HANDOVER SCHEME FOR C/U-PLANE SPLIT HETEROGENEOUS NETWORKS IN HIGH-SPEED RAILWAY
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$250-750 USD
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Currently, many countries are constructing their high-speed railway system
to offer high speed transportation system for passengers those are traveling for long
distance. since passengers may stay in train for long period of time, it will be
attractive to provides them with data services. However, it is challenging task because
all Users Equipment (UE) devices in train have to perform handover frequently at
the same times. This will leads to incur network loads and degraded the network
performance quality. In general when the UE communicate directly with the Evolved
NodeB (eNodeB) it will suffer from a severe degradation of the quality of service
due to path loss and shadowing effect as the wireless signal travailing across the train
carriage. To cope with this issues, the Third-Generation Partnership project (3GPP)
has supported relay communications in the Long-Term Evolution advanced (LTE-A)
release 10 standard [7, 8, 9]. Indeed, using Mobile Relays (MRs) within the highspeed
railway enhances the cellular coverage and overcome the moderate to high
vehicle penetration loss (VPL)[10, 11] and also help to group handover procedures
of (UE) devices, mobile relay also suffer from frequent handover. For example assume
the train travailing with speed of 350 km/h, and going across a coverage area of a
cell size of 2 km, thus the mobile relay will encounter handover every 20.6 s. It is
obvious that the mobile relay will be served by the eNodeB for a very short time.
Moreover, according to the specification of LTE-A [12, 13], the MR has to perform
a measurement procedure before the handover procedure to insure that the signal
quality from the target eNodeB is better than the serving eNodeB. The serving eNodeB
made a handover decision based on the measurement results from the mobile relay
MR. when the serving eNodeB decides that the MR has to handover to the target
eNodeB, the core network then starts the in network handover procedure. However
the current specifications shows that the measurement procedure may take a longer
time period and thus, delays the handover trigger timing. In LTE-A, the measurement
procedure and in network handover procedure are mainly designed for UEs with low to
medium velocities and not suitable for high-speed railway (HSR). Thus, this research
are mainly focused in adopting a mobile relay (MR) between the UE and the eNodeB
in Control/User-Plane(C/U-plane) split heterogeneous networks architecture for high speed
railway. then propose a suitable handover parameters measurement procedure
and in network handover procedure for the high-speed railway in control/user (C/U)
plane split heterogeneous networks to enhance the handover delay of the overall
handover procedure .