Ukuqala nge-RFID

Isistimu ye-UHF RFID inezingxenye ezintathu: umfundi, izimpondo eziningi, namathegi. Umfundi ukhiqiza isignali yomsakazo engu-920–925 MHz futhi uyithumele ngempondo. Lapho ithegi engasebenzi ingena emkhakheni wempondo, ithatha amandla evela emhlabeni womsakazo ukuze inike amandla i-microchip yayo encane (ngokuvamile idinga nje ~10 microwatts). I-chip bese iguqula isignali engenayo bese iyibuyisela emuva. ngempela ibonisa inguqulo eguquliwe emuva. Lesi siginali esibuyisiwe sithwala i-Electronic Product Code (EPC) eyingqayizivele yethegi.

Umjikelezo wonke wokufunda. kusukela ekudluliseni umbuzo kuya ekwamukeleni impendulo yethegi. kuthatha cishe imilisegondi engu-1–3. Yilokhu okwenza umfundi oyedwa akwazi ukuthatha uhlu lwamathikithi angaphezu kwama-200 ngomzuzwana ngamunye esebenzisa iphrothokholi yokulwa nokuqhumisa ye-EPC Gen2. Ukulahleka kwesiginali yohambo oluyindilinga kubalulekile (-40 kuya ku-80 dB), yingakho amandla omfundi we-TX (ngokuvamile 30 dBm / 1 watt) kanye nokuzwela kwe-chip yethegi (kufika ku-22 dBm) kuyizincazelo ezibaluleke kakhulu.

I-RFID ihlanganisa amabhendi amaningi wemvamisa, kodwa i-UHF (860–960 MHz) ibusa izinhlelo zokusebenza zezentengiso ngoba inikeza ibhalansi engcono kakhulu yebanga lokufunda, isivinini, kanye nezindleko zethegi. I-LF (125 kHz) ifunda ngaphakathi kuka-10cm ku-~1 thegi/sec. ilungele ukulandelela izilwane kodwa ihamba kancane kakhulu ngemisebenzi yezokuthutha. I-HF/NFC (13.56 MHz) ifinyelela ku-~1m ku-~50 amathegi/sec. ilungele izinkokhelo namakhadi okufinyelela. I-UHF ifinyelela ku-1–12+ amamitha ku-200+ amathegi/sec. ilungele ukuhlinzekwa kwezinto, ukuthengisa, nokulandelela impahla.

Ngaphakathi kwebhendi le-Vietnam 920–925 MHz, abafundi basebenzisa i-Frequency Hopping Spread Spectrum (FHSS) ezinqamula iziteshi eziningi. Ifomula ithi: imvamisa = 920.0 + (isiteshi_index × 0.5) MHz. Ukucushwa okujwayelekile kusebenzisa iziteshi ezi-6 [0, 2, 4, 6, 8, 10] ezihlanganisa u-920.0 kuya ku-925.0 MHz ukuze kutholwe ukuhlukaniswa kwesiteshi esiphezulu.

Channel Index → Frequency (MHz)   Formula: f = 920.0 + (idx × 0.5)

Ch 0  → 920.0    Ch 4  → 922.0    Ch 8  → 924.0
Ch 1  → 920.5    Ch 5  → 922.5    Ch 9  → 924.5
Ch 2  → 921.0    Ch 6  → 923.0    Ch 10 → 925.0
Ch 3  → 921.5    Ch 7  → 923.5

Typical: use [0, 2, 4, 6, 8, 10] for max channel separation

Ithegi ngayinye ye-UHF RFID inezingxenye ezimbili ezibalulekile: iphethini le-antenna (i-aluminium eqoshwe noma eprintiwe ku-substrate ye-PET) kanye ne-microchip (IC). I-antenna ithatha isignali yomfundi futhi i-chip icubungula imiyalo futhi ibuyisele idatha. Ukuzwela kwe-chip ngamandla amancane i-chip ewadingayo ukuze isebenze. i-chip elinganiswe ku--22.1 dBm ingavuka ngama-microwatts angu-~6.3 nje. Okuncane (okubi kakhulu) = ukuzwela okungcono = ibanga lokufunda elide.

Imindeni ye-chip ejwayelekile ihlanganisa: i-NXP UCODE 9 (-22.1 dBm, 128-bit EPC, akukho nkumbulo yomsebenzisi. ibusa ekuthengiseni), uchungechunge lwe-Impinj M700 (-22.1 dBm, 128-bit EPC. iqinile emisebenzini yezokuthutha), kanye ne-Quanray QStar-7U (-21.0 dBm, 128-bit EPC, 512-bit inkumbulo yomsebenzisi. ilungele uma udinga ukugcina idatha ngokuqondile kuthegi).

Izici zefomu lethegi: Ama-Inlays Omile (ithegi eluhlaza ku-PET, ¢3–8, yokuguqula kube amalebula), Ama-Inlays Amanzi (anokunamathisela, ¢5–12, alungele ukusetshenziswa), Amalebula Esitikha (aphintwayo, ¢8–25, anegama lomkhiqizo), Amathegi Aqinile ($1–15, aqinisiwe ezindaweni ezinzima), kanye namalebula alukiwe/endwangu (¢15–40, athungwe ezingutsheni). I-Nextwaves ikhiqiza ama-inlays omile kusuka ku-35×17mm kuya ku-95×8mm kanye namalebula esitikha ngosayizi ofanayo.

I-EPCglobal Gen2 (ISO 18000-6C) ilawula ukuthi abafundi be-UHF baxhumana kanjani namathegi. Okusha okubalulekile yi-algorithm ye-slotted-ALOHA anti-collision evumela umfundi oyedwa ukuthi ahlolisise amakhulu amathegi ngasikhathi sinye ngaphandle kokuthi aphazamise omunye nomunye.

Nansi indlela umjikelezo wokuhlola osebenza ngayo: Umfundi uthumela i-Query enepharamitha ethi Q (idala izikhala zesikhathi ezingu-2^Q). Ithegi ngayinye ikhetha isikhala esingahleliwe bese ilinda. Lapho isikhala sethegi sifika, siphendula ngenombolo engahleliwe engu-16-bit. Uma ithegi eyodwa kuphela ephendulayo, umfundi uyavuma futhi wamukela i-EPC egcwele. Uma amathegi amaningi eshayisana, umfundi weqa leso sikhala. Ngemuva kwazo zonke izikhala, i-Q ilungiswa. phezulu uma kushayisana okuningi kakhulu, phansi uma izikhala eziningi kakhulu ezingenamuntu. futhi umjikelezo uyaphinda.

Izilungiselelo eziphathekayo ze-Q: Q=2 (izikhala ezi-4) zamathegi angu-1–5, Q=4 (izikhala ezingu-16) zamathegi angu-5–20, Q=5 (izikhala ezingu-32) zamathegi angu-20–100, Q=6 (izikhala ezingu-64) zamathegi angu-100–500, Q=7 (izikhala ezingu-128) zamathegi angu-500+. I-Q ephezulu isho ukushayisana okuncane kodwa imijikelezo ehamba kancane.

Ukugcinwa kweseshini kulawula ukuthi ithegi ilikhumbula isikhathi esingakanani ukuthi isifundiwe. Iseshini S0 isetha kabusha ngokushesha (ukuqapha okuqhubekayo). I-S1 ihlala imizuzwana engu-0.5–5 (ukuhlola okujwayelekile). I-S2/S3 ihlala ≥2 imizuzwana (iminyango yezindawo zokubeka impahla nezithuthi lapho ufuna ukuthi ithegi ngayinye ibalwe kanye ngokuphasa ngakunye). Umthetho wesithupha: sebenzisa i-S0 ekuqapheni ishelfu, i-S2/S3 ezingosini.

Tag Count → Q Value → Slots → Use Case

  1-5       Q=2       4       fast, low overhead
  5-20      Q=4       16      good balance
  20-100    Q=5       32      warehouse shelves
  100-500   Q=6       64      pallet scanning
  500+      Q=7       128     dock doors, bulk

Higher Q = fewer collisions but slower rounds

Ithegi ngayinye ye-Gen2 inamabhange ememori ama-4. I-Reserved (Ibhange 00): Iphasiwedi yokubulala + Iphasiwedi yokufinyelela, ama-bits angu-64 esewonke. I-EPC (Ibhange 01): I-CRC-16 + Izwi Lokulawula Iphrothokholi + isihlonzi sakho se-EPC, ngokuvamile ama-bits angu-96–128. I-TID (Ibhange 10): I-ID ye-chip eyingqayizivele eshisiwe efekthri engasoze yashintshwa. okungenani ekulweni nokuqanjwa kwamanga. Umsebenzisi (Ibhange 11): Ukugcinwa kwedatha okwenziwe ngokwezifiso (0 kuya kuma-bits angu-512+ kuye nge-chip), okuwusizo ezinombolweni zeqoqo, izinsuku zokuhlola, noma idatha yenzwa.

Lapho umfundi ethatha uhlu lwamathikithi, isaziso ngasinye siqukethe: i-ID yempondo (yimuphi imbobo), inani eliluhlaza le-RSSI (0–255, guqula libe yi-dBm nge: dBm = -100 + round(raw × 70 / 255)), idatha ye-EPC (ama-byte angu-12+), kanye nenkomba yesiteshi semvamisa. Le datha yilokho uhlelo lwakho lokusebenza olulucubungulayo ukuze lihlanganise ukufundwa kwethegi ngokomzimba ezenzakalweni zebhizinisi ezifana 'nento ethunyelwe' noma 'ipalethi etholiwe'.

[ANT] [RSSI] [EPC ×12 bytes ..................] [CH]
 01    B4     30 34 25 7B F7 19 4E 40 00 00 1A 85  06

Antenna:  1 (port 1)
RSSI:     180 → dBm = -100 + round((180×70)/255) = -51 dBm
EPC:      3034257BF7194E4000001A85 (SGTIN-96)
Channel:  6 → 920.0 + (6×0.5) = 923.0 MHz
GTIN-14:  80614141123458  Serial: 6789

Nasi uhlu lokuhlola olusebenzayo lokusetha uhlelo lwakho lokuqala lwe-RFID, olunokuqondisa okuthile esinyathelweni ngasinye.

Input:  GTIN-14=08600000232451  Serial=1001  Prefix=7 digits
Output: 30 14 1A 80 0E 98 78 00 00 00 03 E9  (12 bytes)