OFDM is about as good as it gets with regards to multipath. Right now to reduce latency, I'm using the 4K carrier mode (3409 active carriers) which has a symbol duration of 448 microseconds (in 8 MHz bandwidth). That means a reflection from less than 134 km away will be in the same symbol.
DVB-T2 has six carrier modes. 1K, 2K, 4K, 8K, 16K and 32K. 1K is used for high Doppler applications (mobile) and 32K is used for high multipath. Almost all DVB-T2 television transmitters in Europe and Asia use the 16K or 32K mode. The BBC uses 32K for their multiplexes in the UK.
The new proposed US digital TV standard, ATSC 3.0, is almost identical to DVB-T2. It's basically DVB-T2 with some tweaks added to get another dB of S/N performance.
Ron W6RZ
On 09/02/2017 10:29 AM, Brian Kantor wrote:
Unless they've come up with a modulation scheme which overcomes the multipath distortion of transmitted symbols, I believe line of sight is practically a necessity.
But I'll be the first to admit that my communications theory knowledge is now many decades old. Perhaps there is a way around it.
- Brian