User's Manual

AIR GIGARAY 70 GHz Technical Specification
Proprietary & Confidential Maribor, 25 June, 2020 Page 8 of 32
DOCSIS 3.1 specifications:
 OFDM modulation on downstream and upstream
 Downstream OFDM carriers are from 24MHz to 192MHz wide
 Upstream OFDMA carriers are from 20 to 96MHz wide
 OFDM uses individual narrowband sub-carriers
 Flexible modulation schemes: different modulation schemes based on cable modem
performance, Level of modulation is based on MER on CPE(customer unit)
 Improved error correction, LPDC, provide higher orders of modulation with the
same CNR
2.1.5. LATENCY
Delay in the DOCSIS network is created by transit time in the coax or wireless system. This
delay is actually very small adding 0.02 to 0.7 milliseconds to the total latency. The major
delay in DOCSIS networks is caused by queueing delay and media acquisition. Queuing
delay is caused by TCP acknowledgments in downstream and upstream data transmission.
This creates a large round-trip delay for data, which is also dependent on the latency of
both the downstream and upstream. Average latency in Globtel Gigaray system with or
without traffic is below 10 ms.