Oh, as an addendum, that whole dance that cellular does with inter-cell handover is known as "mobility management". There's also mobility management commands sent between base stations, or base stations and a control hub, which make the handover seamless and remove the requirement that the mobile station reauthenticate on each jump, like it must do with Wi-Fi - the mobile station will be provided all the parameters needed to instantly begin communication with the new cell via it's connection to the old cell before the jump is executed.
-- Kirn Gill II Mobile (SMS only): +1 813-300-2330 VoIP: +1 813-704-0420 Email: [email protected] LinkedIn: http://www.linkedin.com/pub/kirn-gill/32/49a/9a6 On Thu, Aug 1, 2019 at 7:42 PM Kirn Gill <[email protected]> wrote: > > Replying to Dave Taht, > > There's a few considerations here: > > - What is "5G"? > > Strictly speaking, 5G is ITU-T's IMT-2020 standard(s). So far, there > is only one system under this standard, 3GPP's New Radio (NR). NR is > what is meant as 5G in layspeak. > > The NR air interface is defined in 3GPP TS 38.xxx series documents. > > Against point 2, about operators simply wanting more active SIMs to > charge for, it's worth noting that NR can be deployed for private > operation; the company that's using the service could itself own the > entire network it's using. There are companies using private LTE > networks for V2x and remote sensing, see for example: > https://steelguru.com/mining/l/532247, or contract a third party to > build a dedicated network: > https://www.zdnet.com/article/telstra-deploys-private-lte-network-in-png-volcanic-crater-gold-mine/ > > NR operates over commercial and unlicensed frequency bands. The > specific frequency bands defined for the system are listed in 3GPP TS > 38.104 (Rel. 15) section 5.2 > > 802.11a/b/g/n/ac/ad use CSMA/CA - Carrier Sense Multiple Access with > Collison Avoidance - as their multiple access scheme, same as 802.3. > Each transmitter completely owns the medium when transmitting. > > 802.11ax, LTE, and NR use OFDMA - Orthogonal Frequency Division > Multiple Access - as their multiple access scheme. Instead of the > transmitter having the full channel for the duration it is > transmitting, OFDMA takes OFDM modulation and divides not only across > timeslots/timed transmission frames, but also by subdividing the full > channel into simpler "resource blocks" with a fixed number of OFDM > tones. > > LTE and NR have many features that Wi-Fi lacks which results in a far > superior user experience. OFDMA, only recently adopted for 802.11ax > ("Wi-Fi 6"), generally results in far superior throughput rates than > CSMA/CA when many users are involved. In LTE and NR, this is also > optimized further with centralized (at the eNB/gNB) MAC scheduling for > all traffic on both uplink and downlink. > > Inter-cell handover in all cellular systems is much better than in > Wi-Fi; Wi-Fi is a mobile-only system where the mobile station is in > full control of the process, and it's a "break before make", that is, > the mobile station fully disassociates from the first access point > before associating with the next access point, even in the case of a > shared BSSID and background Ethernet network. It's like unplugging > from one Ethernet port and plugging into another one rather quickly, > complete with the brief hiccup in network applications. > > Cellular is a lot better; the mobile station scans for neighboring > cells to the one it's connected to in it's spare time, and sends this > list to the network, so that the base station can "see" the different > signal strength's from the mobile station's perspective. The network > then instructs the mobile station to make a blind jump to whichever > cell it feels will best serve the mobile station and reduce power > consumption on that end. "Association" is with the network itself, not > with individual base stations, so there's no need to do the "break > before make" dance of Wi-Fi. > > -- > Kirn Gill II > Mobile (SMS only): +1 813-300-2330 > VoIP: +1 813-704-0420 > Email: [email protected] > LinkedIn: http://www.linkedin.com/pub/kirn-gill/32/49a/9a6 _______________________________________________ Bloat mailing list [email protected] https://lists.bufferbloat.net/listinfo/bloat
