[opendtv] Re: 600 MHz Uplink and downlink blocks
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
- Date: Sun, 12 Mar 2017 00:45:29 +0000
Craig Birkmaier wrote:
Yes, with the cloud we are uploading more, but many of these services
are still very asymmetrical.
This article says that even though uplink requirements have been increasing,
asymmetrical service will continue to be the most cost-efficient even in the
future (although I note that FiOS advertises symmetrical these days, mostly as
a way to differentiate themselves, no doubt). Figure 2 is enlightening, showing
the ratio going from 2:1 to 4:1, at different times of day, where the greater
portion is downstream.
https://insight.nokia.com/symmetrical-bandwidth-myth-or-must
One interesting point made is that while services like voice telephone or video
conferencing would be symmetrical in principle, any kind of multi-party voice
or videoconferencing ends up making this service asymmetrical too.
As to same bandwidth for uplink and downlink, the uplink is more handicapped
than downlink. Low power devices, which need to conserve battery life, and with
very small antennas. So uplink tends to be less spectrally efficient than
downlink, to compensate. So you need to expect asymmetry in bit rate capacity,
even if the bands are equal width.
http://www.radio-electronics.com/info/cellulartelecomms/lte-long-term-evolution/3gpp-4g-imt-lte-advanced-tutorial.php
Check out the spectral efficiencies. They are 2:1 in favor of downlink, for
LTE-A.
Bert
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