Ntchito ya OpenWifi ndikukhazikitsa chipangizo chotseguka cha Wi-Fi kutengera FPGA ndi SDR

Pamsonkhano womaliza wa FOSDEM 2020 zoperekedwa kulemba openwifi, kupanga kukhazikitsa koyamba kotseguka kwa stack yathunthu ya Wi-Fi 802.11a/g/n, mawonekedwe azizindikiro ndi kusintha komwe kumatchulidwa mu pulogalamu (SDR, Software Defined Radio). OpenWifi imakulolani kuti mupange kukhazikitsidwa koyendetsedwa bwino kwa zigawo zonse za chipangizo chopanda zingwe, kuphatikiza zigawo zotsika, zomwe mu ma adapter opanda zingwe amayendetsedwa pamlingo wa tchipisi zomwe sizimawerengedwa. Kodi zigawo za mapulogalamundipo zithunzi ndi mafotokozedwe midadada ya hardware muchilankhulo cha Verilog cha FPGA imagawidwa pansi pa layisensi ya AGPLv3.

Chigawo cha Hardware cha chiwonetsero chowonetsedwa chogwira ntchito chimachokera pa Xilinx Zynq FPGA ndi AD9361 universal transceiver (RF). OpenWifi imagwiritsa ntchito zomangamanga za SoftMAC, zomwe zikutanthauza kukhazikitsidwa kwa stack yayikulu ya 802.11 (high-MAC) kumbali ya dalaivala ndi kukhalapo kwa gawo lotsika la MAC kumbali ya FPGA. Malo opanda zingwe amagwiritsa ntchito mac80211 subsystem yoperekedwa ndi Linux kernel. Kuyanjana ndi SDR kumachitika kudzera pa driver wapadera.

Zofunikira zazikulu:

• Thandizo lathunthu la 802.11a/g ndi kuthandizira pang'ono kwa 802.11n MCS 0~7 (PHY rx pokhapokha). Pali mapulani othandizira 802.11ax;
• Bandwidth 20MHz ndi ma frequency osiyanasiyana kuchokera ku 70 MHz mpaka 6 GHz;
• Njira zogwiritsira ntchito: Chisawawa (netiweki yazida zamakasitomala), malo ofikira, masiteshoni ndi kuwunika;
• Kukhazikitsidwa kwa protocol yolumikizira ulalo kumbali ya FPGA DCF (Distributed Coordination Function), pogwiritsa ntchito njira ya CSMA/CA. Amapereka chimango processing nthawi (Mtengo wa SIFS) pa mlingo 10us;
• Zosintha zoyambira zofikira panjira: nthawi ya RTS/CTS, CTS-to-self, SIFS, DIFS, xIFS, nthawi ya slot, ndi zina.
• Kuchepetsa nthawi (Kudula nthawi) kutengera adilesi ya MAC;
• Mafupipafupi osinthika komanso pafupipafupi:
  2MHz kwa 802.11ah ndi 10MHz kwa 802.11p;

Pakadali pano, OpenWifi imapereka thandizo FPGA-based SDR nsanja
Xilinx ZC706 yokhala ndi Zida za Analogi za FMCOMMS2/3/4 ma transceivers, komanso mitolo (FPGA + RF) ADRV9361Z7035 SOM + ADRV1CRR-BOB ndi ADRV9361Z7035 SOM + ADRV1CRR-FMC. Zapangidwa kuti zilowetse chithunzi chomaliza Makhadi a SD a ARM Linux. Pali mapulani othandizira ADRV9364Z7020 SOM + ADRV1CRR-BOB, Xilinx zed + FMCOMMS2/3/4, Xilinx ZCU102 + FMCOMMS2/3/4 ndi
Xilinx ZCU102 + ADRV9371. Mtengo wazinthu zomwe zidaphatikizidwa mu prototype yoyamba ya OpenWifi zinali pafupifupi ma euro 1300, koma kutengera matabwa otsika mtengo kukuchitika. Mwachitsanzo, mtengo wa yankho kutengera Zida za Analogi ADRV9364-Z7020 adzakhala 700 mayuro, ndipo pa maziko ZYNQ NH7020 - 400 euro.

Kuyesa kagwiridwe ka ntchito yolumikiza kasitomala ndi TL-WDN4200 N900 USB adaputala ku OpenWifi-based access point kunatipangitsa kuti tikwaniritse 30.6Mbps (TCP) ndi 38.8Mbps (UDP) posamutsa deta kuchokera pamalo olowera kupita kwa kasitomala ndi 17.0Mbps (TCP) ndi 21.5Mbps (UDP) pamene imatumizidwa kuchokera kwa kasitomala kupita kumalo olowera. Kwa oyang'anira, zida zokhazikika za Linux zitha kugwiritsidwa ntchito, monga ifconfig ndi iwconfig, komanso chida chapadera cha sdrctl, chomwe chimagwira ntchito kudzera pa netlink ndikukulolani kuti muwongolere magwiridwe antchito a SDR pamlingo wotsika (kusintha zolembetsa, kusintha magawo a nthawi, etc.).

Pakati pa mapulojekiti ena otseguka omwe akuyesa stack ya Wi-Fi, titha kuzindikira polojekitiyi WimeKupanga IEEE 802.11 a/g/p yogwirizana chopatsilira kutengera GNU Radio ndi PC yokhazikika. Mapulogalamu otsegula 802.11 opanda zingwe akupanganso ntchito Ziri и Sora (Microsoft Research Software Radio).

Source: opennet.ru