IEEE Consumer Electronics Magazine - March 2018 - 47

1. if node=collector node
2. if data collector ! neighbor
3.
send data to data collector
4. end if
5. else if node=normal node
6. if collector node ! neighbor
7.
send sensed data to the collector node
8. else
9.
if source is within ellipse
10.
send data away from the center of the ellipse to
the nearest collector node
11.
else
12.
send data toward the center of the ellipse to
the nearest collector node
13.
end if
14. end if
15. end if

data. The collector node rotates on the predefined elliptical
path and collects the stored sensed data from its neighboring
forwarding nodes, as shown in Figure 7. The data collector is
responsible for data forwarding to the base station based on the
data sensitivity level or distance between them. In the worst
case, the collector node delivers the aggregated collected data
to the base station after one rotation.

THE DATA TRANSMISSION
Two mobile data collectors are placed in the predefined path by
dividing the sensing area into two approximately equal parts.
The mobile data collectors are deployed in either part with the
base station always present at the center of the sensing area.
Both of the mobile data collectors start moving from the base
station to collect data packets from the forwarding nodes at the
time of rotation. These collectors periodically rotate in the elliptical path to collect the data packets from the sensor nodes.
After completing one rotation, the mobile data collectors aggregate the collected data and finally deliver the accumulation of
the collected data back to the base station, as stated in the section, "The Data Collection Phase." A procedure for data collection is shown in Algorithm 2.

PERFORMANCE EVALUATION
Several simulation environments also exist for the IoT and
WSNs [16]. The Castalia simulator in the Ubuntu platform
was used to evaluate the performance of the proposed datarouting technique [17]. The simulation parameters used are
shown in Table 1. The performance of the proposed routing
technique is compared with ring-routing protocol [18].

Table 1. Simulation parameters.
Simulation Parameters

Values

Simulator used

Castalia Simulator (version 3.2)

Network area

600 × 600 m2

Number of nodes

200

Maximum radio transmission
power

0 dbm

Sensibility

-95 dbm

Simulation time

600 s

Medium access control
(MAC) protocol

Tunable MAC

Initial energy of nodes

1,000 mJ

Data collector speed

3, 6, 9, 12, 15 km/h

Number of data collectors

shows the average control packet overhead with varying data
collector speed. The proposed technique reduces the use of
control packets as compared to the ring-routing protocol. In
ring routing, the ring nodes always keep the location of the
sink, which allows for easy retrieval of the sink location.
However, as network operation progresses, there is always
the need for a control packet exchange to repair the ring. An
increase in the distance between the source and sink leads to
higher energy consumption for the increased ring length.

AVERAGE ENERGY CONSUMPTION
The average energy consumption of a node is the energy consumed in transmitting and receiving data packets and control
packets in a network. Energy consumption of routing protocols should be reduced to improve the network effectiveness.
In this experiment, the average energy consumption was
measured by varying the data collector speed from 3 to 15 km/h
in increments of 3 km/h at a constant simulation time of
600 s. The average energy consumption for the proposed
technique is less than the existing standard mobile sink

Average
Control Packet Overhead

Algorithm 2: Collection of data from
the forwarding node by mobile data collectors.

0.1
0.095
0.09
0.085
0.08
0.075
0.07

Existing
3

AVERAGE CONTROL PACKET OVERHEAD
To manage the data collector mobility, sensors transmit the
control packets for rendezvous region construction. Figure 8

Proposed

9
12
Sink Speed (km/h)

FIGURE 8. The variation of the average control packet overhead
with the data collector speed.

MARCH 2018

IEEE Consumer Electronics Magazine

Table of Contents for the Digital Edition of IEEE Consumer Electronics Magazine - March 2018