Electronics Letters. - : The Institute of Engineering and Technology. - 0013-5194 .- 1350-911X. ; 44:20, s. 1206-07
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Tidskriftsartikel (refereegranskat)abstract
- The performance of decode-and-forward (DF) cooperative networks with relay selection is presented. Specifically, we derive closed-form expressions for symbol error probability (SEP), bit error rate (BER), and achievable spectral efficiency of DF relay selection system in independent but not identically distributed (i.n.i.d.) Rayleigh fading channels taking into account the incapability of decoding the received signals' cyclic redundancy code (CRC) at the relays. We also perform Monte-Carlo simulations to validate the analysis.
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| 21. |
- Duong, Quang Trung, et al.
(författare)
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Symbol error probability of hop-by-hop beamforming in Nakagami-m fading
- 2009
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Ingår i: Electronics Letters. - : The Institution of Engineering and Technology. - 0013-5194 .- 1350-911X. ; 45:20, s. 1042-1044
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Tidskriftsartikel (refereegranskat)abstract
- The symbol error probability (SEP) of amplify-and-forward(AF) multiple-input multiple-output (MIMO) cooperative networks where beamforming is adopted at both the source and destination is investigated. In particular, the tight lower bound for SEP of AF MIMO relay systems is presented with hop-by-hop beamforming over independent, but not necessarily identically distributed, Nakagami-m fading channels. Furthermore, assessing the high SNR, an asymptotic SEP expression is derived which reveals the array and diversity gain. Numerical results are shown to verify the analysis in some representative scenarios.
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| 22. |
- Kim, Kyeongjin, et al.
(författare)
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Cognitive multihop networks in spectrum sharing environment with multiple licensed users
- 2013
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Konferensbidrag (refereegranskat)abstract
- Multihop network has been considered as a breakthrough frontier to enhance the coverage of wireless network. Spectrum-sharing is an efficient technique to enhance the utilization of the limited radio frequency bandwidth. In this paper, we therefore consider the extension of multihop network to cognitive radio networks with the spectrum sharing approach. In particular, we investigate the cognitive multihop networks in the presence of multiple licensed transmitters and receivers. Under the stringent power constraint imposed by the licensed users, we derive the closed-form and asymptotic expressions for the outage probability over Nakagami-m fading channels. The tractable closed-form expressions reveal the impact of important network parameters such as the fading severity parameters of the unlicensed network, the number of licensed users, the peak interference power imposed by the licensed receivers, the interference power from licensed transmitters. A significant observation corroborated by our study shows that the cognitive multihop networks benefit both cognitive radio and multihop networks for improving the coverage extension and frequency spectrum utilization.
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| 23. |
- Tran, Thien Thanh, et al.
(författare)
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Performance analysis and optimal relay position of cognitive spectrum-sharing dual-hop decode-and-forward networks
- 2013
-
Konferensbidrag (refereegranskat)abstract
- The performance of cognitive networks (CNs) has been significantly improved by deploying a third-party, namely relay, to assist the direct communication. However, under a limited transmit power governed by the maximum tolerable interference at the primary network, the cognitive relay network still suffers a performance loss compared to its non-cognitive counterpart. To alleviate this shortcoming, this paper has pro-posed a technique to optimally deploy the relay in CNs. In particular, by assuming the decode-and-forward (DF) relay, we first derive an exact expression for the outage probability (OP) of CNs with spectrum-sharing environment over Nakagami-m channels. Then, using the exact formula, we obtain the asymptotic OP expression which further reveals the impact of networks' parameters on the performance. In addition, the optimal relay placement, i.e., minimizing the system OP, is also investigated by utilizing the asymptotic OP result. We have shown through some representative scenarios that given a fixed coordinate of a primary receiver, the optimal relay deployment significantly outperforms the two conventional approaches, i.e., uniform and random topologies.
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