Hytera DMR System Planner
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30ms to 21ms!. Given this design goal, we have enhanced the slave repeaters IP
data transfer rate and has successfully increase the slave repeaters support from 16
in R3.0 to 22 in R3.5! Please note that the Hytera RND team is still optimizing the
slave amount and is continually researching to increase the slave amount to be
close to 30, promising more delighters to customer upcoming. Please stay tune for a
higher number of slave repeaters in upcoming release! (Given a single slot wide
area system operation, the amount of slave repeaters supported shall goes up to 44
slave repeaters, as compare to 22 repeaters in a dual slot wide area system
operation).
The UPD protocol, used for peer-to-peer service, is adopted for IP Multi-site
Connect feature at the transmission layer. It has no acknowledgements or
re-transmissions mechanism from the receiver to the sender. During transmission,
as the UDP data packet from the same node goes through different intermediate
nodes to reach different destination nodes, the packet jitter and disorder will occur.
In addition, the data packet may be lost when the network communication is poor.
The role of Jitter Buffer feature is to re-order the UDP data packet, buffer it and send
it later, which has no impact on signal. This is because the frame is sent or received
at a regular interval benefiting from the TDMA technology.
A UDP data packet is deemed to be lost if the time gap between it and last UDP data
packet arriving at the same node is over the threshold value. The buffer duration
shall be over this threshold. You can configure this duration according to the number
of jitter buffer.
The buffer duration ranges from 1*60 ms (default) to 8*60 ms.
You shall set the buffer duration according to the actual network transmission quality.
Shorter buffer duration means fewer packets to be buffered and less network delay
to be tolerated; on the contrary, more packets will be buffered and more network
delay will be tolerated, but this causes longer retransmission duration. Judging from
this, buffer duration increase is a double-edged sword. On the one hand, it improves
UDP data packet loss; on the other hand, it increases network transmission delay,
which may affect the digital services with acknowledgement required.
Currently, the network delay is measured by using Ping command. In a LAN or
private network where the network delay is generally less than 60ms, it is
recommended to use the default duration of jitter buffer. However, in other network
where the network delay is greater than 60ms, the duration is subject to actual
requirements.
When the IP Multi-site Connect feature is utilized in a WAN, the jitter buffer may not
help a lot due to bandwidth limitation and network resource preemption. Considering
this case, it is recommended to use the public network or establish your private
network for better communication.
Summary of Contents for PD70X Series
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Page 4: ...Revision History Version Date Description Remarks R1 0 November 21 2012 Initial release ...
Page 126: ...Hytera DMR System Planner 122 Figure 1 4 Analog to digital Conversion 2 ...
Page 174: ...Hytera DMR System Planner 170 For your notes ...
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