Performance of a Free-Space-Optical Relay-Assisted Hybrid RF/FSO System in Generalized <inline-formula> <tex-math notation="LaTeX">$M$</tex-math></inline-formula>-Distributed Channels
This paper investigates the average symbol error rate (ASER) performance of a dual-hop hybrid relaying system relying on both radio frequency (RF) and free-space optical (FSO) links. Specifically, an RF link is used for supporting mobile communication, whereas an FSO link is adopted as the backhaul...
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| Format: | Article |
| Language: | English |
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IEEE
2015-01-01
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| Series: | IEEE Photonics Journal |
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| Online Access: | https://ieeexplore.ieee.org/document/7210140/ |
| _version_ | 1818718084068802560 |
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| author | Lei Kong Wei Xu Lajos Hanzo Hua Zhang Chunming Zhao |
| author_facet | Lei Kong Wei Xu Lajos Hanzo Hua Zhang Chunming Zhao |
| author_sort | Lei Kong |
| collection | DOAJ |
| description | This paper investigates the average symbol error rate (ASER) performance of a dual-hop hybrid relaying system relying on both radio frequency (RF) and free-space optical (FSO) links. Specifically, an RF link is used for supporting mobile communication, whereas an FSO link is adopted as the backhaul of the cellular infrastructure. Considering nonline-of-sight RF transmissions and a generalized atmospheric turbulence (AT) channel, the associated statistical features constituted of both exact and asymptotic moment-generating functions are derived in the closed form. They are then used for calculating the ASER of M-ary phase-shift keying (PSK), differentially encoded noncoherent PSK (DPSK), and noncoherent frequency-shift keying. A range of additional asymptotic expressions is also derived for all the modulation schemes under high signal-to-noise ratios (SNR). It is observed from the asymptotic analysis that the ASERs of all the modulation schemes are dominated by the average SNR of the RF link in the hybrid relaying system using a fixed relay gain, whereas in the relaying system using a dynamic channel-dependent relay gain, the ASERs of all the modulation schemes depend both on the average SNR and the AT condition of the FSO path. We also find that the fixed-gain relaying strategy achieves twice the diversity order of the channel-dependent relaying strategy, albeit at the cost of requiring a high power amplifier dynamic range at the relay node. Furthermore, by comparing the asymptotic ASERs, we calculate the SNR differences between the different modulation schemes in both the fixed-gain and channel-dependent relaying systems. Finally, simulation results are presented for confirming the accuracy of our expressions and observations. |
| first_indexed | 2024-12-17T19:45:25Z |
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| id | doaj.art-f29af51e2d1049ccae15b361a9d7d9a0 |
| institution | Directory Open Access Journal |
| issn | 1943-0655 |
| language | English |
| last_indexed | 2024-12-17T19:45:25Z |
| publishDate | 2015-01-01 |
| publisher | IEEE |
| record_format | Article |
| series | IEEE Photonics Journal |
| spelling | doaj.art-f29af51e2d1049ccae15b361a9d7d9a02022-12-21T21:34:53ZengIEEEIEEE Photonics Journal1943-06552015-01-017511910.1109/JPHOT.2015.24701067210140Performance of a Free-Space-Optical Relay-Assisted Hybrid RF/FSO System in Generalized <inline-formula> <tex-math notation="LaTeX">$M$</tex-math></inline-formula>-Distributed ChannelsLei Kong0Wei Xu1Lajos Hanzo2Hua Zhang3Chunming Zhao4Nat. Mobile Commun. Res. Lab., Southeast Univ., Nanjing, ChinaNat. Mobile Commun. Res. Lab., Southeast Univ., Nanjing, ChinaSch. of Electron. & Comput. Sci. (ECS), Univ. of Southampton, Southampton, UKNat. Mobile Commun. Res. Lab., Southeast Univ., Nanjing, ChinaNat. Mobile Commun. Res. Lab., Southeast Univ., Nanjing, ChinaThis paper investigates the average symbol error rate (ASER) performance of a dual-hop hybrid relaying system relying on both radio frequency (RF) and free-space optical (FSO) links. Specifically, an RF link is used for supporting mobile communication, whereas an FSO link is adopted as the backhaul of the cellular infrastructure. Considering nonline-of-sight RF transmissions and a generalized atmospheric turbulence (AT) channel, the associated statistical features constituted of both exact and asymptotic moment-generating functions are derived in the closed form. They are then used for calculating the ASER of M-ary phase-shift keying (PSK), differentially encoded noncoherent PSK (DPSK), and noncoherent frequency-shift keying. A range of additional asymptotic expressions is also derived for all the modulation schemes under high signal-to-noise ratios (SNR). It is observed from the asymptotic analysis that the ASERs of all the modulation schemes are dominated by the average SNR of the RF link in the hybrid relaying system using a fixed relay gain, whereas in the relaying system using a dynamic channel-dependent relay gain, the ASERs of all the modulation schemes depend both on the average SNR and the AT condition of the FSO path. We also find that the fixed-gain relaying strategy achieves twice the diversity order of the channel-dependent relaying strategy, albeit at the cost of requiring a high power amplifier dynamic range at the relay node. Furthermore, by comparing the asymptotic ASERs, we calculate the SNR differences between the different modulation schemes in both the fixed-gain and channel-dependent relaying systems. Finally, simulation results are presented for confirming the accuracy of our expressions and observations.https://ieeexplore.ieee.org/document/7210140/Relayatmospheric turbulencefree space optical communicationssymbol error ratehybrid RF/FSO |
| spellingShingle | Lei Kong Wei Xu Lajos Hanzo Hua Zhang Chunming Zhao Performance of a Free-Space-Optical Relay-Assisted Hybrid RF/FSO System in Generalized <inline-formula> <tex-math notation="LaTeX">$M$</tex-math></inline-formula>-Distributed Channels IEEE Photonics Journal Relay atmospheric turbulence free space optical communications symbol error rate hybrid RF/FSO |
| title | Performance of a Free-Space-Optical Relay-Assisted Hybrid RF/FSO System in Generalized <inline-formula> <tex-math notation="LaTeX">$M$</tex-math></inline-formula>-Distributed Channels |
| title_full | Performance of a Free-Space-Optical Relay-Assisted Hybrid RF/FSO System in Generalized <inline-formula> <tex-math notation="LaTeX">$M$</tex-math></inline-formula>-Distributed Channels |
| title_fullStr | Performance of a Free-Space-Optical Relay-Assisted Hybrid RF/FSO System in Generalized <inline-formula> <tex-math notation="LaTeX">$M$</tex-math></inline-formula>-Distributed Channels |
| title_full_unstemmed | Performance of a Free-Space-Optical Relay-Assisted Hybrid RF/FSO System in Generalized <inline-formula> <tex-math notation="LaTeX">$M$</tex-math></inline-formula>-Distributed Channels |
| title_short | Performance of a Free-Space-Optical Relay-Assisted Hybrid RF/FSO System in Generalized <inline-formula> <tex-math notation="LaTeX">$M$</tex-math></inline-formula>-Distributed Channels |
| title_sort | performance of a free space optical relay assisted hybrid rf fso system in generalized inline formula tex math notation latex m tex math inline formula distributed channels |
| topic | Relay atmospheric turbulence free space optical communications symbol error rate hybrid RF/FSO |
| url | https://ieeexplore.ieee.org/document/7210140/ |
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