On some networks that support the legacy SVLTE (Simultaneous Voice and
LTE) instead of the more modern VoLTE (Voice Over LTE) standard, or even
CSFB (Circuit-switched fallback) this number would (presumably) be even
LTE) or CSFB (Circuit-switched fallback) instead of the more modern VoLTE
(Voice Over LTE) standard, this number would (presumably) be even higher.
XMPP server and client implementers, bearing this increased power usage in
@ -153,12 +161,11 @@
@@ -153,12 +161,11 @@
traffic to minimize network usage.
For the downlink, LTE user equipment
(UE) utilizes Orthogonal Frequency Division Multiplexing (OFDM), which is
<note>A Close Examination of Performance and Power Characteristics of 4G LTE Networks <<linkurl='http://www.cs.columbia.edu/~lierranli/coms6998-7Spring2014/papers/rrclte_mobisys2012.pdf'>http://www.cs.columbia.edu/~lierranli/coms6998-7Spring2014/papers/rrclte_mobisys2012.pdf</link>></note>.
somewhat inefficient &huang12;.
On the uplink side a different technology, Single-carrier frequency
division multiple access (SC-FDMA) is used, which is slightly more
efficient than traditional (non linearly-precoded) OFDM, slightly
offsetting the fact that broadcasting requires more power than receiving.
efficient than traditional OFDM, slightly offsetting the fact that
broadcasting requires more power than receiving.
LTE UE also implements a Discontinuous reception (DRX) mode in which the
hardware can sleep until it is woken by a paging message or is needed to
perform some task.
@ -182,14 +189,14 @@
@@ -182,14 +189,14 @@
prevent the server from closing the socket.
<section2topic='Transmit as much data as you can at once'>
<section2topic='When transmitting, transmit as much as you can'>
If one is on 3G, transmitting a small amount of data will cause the
radio to enter FACH mode which is significantly cheaper than its high
On LTE radios, however, transmitting small amounts of data is vastly
more expensive per bit due to the higher tail-times (the time it takes
for the radio to change state).
more expensive per bit due to the higher tail-time (the time it takes
for the radio to change state) of approximately 11 seconds&huang12;.
On LTE radios, one should transmit as much data from the client as
possible when the radio is already on (eg. by placing messages in a send
queue and executing the queue as a batch when the radio is on).
@ -199,10 +206,8 @@
@@ -199,10 +206,8 @@
These rules also apply to server operators: If the server receives data,
the phones radio is already on therefore you should send any pending
Batching data to be sent and sending it all at once will help reduce
the phones radio is already on, therefore you should flush any pending
data as soon as possible after receiving data from a client.