Bincike na Sabon Lambar RLL 5B10B don Ingantacciyar Sadarwar Haske Mai Gani

1. Gabatarwa & Bayyani

Sadarwar Haske Mai Gani (VLC) tana amfani da kayayyakin hasken LED don watsa bayanai, tana gabatar da ƙalubale na musamman kamar rage lumshe ido da sarrafa haske. Ma'auni na IEEE 802.15.7 ya tilasta amfani da lambobin Run-Length Limited (RLL) kamar Manchester, 4B6B, da 8B10B don tabbatar da daidaiton DC, hana lahani na haske. Duk da haka, waɗannan lambobin gargajiya ba su da iyakataccen gyaran kuskure na asali, galibi suna buƙatar ƙarin matakan lambobin tashoshi waɗanda ke rage ingantacciyar ƙimar bayanai. Wannan takarda ta gabatar da sabuwar lambar RLL 5B10B da aka ƙera don cike wannan gibi, tana ba da ƙarfin gyaran kuskure yayin kiyaye mahimman daidaiton DC da ƙarancin sarƙaƙƙiya da ake buƙata don tsarin VLC na zahiri.

2. Tsarin Lambar 5B10B da Aka Gabatar

Babban ƙirƙira yana cikin sabon tsarin canzawa daga 5-bit zuwa 10-bit (5B10B). Wannan yana kiyaye ƙimar lambar $R = \frac{5}{10} = 0.5$, daidai da lambar Manchester, yana tabbatar da dacewa da tsammanin ma'auni don faɗaɗa bandwidth a cikin tsare-tsaren RLL.

2.1. Tsarin Lamba & Tsarin Canzawa

An ayyana lambar ta hanyar teburin nema (wanda aka nuna daga rubutun) wanda ke canza kowane 5-bit na yuwuwar kalmomin bayanai 32 zuwa takamaiman kalmar lamba ta 10-bit. An ƙera tsarin canzawa a hankali don cimma manufofi da yawa lokaci guda: iyakance madaidaicin bit ɗaya (tsawon gudu), kiyaye jimlar dijital mai kusan sifili (daidaiton DC), da haɓaka nisan Hamming tsakanin kalmomin lamba don gano/gyaɗa kuskure.

2.2. Daidaiton DC & Sarrafa Tsawon Gudu

Matsakaicin daidaiton DC yana da mahimmanci ga VLC don guje wa sauye-sauyen haske na ƙananan mitoci waɗanda ke haifar da lumshe ido, wanda ma'auni ke tsarawa ta hanyar ayyana Mafi Girman Lokacin Lumshe Idan (MFTP). An gina kalmomin lambar 5B10B da aka gabatar don rage ƙimar jimlar dijital, yana magance wannan ƙuntatawa na matakin kayan aiki kai tsaye fiye da wasu shawarwari na baya kamar Lambobin Ƙimar Haɗin Kai (URC) waɗanda suka sassauta daidaiton DC don mafi girman ƙima.

3. Binciken Fasaha & Aiki

3.1. Tsarin Gyaran Kuskure

Ingantaccen aikin kuskure ya samo asali ne daga ƙaramin nisan Hamming ($d_{min}$) da aka ƙera na lambar. Yayin da lambobin RLL na gargajiya kamar Manchester suna da $d_{min}=2$ (ba su ba da izinin gano kuskure kawai ba), tsarin canzawa na lambar 5B10B yana ƙara wannan nisa. Mafi girman $d_{min}$ yana ba da damar mai ɗaukar lamba ya gyara takamaiman adadin kurakurai na bit ($t$) a kowace kalmar lamba, inda $t = \lfloor (d_{min} - 1)/2 \rfloor$. Wannan ƙarfin gyara na asali yana rage Ƙimar Kuskuren Bit (BER) a mai karɓa ba tare da ƙara matakin mai ɗaukar lamba na FEC daban ba.

3.2. Binciken Ka'idar BER

Don siginar da aka daidaita ta OOK akan tashar AWGN, ka'idar BER don tsarin da ba a yi masa lamba ba ana bayar da ita ta $P_b = Q\left(\sqrt{\frac{2E_b}{N_0}}\right)$, inda $Q(\cdot)$ shine aikin Q. Tsarin da aka yi masa lamba tare da ƙimar lamba $R$ da ƙaramin nisa $d_{min}$ na iya cimma kusan iyaka sama akan BER: $P_b \lessapprox \frac{1}{2} \text{erfc}\left(\sqrt{R \cdot d_{min} \cdot \frac{E_b}{N_0}}\right)$. Lambar da aka gabatar tana inganta hujja a cikin aikin $Q$ ta hanyar $R \cdot d_{min}$ idan aka kwatanta da tsarin da ba a yi masa lamba ba, yana bayyana mafi kyawun aikin sa a cikin tsarin SNR mai matsakaici zuwa babba.

4. Sakamakon Siminti & Kwatanta

4.1. Aikin BER vs. Lambobin Ma'auni

Takardar ta gabatar da sakamakon siminti wanda ke kwatanta lambar 5B10B da lambobin ma'auni na IEEE 802.15.7 (misali, Manchester, 4B6B) a ƙarƙashin daidaitawar OOK. Babban binciken shine rage BER mai mahimmanci don lambar 5B10B a daidai ƙimar Sigina-zuwa-Huru (SNR). Misali, don cimma manufar BER na $10^{-5}$, lambar 5B10B na iya buƙatar ƙasa da 1-2 dB na SNR fiye da lambar Manchester. An danganta wannan ribar kai tsaye ga kaddarorin gyaran kuskurenta. Aikin ya zarce na tsarin haɗaɗɗu (misali, RS + 4B6B) a ƙarancin sarƙaƙƙiya, saboda yana guje wa jinkiri da ƙarin aiki na mai ɗaukar lamba na FEC daban.

4.2. Kimanta Sarƙaƙƙiya

Babban fa'ida shine kiyaye ƙarancin sarƙaƙƙiya. Ana iya aiwatar da ɓoyewa da ɗaukar lamba ta hanyar sauƙaƙan teburin nema (ROM) ko dabaru na haɗawa, kama da lambobin gargajiya na 4B6B/8B10B. Wannan ya bambanta da ƙarin tsare-tsare masu sarƙaƙƙiya na ɗaukar lamba mai laushi don lambobin haɗaɗɗu [3,5] ko ɗaukar lamba na tushen trellis na lambobin eMiller [8], yana sa lambar 5B10B ta dace sosai don masu watsawa da karɓa na VLC masu ƙarancin albarkatu, masu sauri.

5. Fahimtar Jigo & Ra'ayin Mai Bincike

Fahimtar Jigo: Lambar 5B10B ta Reguera ba kawai ƙaramin gyara ba ce; juyawa ce mai dabara daga ɗaukar RLL a matsayin "mai siffa na bakan gizo" kawai zuwa gane shi a matsayin babban matakin lambar tashoshi. Haƙiƙanin ci gaba shine yarda cewa a cikin hanyoyin haɗin VLC masu ƙarfi da jinkiri (tunanin Li-Fi don IoT ko sadarwar abin hawa-zuwa-abin hawa), ƙarin aiki na FEC mai ƙarfi daban kamar lambobin LDPC ko Polar na iya zama mai hana. Wannan aikin yayi wayo yana saka isasshen redundancy a cikin tsarin RLL kanta don yaƙi da manyan tsarin kuskure a cikin VLC na tushen OOK na yau da kullun, yana ƙirƙirar FEC "mai kyau isa" don yawancin yanayi na zahiri. Yana bin yanayin da aka gani a wasu ƙuntatattun tashoshi, kamar ingantacciyar lamba don ƙwaƙwalwar ajiya mai walƙiya, inda ƙirar lamba ke da alaƙa da cikakkun bayanai na matakin zahiri.

Kwararar Hankali: Hujjar tana da sauƙi mai ban sha'awa: 1) VLC tana buƙatar lambobin daidaitattun DC (RLL). 2) Ma'auni suna amfani da RLL amma sai suna buƙatar ƙarin FEC, suna cutar da ƙima/sarƙaƙƙiya. 3) Fasahar da ta gabata ko dai ta ƙara sarƙaƙƙiyar ɗaukar lamba [3,5,9] ko ta yi sulhu da daidaiton DC [6,7]. 4) Saboda haka, ƙirƙiri sabuwar lambar RLL daga tushe tare da kaddarorin FEC. Hankali yana da kyau, amma babban mayar da hankali na takardar akan OOK da matsakaici-babban SNR shine yarda a ɓoye na ƙwarewarta: ba lamba ta duniya ba ce amma ingantaccen mafita ne don takamaiman yanki na aiki mai mahimmanci.

Ƙarfi & Aibobi: Ƙarfin kyawun salo da amfani ba shakka. Aiwatar da teburin nema mafarki ne ga masu ƙira FPGA/ASIC. Duk da haka, aibin yana cikin iyakacin iyaka. Ta yaya yake fuskantar ƙarƙashin ISI mai tsanani daga hanyoyi da yawa a cikin VLC na cikin gida? Takardar ba ta yi magana game da aiki tare da daidaitawa mafi girma (kamar VPPM kuma a cikin 802.15.7) ba, waɗanda ke da mahimmanci don tallafin duhu. Bugu da ƙari, "ingantaccen gyaran kuskure" yana da alaƙa; don ƙananan SNR sosai, za a buƙaci ƙwararren FEC na musamman. Lambar gada ce, ba maye gurbin ba, don ingantaccen lambar tashoshi a cikin yanayi masu ƙalubale.

Fahimta Mai Aiki: Ga masu ƙira tsarin: nan da nan ku kimanta wannan lambar 5B10B don kowane sabon ƙirar samfurin VLC na tushen OOK, musamman inda farashi da wutar lantarki suke da mahimmanci. Zai iya rage adadin abubuwan haɗin gwiwa. Ga masu bincike: Wannan yana buɗe madaidaicin jijiya. Za a iya ƙaddamar da wannan ƙa'idar zuwa lambobin 6B12B ko 8B16B don bambancin ciniki na ƙima/aiki? Za a iya amfani da ilmantarwa mai zurfi don inganta teburin tsarin canzawa na kalmar lamba don takamaiman samfuran tashoshi, kamar yadda ake amfani da hanyoyin sadarwar jijiya don ƙirƙirar lambobi don takamaiman tashoshi? Ga ƙungiyoyin ma'auni (IEEE, ITU): Lokaci ya yi da za a sake ziyartar kayan aikin matakin zahiri na VLC. Yakamata a yi la'akari da lambobi kamar 5B10B a matsayin lambobi na zaɓi ko shawararri a cikin gyare-gyaren gaba na 802.15.7 ko a cikin sabbin ma'auni kamar waɗanda ake tattaunawa akan Li-Fi (IEEE 802.11bb). Ya kamata a ƙalubalanci zamanin ɗaukar lambar layi da lambar tashoshi a matsayin matsaloli daban-daban, masu bi da bi a cikin VLC.

6. Cikakkun Bayanai na Fasaha & Tsarin Lissafi

Ana iya bincika aikin lambar ta hanyar mai ƙidaya nauyi ko bakan nisa. Bari $A_d$ ya zama adadin kalmomin lamba tare da nauyin Hamming $d$. Haɗin haɗin haɗari akan yuwuwar kuskuren kalmar lamba don lambar layi ta binary akan tashar AWGN tare da BPSK/OOK shine: $$P_e \leq \sum_{d=d_{min}}^{n} A_d \, Q\left(\sqrt{\frac{2d R E_b}{N_0}}\right)$$ inda $n=10$ shine tsawon kalmar lamba. Babban manufar ƙira ita ce haɓaka $d_{min}$ da rage ƙididdiga $A_d$ don ƙananan kalmomin lamba, ta haka ne a ƙara matse wannan iyaka. Ƙuntatawar daidaiton DC tana ƙara wani mataki zuwa ingantawa, galibi ana tsara shi azaman rage mafi girman ƙimar mutumta na Jimlar Dijital Gudu (RDS): $\text{RDS} = \sum_{i=1}^{k} (2c_i - 1)$, inda $c_i$ su ne bit ɗin da aka yi masa lamba zuwa ±1. Lambar da aka gabatar mai yiwuwa tana kiyaye $|\text{RDS}| \leq S_{max}$ don ƙaramin $S_{max}$ akan kowace kalmar lamba ko ɗan gajeren jerin kalmomin lamba.

7. Tsarin Bincike & Misalin Ra'ayi

Tsari: Kimanta sabuwar lambar layin VLC ya ƙunshi sararin ciniki mai girma mai girma: 1) Bakan & Daidaiton DC (RDS, PSD), 2) Aikin Kuskure ($d_{min}$, BER vs. SNR), 3) Sarƙaƙƙiyar Aiwatarwa (ƙidaya ƙofa, girman ƙwaƙwalwar ajiya), 4) Haɗin Tsarin (dacewa tare da duhu, daidaitawa).

Nazarin Hali na Ra'ayi - Tsarin Matsayin Cikin Gida: Yi la'akari da tsarin matsaya na cikin gida na tushen VLC inda LEDs ke watsa ID da bayanan wurinsu. Tashar tana da hayaniya matsakaici (SNR ~12-15 dB), kuma ƙaramin jinkiri yana da mahimmanci don bin diddigin ainihin lokaci. Yin amfani da daidaitaccen lambar Manchester zai iyakance kewayo ko kuma ya buƙaci mai ɗaukar lamba na FEC daban, yana ƙara wutar lantarki da jinkiri. Aiwatar da lambar 5B10B yana ba da damar irin wannan kayan aikin tuƙi na LED su watsa tare da ƙananan BER ɗin ɗanyen. Wannan kai tsaye yana fassara zuwa ko dai faɗaɗa yankin ɗaukar hoto don irin wutar LED ɗaya, ƙara ƙimar sabunta matsayi, ko mafi ingantacciyar amincin gyaran wuri, duk ba tare da canza ainihin daidaitawa (OOK) ko ƙara guntuwar ɗaukar lamba masu sarƙaƙƙiya ba. Wannan yana nuna ƙimar lambar a cikin aikace-aikacen VLC masu ƙarancin ƙididdigewa, ƙarancin wutar lantarki.

8. Ayyukan Gaba & Hanyoyin Bincike

Lambar 5B10B tana buɗe hanyar don aikace-aikace da yawa na ci gaba da zaren bincike:

• Bayyan OOK: Bincika aikin lambar tare da VPPM da Daidaitawar Girman bugun jini (PAM) don sadarwa lokaci guda da sarrafa duhu daidai.
• Lambobi Masu Inganta Kayan Koyon Injina: Yin amfani da ilmantarwa mai ƙarfafawa ko algorithms na kwayoyin halitta don bincika babban sararin tsarin canzawa na 5B10B don mafi kyawun bakan nisa a ƙarƙashin ƙuntatawa da yawa (RDS, lumshe ido, bene na kuskure).
• Haɗawa tare da Ingantaccen FEC: Yin amfani da lambar 5B10B a matsayin lamba ta ciki a cikin tsarin haɗaɗɗu tare da lambar waje ta zamani kamar lambar Polar mai ƙarancin ƙima (kamar a cikin 5G) ko lambar LDPC mai haɗaɗɗiyar sarari. Lambar 5B10B za ta ɗauki lumshe ido kuma ta ba da matakin gyara na farko, yana sauƙaƙe aikin ga lambar waje.
• Daidaituwa a cikin Sabbin Fannonin VLC: Haɓaka lambar don amfani a cikin VLC na ƙarƙashin ruwa (UWVLC), inda yanayin tashoshi yake da tsauri kuma ingantaccen wutar lantarki yana da mahimmanci, ko a cikin sadarwar kyamara ta gani (OCC) don wayoyin hannu.
• Masu Nuna Kayan Aiki: Haɓaka aiwatarwar FPGA ko ASIC na buɗe tushe don gwada ainihin amfani da wutar lantarki da kayan aiki da 4B6B da 8B10B cores.

9. Nassoshi

1. Ma'auni na IEEE don Gida da Manyan Hanyoyin Sadarwa--Sashi na 15.7: Sadarwar Gajeren Zango ta Optical ta Amfani da Haske Mai Gani, IEEE Std 802.15.7-2018.
2. Komine, T., & Nakagawa, M. (2004). Bincike na asali don tsarin sadarwar haske mai gani ta amfani da hasken LED. IEEE Transactions on Consumer Electronics.
3. Griffin, R. A., & Carter, A. C. (2002). Watsa lambar Manchester ta gani ta amfani da mai haɓaka na'urar gani ta semiconductor. Electronics Letters.
4. Lee, K., & Park, H. (2011). Sabuwar lambar RLL don sadarwar haske mai gani tare da gyaran kuskure na asali. Proc. ICTC. (Magabacin ra'ayi ga haɗin gwiwar FEC-RLL).
5. Wang, Q., et al. (2020). Koyon Zurfi don Lambar Tashoshi: Cikakken Bincike. IEEE Communications Surveys & Tutorials. (Mahallin akan ƙirar lamba ta tushen ML).
6. 3GPP TS 38.212. (2020). NR; Haɗawa da lambar tashoshi. (Don nassoshi akan lambobin Polar da aka yi amfani da su a cikin rediyo na ci gaba).
7. Reguera, V. A., et al. (2022). A kan Rage Lumshe Idan a cikin Sadarwar Haske Mai Gani tare da Lambobin Ƙimar Haɗin Kai. IEEE Photonics Journal. (Aikin da ya gabata na marubucin da aka ambata a cikin PDF).