Simulation - II 10/12/08
(Due at the beginning of
class on
CS G254 Wireless
Networks
This assignment will be
graded out of 50 points.
You could use glomosim
OR qualnet to finish this simulation assignment.
1.
Medium access control.
The goal of this work is to
study the performance of IEEE 802.11
- This is a network consisting of a base station (server)
and multiple static nodes (clients).
- All nodes are within transmission range of each
other. In other words, no hidden or exposed terminal problems in this
network.
- Constant-Bit-Rate is chosen as upper layer
application.
- Each client node starts sending data from second
0, and transmission interval is 4ms. The packet size is 512 bytes. Assume
that each node has an infinite number of packets to send.
- The simulation time is 5 seconds.
- The propagation model is
- UNIFORM node placement.
- Set your simulation terrain to be 500m*500m.
- RADIO-RX-TYPE
RADIO-RX-THRESHOLD 10.0 - TX-POWER 20dBm
- ANTENNA GAIN 0
- RX-SENSITIVITY -81.0dBm
RX-THRESHOLD -81.0dBm - If you use Qualnet, please set the
Change
the number of client nodes from 1 to 6, in steps of 1. Observe how the network
performance changes in terms of the total throughput of base station and
end-to-end delay averaged over all client nodes.
system throughput is defined as the
total number of packets received by the base station.
a)
Brief description
of your simulation procedure. Clearly describe how you define your app.conf. [3]
b)
Plot the node
placement for a network consisting of 6 nodes. [1]
c)
Plot number of clients
vs. system throughput. [4]
d)
Plot number of
clients vs. end-to-end delay averaged over all nodes (Glomo.stat
contains throughtput and end-to-end delay for
individual nodes. You could write a very short shell script to calculate the system
throughput and end-to-end delay.) [4]
e)
Analysis of your
plots to discuss the benefits or disadvantages of 802.11. [3]
2.
Study of network
capacity in grid network.
In
this task, we are going to study the impact of space reuse and route lengths in
grid network. Set up the network scenario as follows
·
Edit nodes.input to define a grid network consisting of 4, 9 or
16 nodes. The distance between two adjacent nodes is 100m. (you need to do
simulation for
all 3 scenarios)
·
Static routing is
applied. ROUTES.IN could be downloaded from here.
glomosim
qualnet
·
Set simulation
time to 10 minutes.
·
Use 802.11 as
·
Define
·
Set up other parameters
the same as in task2.
In
your simulation, study the three grid topologies illustrated in the above
figure.
Each node randomly chooses its destination among all other nodes in the grid network
at the beginning of simulation, and keeps sending packets to this node through
the whole simulation. The upper layer
At
the end of the simulation, calculate system throughput and end-to-end delay
averaged over all nodes.
System throughput is defined as the total number of packets that have
been successfully transmitted to destinations in the whole network
average End-to-End delay is defined as the end-to-end delay averaged
across all nodes.
a)
Plot average
system throughput vs. size of grid. [6]
b)
Plot average
end-to-end delay vs. size of grid. [6]
c)
According to
your simulation result, analyze how the network performance changes as the grid
network expands. [3]
3.
Capacity of
wireless networks
a.
State the main
assumptions in the Gupta-Kumar model. Prove an upper bound on the
per-connection bandwidth and show that it vanishes as the number of users
increase. What is the practical implication of this result? [6]
b.
What are the
assumptions underlying the Grossglauser-Tse mobility
model? Give a heuristic argument that explains why the per-connection bandwidth
does not vanish. [4]
4.
Geometry of
cells.
a.
Prove that the
only regular polygons with n sides that tessellate the plane are the triangle
(n=3), square (n=4) and hexagon (n=6). Why is the hexagon the shape of choice
for cell networks? [4]
b.
What is the
channel reuse factor? Prove that the channel reuse factor can only take values
of the form i2 +j2 + ij, for
nonnegative integers i, j. [6]