1 Introduction
2 Related works
3 Proposed PIHM framework
4 Characterization of channel availability in CR-MANETs
Symbol | Meaning |
---|---|
R
T
| Node transmission range |
C
| Total number of available channels |
c
| Number of possible channels at each node |
l
| Channel type |
L
| Total number of channel types |
c
l
| Number of detected channels of each type at each node index |
p
| Probability of a particular channel availability at each node |
Probability that there is at least one single channel among c channels between two nodes | |
P
car,c
| Probability that there is at least one common channel among all hops in a route |
λ
| Poisson density of nodes' spatial distribution in the network |
R
l
| Transmission range of a channel of type l |
P
snd
| Signal power at transmitting antenna |
P
r
| Receiving power at distance r |
P
STPCH
| Signal power threshold for preemptive channel handoff |
W
ch, l
| Warning distance for nodes communicating on a channel of type l |
W
link
| Warning distance for preemptive local flow handoff region |
v
relative
| Relative speed |
PCTR,
l
| Received power at channel transmission range of type l |
SHTH,l | Handoff threshold for the preemptive channel handoff |
LHTH | Handoff threshold for the preemptive local flow handoff |
P
SLFTH
| Signal power threshold for preemptive flow handoff |
P
NTR
| Power received at the node transmission range, R
l
|
t
w
| Interval from the warning till the break |
Channel availability time for the channel of type l | |
Channel availability time for the channel of type l available in hop i | |
t
ava,L
| Link availability time |
Location weight for case Di- 1 i and channel of type T
l
| |
h
i,l
| Possibility of using the channel of type l, detected by both nodes belonging to the hop i (H
i
) |
Possibility of using the channel z of type l for communicating in hop i | |
Possibility of using the channel of type l for data transmission in hop i | |
Channel allocation metric for channel z of type l | |
The set of detected channels by the two nodes belonging to the hop i | |
Channel z of type l belonging to the set of detected channels by the two nodes belonging to the hop i | |
The set detected channel that can be used for communication in hop i |
4.1 System description
4.2 Characterization of channel availability and spectrum mobility in CR-MANETs
5 Proposed PIHM algorithm
5.1 The SU's mobility
5.2 The PU's activity dominates
5.3 Spectrum heterogeneity and different channel transmission range
-
Forced intra-pool spectrum handoff: The operation frequency of the SU is changed to another spectrum band in the same spectrum pool. This type of handoff happens because of the appearance of the PU.
-
Forced inter-pool spectrum handoff: The operation frequency of the SU is changed to another spectrum band in a different spectrum pool because of the appearance of the PU.
-
Inter-pool spectrum handoff: The CR user changes its spectrum bands from one spectrum pool to another different spectrum pool. This type of spectrum handoff occurs because of the mobility and channel quality degradation of the SU.
-
Local flow handoff: Due to the SU mobility, there is no channel that can support the data transmission.
6 Implementation of the proposed PIHM algorithm
6.1 Channel and local flow handoff prediction
6.2 Channel and link usage time prediction
Power strength/reception time | ||
---|---|---|
P
3
|
P
2
|
P
1
|
T
3
|
T
2
|
T
1
|
6.3 Channel allocation scheme
6.4 Handoff initiation and connectivity maintenance
-
Node E compares its own available channels Cava,int with the available channels of the local source Cava,locs in HR. The usable channel set in this hop can be shown as follows:(40)
-
Node E determines the channel z, which maximizes the channel allocation metric from the channel set , using (39).
-
Let z be the selected channel, node E updates HR with its own information, the ID of node B as the local source, the ID of node F as the local destination, and its available channel list.
-
Once the CCC is available, it sends the HR to the local destination node F. Finally, this HR will be saved in a handoff table.