0
1
2
3
4
5
6
Average energy per
packet (nJ)
BFT
Mesh-1
Mesh-2
MoT
0.0
0.3
0.5
0.8
Locality factor
103
Evaluation of Network-on-Chip Architectures
Figure 4.26
Average energy consumption per packet received at network saturation under different
locality factors.
decreases at high locality factors. It has been observed that the overall energy
consumption decreases with increasing locality factors for all the networks.
Due to the relatively lesser number of FIFOs and inter-router links, the
energy consumption of Mesh-2 network turns out to be the least for all locality factors. The energy consumption of BFT and Mesh-2 networks are almost
the same under uniform distribution, as shown in Figure  4.25. However,
due to higher throughput, Mesh-2 network has lesser average energy consumption per packet reception at saturation, as shown in Figure  4.26. The
throughput of the BFT network is significantly lesser than that of Mesh-2
and MoT networks at highly localized traffic, which causes higher average
energy consumption per packet. As Mesh-1 network has higher number of
FIFOs and inter-router links, and its throughput is lesser for any locality factor, simulation result shows that the average energy consumption per packet
of the Mesh-1 network is inferior to others.
Although the MoT-based network requires more FIFOs and inter-router
links than Mesh-2 networks, at high locality factor, the toggle of the data in
stem and root routers of MoT networks is significantly less. At a high locality
factor, throughputs of both the networks are almost the same. As a consequence, the average energy consumption per packet reception in the MoT
network is slightly higher than that in Mesh-2 network, but lesser than other
networks considered here.
4.7 Simulation Results and Analysis of MoT Network
with Virtual Channel Router
The usage of WH router in NoC design leads to performance degradation due
to contention in the network. Virtual channel (VC) router, however, mitigates
the network contention problem, to some extent, by using multiple FIFOs at