Image Processing Reference
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energy efficiency simultaneously to allow optimal network resource utilization. In
general, a service request should specify the traffic characteristics (e.g., source and
destination IP and port addresses, supported codecs, etc.), the desired QoS
(e.g., bandwidth, delay, jitter, packet loss and buffer), the energy requirement and
service personalization preferences. This session negotiation process may be han-
dled by using the OpenFlow protocol [
22
], the Session Initiation Protocol (SIP)
[
100
] or any other signaling protocol (e.g., Next Step In Signaling (NSIS) compliant
protocol [
97
]), specified by the network operator.
For the purpose of exposition, let us suppose that UE1 (previously attached to
eNB1) needs to perform handover to eNB2 through a cooperative link with UE2, as
in Fig.
8.10
. Hence, UE1 issues a service request to the SDNC. The service request
contains the context information about UE1 such as its QoS requirements (e.g., data
rate, delay, etc.), the traffic characteristics (e.g., codec), the remaining battery level,
the list of UE1
s available radio interfaces as well as the list of its neighbour UEs
(e.g., UE2). Based on the information received, the ARC evaluates the benefits to
the end-user and the impact on the overall network performance. Then, it decides to
grant or deny the handover request through UE2. More importantly in this
approach, the SDNC does not need to signal the communication paths to probe
resource availability since the CIR is populated with the information on real-time
manner. Also, in case the switching is granted, no QoS reservation release message
is needed along the previous path
'
. In addition, assuming that
the resource over-reservation solution described in [
23
] is deployed, as depicted by
Fig.
8.11
, no QoS resource reservation signaling message is required on the new
path
ER3, C1, C2, ER1
<
>
as long as the over-reserved resource is sufficient in the
requested CoS on the path. As such, it becomes clear that resource over-reservation
effectively allows for dynamic switching between QoS-enabled paths without
undue signaling overhead, thus contributing to the energy efficiency throughout
the network.
ER3, C1, C3, ER2
<
>
Fig. 8.11 An illustration of QoS over-reservation supporting cooperative communication
