1. Gabatarwa

Wannan takarda tana binciken tsarin Sadarwar Haske Mai Gani (VLC) na Non-Orthogonal Multiple Access (NOMA) wanda aka inganta ta Masu Karɓar Bambance-bambancen Karkata (ADRs). Babban ƙalubalen da aka magance shine iyakancewar tsarin VLC na al'ada wajen samar da manyan ƙimar bayanai saboda dalilai kamar Tsangwama Tsakanin Alamomi (ISI) da Tsangwama Tashoshi Guda (CCI). Tsarin da aka gabatar ya haɗa ingantaccen amfani da mitar NOMA tare da ikon rage tsangwama da kama siginar na ADR mai reshe 4, da nufin haɓaka ƙimar bayanan mai amfani a cikin yanayin cikin gida.

2. Tsarin Tsarin

An ƙirƙira tsarin a cikin wani daki mara komai mai girman 8m × 4m × 3m. Tashar gani ta haɗa da hasashe daga bango da rufi, wanda aka ƙirƙira a matsayin masu hasashe na Lambertian tare da ma'aunin hasashe (ρ) na 0.8. Ana amfani da bin haske don kwaikwayon yaduwar siginar haske ta hanyoyi da yawa.

2.1 Ƙirar Daki da Tashoshi

Ana ƙididdige amsawar motsa jiki na tashar cikin gida yana la'akari da abubuwan gani kai tsaye (LOS) da naɓaɓɓa (hasashe). An raba saman masu hasashe zuwa ƙananan abubuwa na yanki dA. Ribar DC ta tashar don mai karɓa tare da yankin mai gano $A_{pd}$ da riba $T_s(\psi)$ ana bayar da ita kamar haka:

$H(0) = \frac{(m+1)A_{pd}}{2\pi d^2} \cos^m(\phi) T_s(\psi) g(\psi) \cos(\psi)$ don $0 \le \psi \le \Psi_c$

inda $m$ shine tsari na Lambertian, $d$ nesa, $\phi$ kusurwar haske, $\psi$ kusurwar faɗuwa, kuma $\Psi_c$ shine filin gani (FOV) na mai karɓa.

2.2 Ƙirar Mai Karɓar Bambance-bambancen Karkata (ADR)

ADR ya ƙunshi masu gano hoto guda huɗu masu kunkuntar FOV, kowanne yana fuskantar wata hanya daban (misali, zuwa kusurwoyin daki ko takamaiman wuraren shiga). Wannan ƙira tana ba mai karɓa damar zaɓar reshe mafi ƙarfin ma'aunin siginar zuwa amo (SNR) ko haɗa siginar, yana rage tasirin hasken muhalli, tarwatsewar hanyoyi da yawa, da tsangwama tashoshi guda yadda ya kamata.

2.3 Ka'idar NOMA da Rarraba Wutar Lantarki

NOMA yana aiki ta hanyar haɗa siginar masu amfani da yawa a cikin yankin wutar lantarki a wurin mai aikawa. A wurin mai karɓa, ana amfani da Soke Tsangwama na Bi-da-Bi (SIC) don ɓoye siginar. Ana rarraba wutar lantarki akasin ribar tashar: masu amfani da suke da mafi kyawun yanayin tashar (siginar mafi ƙarfi) ana ba su ƙaramin wutar lantarki, yayin da masu amfani da suke da mafi munin yanayi suka sami ƙarin wutar lantarki don tabbatar da adalci. Ƙimar da mai amfani $i$ zai iya samu ita ce:

$R_i = B \log_2 \left(1 + \frac{P_i |h_i|^2}{\sum_{j>i} P_j |h_i|^2 + \sigma^2}\right)$

inda $B$ faɗin band, $P_i$ wutar lantarki da aka ware wa mai amfani $i$, $h_i$ ribar tashar, kuma $\sigma^2$ bambancewar amo.

3. Sakamakon Siminti & Tattaunawa

Ana kwatanta aikin tsarin NOMA-VLC tare da ADR da tsarin tushe ta amfani da mai karɓa guda ɗaya mai faɗin FOV.

3.1 Kwatancen Aiki: ADR vs. Wide FOV

Babban binciken shine cewa tsarin tushen ADR ya sami haɓakar matsakaicin ƙimar bayanai na 35% sama da tsarin mai karɓa na Wide-FOV. An samo wannan ribar ne saboda ikon ADR na zaɓe kama siginar mafi ƙarfi, ƙasa da murdiya da kuma ƙi abubuwan tsangwama daga wasu masu aikawa ko hasashe.

3.2 Binciken Ƙimar Bayanai da Ingantawa

Simintin ya ƙunshi inganta rarraba albarkatu (wutar lantarki) tsakanin masu amfani bisa yanayin tasharsu na nan take, wanda aka samo daga zaɓin reshen ADR. Ingantawar tana da nufin haɓaka jimillar ƙimar bayanai yayin kiyaye adalcin mai amfani, bin tsarin da marubutan suka yi a baya [36]. Sakamakon ya nuna cewa haɗuwar zaɓin reshe mai daidaitawa da rarraba wutar lantarki ta NOMA suna haɓaka ingantaccen amfani da mitar sosai.

Mahimmin Ma'aunin Aiki

35% Matsakaicin Ribar Ƙimar Bayanai da tsarin NOMA-VLC na tushen ADR ya samu idan aka kwatanta da tsarin tushen mai karɓa na Wide-FOV.

4. Ƙarshe

Takardar ta ƙarasa da cewa haɗa Masu Karɓar Bambance-bambancen Karkata tare da NOMA a cikin tsarin VLC wata dabarar da ta yi tasiri sosai don shawo kan manyan iyakoki kamar tsangwama da ƙarancin faɗin band. ADR mai reshe 4 yana ba da riba mai yawa a cikin ƙimar bayanai ta hanyar inganta ingancin siginar da ba da damar ƙarin ingantaccen rarraba wutar lantarki ta masu amfani da yawa ta hanyar NOMA. Wannan aikin ya tabbatar da yuwuwar ƙirar mai karɓa mai ci gaba da haɗe tare da haɗawa mara kai tsaye don cibiyoyin sadarwar wayar mara waya ta gani na gaba.

5. Cikakkiyar Fahimtar Mai Bincike

Cikakkiyar Fahimta: Wannan takarda ba kawai game da ɗan ƙaramin ci gaba ba ce; juyawa ce ta dabarun. Ta gano daidai cewa toshewar don VLC mai yawa, mai ƙarfi ba kawai mai aikawa ba ne (inda mafi yawan bincike ke mayar da hankali, misali, akan µLEDs ko diodes na Laser) amma a mahimminci, ikon mai karɓa na bambance siginar a cikin yanayi mai amo, mai hanyoyi da yawa. Ribar 35% daga ADR mai reshe 4 mai sauƙi shaida ce mai ƙarfi ga wannan girma da ake yawan yin watsi da shi.

Kwararar Ma'ana: Hujjar tana da inganci: 1) VLC tana fama da tsangwama (CCI/ISI), 2) ADRs suna rage tsangwama ta hanyar tace sararin samaniya, 3) Tsaftatattun siginar suna ba da damar haɗawa mai ƙarfi (NOMA), 4) Haɗawa ta yankin wutar lantarki na NOMA yana haɓaka ingantaccen amfani da mitar. Simintin a cikin ƙirar daki da aka daidaita (kama da waɗanda ƙungiyar aikin IEEE 802.15.7r1 ke amfani da su) yana ba da tabbaci mai inganci.

Ƙarfi & Kurakurai: Ƙarfin yana cikin haɗin gwiwar dabarun haɗa ra'ayoyi biyu masu girma (karɓar bambance-bambance da NOMA) don riba bayyananne, mai ƙima. Hanyar tana da ƙarfi. Duk da haka, kuskuren yana cikin sauƙin ƙirar ADR. ADRs na ainihi suna fuskantar ƙalubale kamar haɗin reshe, ƙarin rikitaccen kayan aikin, da buƙatar saurin, ƙananan wutar lantarki na zaɓin reshe algorithms — batutuwan da aka nuna kawai. Idan aka kwatanta da bincike na ƙarshe akan kayan aikin daidaitawa ko VLC na tushen MIMO ta amfani da masu karɓa masu ɗaukar hoto (kamar yadda aka gani a cikin ayyukan daga Lab na Media na MIT ko BWRC na UC Berkeley), wannan hanyar tana da sauƙin aiwatarwa amma tana iya samun ƙarancin iyakar iyakar ƙarshe.

Fahimta Mai Aiki: Ga masu sana'a a masana'antu, wannan takarda ita ce koren haske don saka hannun jari a cikin ƙirar mai karɓa. Manajojin samfur don Li-Fi ko tsarin VLC na masana'antu yakamata su ba da fifikon haɗa masu karɓa masu abubuwa da yawa. Ga masu bincike, matakai na gaba suna bayyananne: 1) Bincika koyon inji don zaɓin reshe na ADR mai ƙarfi, mai daidaitawa da haɗin mai amfani na NOMA. 2) Bincika haɗin kai tare da haɗawa ta rarraba tsawon zango (WDM) don riba mai yawa. 3) Guda gwaje-gwaje na ainihi tare da masu amfani na wayar hannu don tabbatar da aikin mai ƙarfi. Yin watsi da bambance-bambancen mai karɓa a cikin ƙa'idodin VLC na gaba zai zama babban kuskure.

6. Cikakkun Bayanai na Fasaha & Tsarin Lissafi

Babban gudummawar fasaha ita ce haɗin gwiwar inganta zaɓin reshen ADR da rarraba wutar lantarki ta NOMA. Siginar da aka karɓa a reshe na $k$ na ADR don mai amfani $i$ shine:

$y_{i,k} = h_{i,k} \sum_{u=1}^{U} \sqrt{P_u} x_u + n_{i,k}$

inda $h_{i,k}$ shine ribar tashar daga mai aikawa zuwa reshe na $k$ don mai amfani $i$, $P_u$ wutar lantarki da aka ware wa siginar mai amfani $u$ $x_u$, kuma $n_{i,k}$ shine ƙari farin amo na Gaussian. Mai karɓa yana zaɓar reshe $k^*$ don kowane mai amfani ko matakin ɓoyewa wanda ke haɓaka ingantaccen SNR. Tsarin SIC a mai amfani tare da ribar tashar $|h_i|^2$ yana ɓoye siginar a cikin tsari na haɓaka ribar tashar. Ma'aunin rarraba wutar lantarki $\alpha_i$ (inda $\sum \alpha_i = 1$, kuma $\alpha_i < \alpha_j$ idan $|h_i|^2 > |h_j|^2$) an inganta su don haɓaka jimillar ƙimar $\sum R_i$ ƙarƙashin ƙayyadaddun jimillar wutar lantarki $P_T$.

7. Sakamakon Gwaji & Bayanin Ginshiƙi

Yayin da takardar ta dogara ne akan siminti, sakamakon da aka bayyana ana iya gani ta hanyar manyan ginshiƙai:

  • Ginshiƙi 1: Jimillar Ƙimar vs. Wutar Aikawa: Wannan ginshiƙi zai nuna lanƙwasa biyu, ɗaya don tsarin ADR-NOMA da ɗaya don tushen Wide-FOV-NOMA. Dukansu lanƙwasan za su ƙaru da wutar lantarki, amma lanƙwasa na ADR zai nuna gangare mai gangare da faranti mafi girma, yana nuna ribar matsakaicin 35% a cikin kewayon wutar lantarki.
  • Ginshiƙi 2: Rarraba Ƙimar Mai Amfani: Ginshiƙi ko CDF yana nuna ƙimar bayanai da kowane mai amfani a cikin ɗakin ya samu. Tsarin ADR zai nuna ƙaramin rarrabuwa, mafi girma, yana nuna mafi daidaitaccen sabis da ingantaccen sabis ga masu amfani a wurare daban-daban (musamman kusa da bango ko a cikin kusurwoyi inda masu karɓa na Wide-FOV ke fama da hanyoyi da yawa).
  • Ginshiƙi 3: Mita Zaɓin Reshe: Taswira mai zafi a bene ɗakin yana nuna yawan sau da yawa kowane reshe na huɗu na ADR aka zaɓa a matsayin reshe mafi "kyau". Wannan zai nuna yanayin daidaitawa na ADR, tare da reshe daban-daban suna da kyau a yankunan ɗaki daban-daban.

8. Tsarin Bincike: Nazarin Lamari

Yanayi: Ƙirƙirar hanyar sadarwa ta VLC don buɗaɗɗen ofis tare da tashoshi aiki 20.

Aiwatar da Tsarin:

  1. Rarraba Matsala: Rarraba binciken kasafin hanyar haɗi zuwa: (a) Wutar Aikawa & Sauya Sauti, (b) Asarar Hanya ta Tashoshi & Amsar Motsa Jiki (ta amfani da bin haske), (c) Hankalin Mai Karɓa & Filin Gani.
  2. Ƙididdigar Fa'idar ADR: Ga kowane wurin tashar aiki, kwaikwayi ƙarfin siginar da aka karɓa da jinkirin yadawa ta amfani da mai karɓa na Wide-FOV da ADR mai reshe 4. Ƙididdige yuwuwar haɓakar SNR da raguwar ISI da ADR ke bayarwa ta hanyar ƙin hasashe masu zuwa a makare.
  3. Haɗa Masu Amfani NOMA: Tattara masu amfani zuwa nau'i-nau'i/ƙungiyoyin NOMA bisa bambance-bambancen ribar tasharsu, wanda yanzu ya fi bayyana kuma abin dogaro saboda tsaftataccen ƙididdigar tashar ADR.
  4. Simintin Tsarin Tsarin: Gudanar da simintin Monte Carlo yana canza ayyukan mai amfani da buƙatun bayanai. Kwatanta jimillar kayan aikin hanyar sadarwa da ƙimar mai amfani na kashi 5 (ma'aunin adalci) don tsarin ADR-NOMA vs. tsarin OFDMA-VLC na al'ada tare da masu karɓa na Wide-FOV.
Wannan tsarin yana ba mai ƙirar hanyar sadarwa damar kimanta ƙimar farashi-riba na tura ƙarin rikitaccen kayan aikin ADR da ribar ƙarfin da aka yi alkawari.

9. Ayyukan Gaba & Hanyoyin Bincike

  • 6G Li-Fi Backhaul/Downlink: ADR-NOMA VLC babban ɗan takara ne don saukar da saukarwa mai yawa a cikin hanyoyin sadarwa na 6G na gaba, yana haɓaka RF a cikin filin wasa, filayen jiragen sama, da masana'antu. Rashin amincewa da tsangwama na RF babban fa'ida ne.
  • Ultra-Reliable Industrial IoT: A cikin ma'ajiyar kaya ta atomatik ko layukan masana'antu, inda ƙananan jinkiri da aminci suke da mahimmanci, ADRs na iya samar da ingantattun hanyoyin haɗi don sadarwar inji-zuwa-inji, tare da NOMA yana tallafawa haɗin kai na firikwensin mai yawa.
  • Sadarwar Gani a Ƙarƙashin Ruwa: Yanayin tarwatsewa a ƙarƙashin ruwa yana kama da mummunan yanayi mai hanyoyi da yawa. ADRs na iya haɓaka kewayon da amincin sadarwar Laser shuɗi/kore don motocin ƙarƙashin ruwa masu cin gashin kansu.
  • Hanyoyin Bincike:
    • ADRs Masu Hankali: Amfani da tsarin micro-electromechanical systems (MEMS) ko tushen ruwa mai kristal don ci gaba, daidaitaccen daidaitawar kusurwa maimakon ƙafafun da aka gyara.
    • Ingantawar Layer Cross: Haɗin gwiwar inganta zaɓin ADR na Layer na zahiri tare da tsarin sarrafa matsakaici (MAC) da haɗin mai amfani na NOMA.
    • Tsarin RF/VLC na Hybrid: Bincika yadda ADR-NOMA VLC za a iya haɗa shi cikin sauƙi tare da mmWave ko ƙasa da 6 GHz RF a cikin hanyar sadarwa iri-iri, tare da ƙaddamar da zirga-zirga mai hankali.

10. Nassoshi

  1. Z. Ghassemlooy, W. Popoola, S. Rajbhandari, Sadarwar Wayar Mara Waya ta Gani: Tsarin da Ƙirar Tashoshi tare da MATLAB®, CRC Press, 2019. (Mai iko akan ƙirar tashar VLC)
  2. L. Yin, et al., "Non-orthogonal multiple access don sadarwar haske mai gani," IEEE Photonics Technology Letters, vol. 28, no. 1, 2016. (Takarda mai mahimmanci akan NOMA-VLC)
  3. J. M. Kahn, J. R. Barry, "Sadarwar infrared mara waya," Proceedings of the IEEE, vol. 85, no. 2, 1997. (Bita na tushe)
  4. T. Fath, H. Haas, "Kwatancen aikin dabarun MIMO don sadarwar wayar mara waya ta gani a cikin yanayin cikin gida," IEEE Transactions on Communications, vol. 61, no. 2, 2013. (Ya ƙunshi dabarun bambance-bambance)
  5. IEEE Standard for Local and Metropolitan Area Networks–Part 15.7: Short-Range Optical Wireless Communications, IEEE Std 802.15.7-2018. (Daidaitaccen da ya dace)
  6. M. O. I. Musa, et al., "Rarraba Albarkatu a Tsarin Sadarwar Haske Mai Gani," Journal of Lightwave Technology, 2022. (Aikin marubutan a baya, ref [36])
  7. PureLiFi. "Fasahar Li-Fi." https://purelifi.com/ (Shugaban masana'antu a cikin tallace-tallace na VLC)
  8. Z. Wang, et al., "Mai karɓar bambance-bambancen kusurwa don MIMO sadarwar haske mai gani," Optics Express, vol. 26, no. 10, 2018. (Nazarin aiwatar da ADR na musamman)