Your Cellphone Will Be a Satphone

Re:Your Cellphone Will Be a Satphone by snovv_crash on Wednesday December 28, 2022 @05:13AM (#34159408)

I didn't realise that 4G/5G could connect to receivers that far away. From memory, the maximum Timing Advance in 2G corresponded to ~25km. After that the phones won't get ACKs fast enough due to speed of light and will assume that the response isn't for them.

WiFi has similar limits, but much shorter. I know some usecases of WiFi transceivers with longer distances (~5km) which required tweaked firmware that wasn't technically wifi-compliant, to have longer receive windows.

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Re:Your Cellphone Will Be a Satphone by shenberg on Wednesday December 28, 2022 @07:25AM (#34160326)

Even in 2G you have special cells that allocate two+ adjacent time-slots for a channel and so can effectively double the max range at the cost of serving less concurrent clients. This is used in sparsely populated regions (think remote highways etc). It's not a physical, the-signal-can't-reach issue.

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