2018-07-18 19:28 GMT+08:00 Ben Whitten <Ben.Whitten@xxxxxxxxxxxxx>: >> Subject: Re: [RFC net-next 00/15] net: A socket API for LoRa >> >> + linux-wireless + Stefan + Seth >> >> Am 11.07.2018 um 17:21 schrieb Ben Whitten: >> >> This patchset is clearly not ready for merging, but is being >> >> submitted for >> >> discussion, as requested by Jiri, in particular of the design >> >> choices: >> >> >> >> 1) PF_LORA/AF_LORA and associated identifiers are >> >> proposed to represent >> >> this technology. While for an SX1276 - case a) above - it >> >> might work to >> >> layer LoRaWAN as a protocol option for PF_LORA and >> add >> >> LoRaWAN address >> >> fields to the union in my sockaddr_lora, how would that >> >> work for devices >> >> that only support LoRaWAN but not pure LoRa? Do we >> >> need both AF_LORA and >> >> AF_LORAWAN, or just a separate ETH_P_LORAWAN or >> >> ARPHRD_LORAWAN? >> >> >> >> 2) PF_LORA is used with SOCK_DGRAM here. The >> >> assumption is that RAW mode >> >> would be DGRAM plus preamble plus optional >> checksum. >> >> >> >> 3) Only the transmit path is partially implemented >> already. >> >> The assumption >> >> is that the devices should go into receive mode by >> default >> >> and only >> >> interrupt that when asked to transmit. >> >> >> >> 4) Some hardware settings need to be supplied >> externally, >> >> such as the radio >> >> frequency for some modules, but many others can be >> >> runtime-configured, >> >> such as Spreading Factor, Bandwidth, Sync Word, or >> which >> >> antenna to use. >> >> What settings should be implemented as socket option >> vs. >> >> netlink layer >> >> vs. ioctl vs. sysfs? What are the criteria to apply? >> >> >> >> 5) Many of the modules support multiple modes, such as >> >> LoRa, LoRaWAN and FSK. >> >> Lacking a LoRaWAN implementation, I am currently >> >> switching them into LoRa >> >> mode at probe time wherever possible. How do we >> deal >> >> with that properly? >> >> >> >> a) Is there any precedence from the Wifi world for >> >> dynamically selecting >> >> between our own trusted Open Source >> implementation >> >> vs. hardware/firmware >> >> accelerated and/or certified implementations? >> >> >> >> b) Would a proof of concept for FSK (non-LoRa) modes >> be >> >> required for >> >> merging any LoRa driver for chipsets that support >> both? >> >> Or is there any >> >> facility or design guidelines that would allow us to >> focus >> >> on LoRa and >> >> LoRaWAN and leave non-LoRa radio modes to later >> >> contributors? >> > >> > Down the line I think we should also plan for a CRDA style >> regdb somewhere in the path for raw LoRa transceivers >> operating as softMAC, much like with WiFi. >> >> Yes, I had raised the topic of wireless-regdb for Stefan's >> conference - >> currently it seems to only cover 2.4 GHz, 5 GHz and 60 GHz. >> Not sure if >> we can easily extend that to cover 433 MHz, 868 MHz, 915 >> MHz and 923 MHz >> bands or whether we'd just need something similar... Is >> 802.15.4 able to >> share this database with Wifi? > > Well the README in the wireless-regdb doesn't bind itself to 80211, there are references to the other ETSI EN specs so this would be the place rather than duplicating. > There would need a bit of additional information to capture duty-cycle requirements, however the SRD spec states the maximum bandwidths can be 'The whole band', so with a flag set we could hijack this band information for duty-cycle. > I am unsure if 802.15.4 uses this database, most of the naming seems geared towards 80211, nl80211, cfg80211 so perhaps we need our own versions of these with a common component, I hope the maintainers can give some guidance here. > >> An argument to share with Wifi might be that Semtech's >> SX1280 and SX1281 >> 2.4 GHz transceivers claim to support LoRa modulation, too. >> Having two >> different regulatory DBs interact with LoRa drivers seems a >> bad idea, >> and duplicating 2.4 GHz into a new DB doesn't sound >> appealing either. > > Well I'm not sure if the modulation affects regulatory information, just bands, power, and techniques like DFS. > As these chips are 2.4GHz only I expect they are bound by the existing regulatory information we would just need a path to access it. > >> https://www.semtech.com/products/wireless-rf/24-ghz- >> transceivers >> >> Meanwhile my attempt to play with netlink during SUSE >> Hackweek has been >> going slow and I could use some guidance or a volunteer to >> contribute: I >> have a bare skeleton of registration, commands, attributes >> and multicast >> groups, but no plan yet how to connect that to the actual >> drivers to >> query or apply the settings... > > Happy to help, I will be starting from zero on netlink but I can contribute my existing work incorporating Marks comments for sx1301 etal. > >> https://git.kernel.org/pub/scm/linux/kernel/git/afaerber/li >> nux-lora.git/tree/net/lora/netlink.c?h=lora-next Is this the repository used for the LoRa subsystem now?!!! If it is, than great! As the previous mails, I am trying to implement the LoRaWAN specification as the soft MAC as the MAC layer over LoRa PHY. This is the the talk about LoRaWAN class module I gave in Netdev Conf https://www.slideshare.net/chienhungpan/lorawan-class-module-and-subsystem The expectation is: socket APIs: send and receive the data ------------------------------------------------------------ LoRaWAN class module implements MAC: append the header/footer, encryption/decryption, timing slot and MAC commands ------------------------------------------------------------ LoRa device drivers: send and receive the messages for MAC layer ------------------------------------------------------------ LoRa devices Is it possible that combine the LoRaWAN class module I implemented? I start from the simplest class A end device's behavior, especially the timing slot. Also the encryption/decryption for uplink/downlink data messages. I can send it as patches. However, I have 2 problems right now. 1. Which Address and Protocol Family should we use? PF_LORA or PF_LORAWAN? 2. To test the LoRaWAN class module, adding more procedures in LoRa device drivers to register as a LoRaWAN device is needed. Regards, Jian-Hong Pan >> > LoRa radios used in Gateway devices are typically relatively >> high power (capable of 27dBm) and operate in bands with >> certain restrictions, eg the EU has keep out areas within >> 868MHz for alarms and SRD devices must abide by certain >> duty cycle restrictions, there are also maximum powers to >> consider for sub-bands. (ETSI EN 300 220-2 V3.2.1, Bands K, >> L, M, N, P, Q) >> >> > The certified AT style modules will (should) already have >> this regulatory data baked in so it only applied to situations >> where we drive the transceivers directly, but it wouldn't >> hurt to check that the frequency being asked to transmit on >> doesn't spill into a restricted band. >> >> Some do have configuration options that will need to be set >> or checked. >> >> Regards, >> Andreas >> >> -- >> SUSE Linux GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany >> GF: Felix Imendörffer, Jane Smithard, Graham Norton >> HRB 21284 (AG Nürnberg)
