Hi .....
I am a 4th year student( B Tech) working on my project " Multi gateway
Association in wireless mesh networks". I am unable to write the codes for
my project for developing graphs which primarily includes showing the
throughput benefits of using multiple gateways over single gateway.
*The details of my project are: *
Most traditional models of wireless mesh networks involve a mobile device
connecting to the backbone through one of the available gateways in a
wireless mesh network. In this paper, an alternate model, in which mobile
devices
are allowed to connect through more than one of the available gateways is
proposed. I have read the documentation on ns2 but i am not able to write
codes for my project. The network simulator ns2 is used for the
experiments.CBR(Constant Bit Rate) is used as the data generating
application. The routes are computed using a shortest path algorithm in a
centralized manner. The total number of nodes is 70 which includes 4
gateways, 61 routers and 5 clients. The topology considered is a 1000m X
1000m grid. The position of the gateways is fixed at the coordinates
(200,200),(200,900),(900,200) and (900,900).
The position of the routers is uniformly distributed within the grid. The
position of the clients is also uniformly distributed within the grid. A
bandwidth of 2Mbps is used and all nodes operate on the same channel. The
transmission range is set to 250m. Unless otherwise stated, the number of
users is 5 and the loads of the users are
100Kbps,100Kbps,100Kbps,100Kbps,2Mbps.
I would be very grateful if anyone can provide ome help.The gateway
association algorithm is as follow:
Variables:
1 g: Number of gateways,c:Current Node id,f:Flow id,
2 W: Channel Bandwidth, F : Number of existing flows
3 Pi: Path from node c to gateway i,lc:Load of flow c
4 BL(Pi): Bottleneck Load of path Pi,
5 FSi Flow Set of Path Pi, OFS: Overall Flow Set
6 Rate(f; g): Sending Rate of flow f to gateway g,
7 Rate(f):Aggregate Sending rate of flow f,
8 FR(f; n): Rate of flow f passing through node n,
9 AB(i) : Available Bandwidth on the path to gateway i
Given:
10 Gateways,nodes,routers,2-hop contention regions,
11 Shortest Paths,Bandwidths, Existing flows and loads
Compute BL(Pi):
INPUT:Pi
OUTPUT:BL(Pi)
For each node j in Path Pi
AL(j) = Summation of interference region of node j FR(fk; j)
BL(Pi) = max(AL(j))
MAIN
INPUT:New flow f c with load lc
OUTPUT:Rate(i; j) : i = 1 to F + 1 , j = 1 to g
For i = 1 to g
Pi = ComputeShortestpath(i)
BL(Pi) = ComputeBL(Pi)
AB(i) = W - BL(Pi)
IF lc < Summation of AB(i) ( limits from i to g)
do while (lc has been alloted)
Sort in descending order AB(i) : i = 1 to g
Allocate load from the gateway with largest AB(i)
Update AB(i)
ELSE
Identify all bottlenecks for the paths P1 to Pg
F(Si) = (intersevtion of Flow sets of maximum bottleneck on path i)
OFS = ( union of F(Si))
Do
Sort OFS in descending order of Rate(f)
Choose Flow fk in OFS with maximum Rate(f)
Decrease Rate(fk; i) i : fk BL(Pi)
and Rate(fk) by 1 unit
Increase Rate(fc;m) [ m : Pm contains the maximum
bottleneck of fk] and Rate(fc) by 1 unit
Until (Rate(fc) = lc or Rate(fc) = Rate(fk))
And the scheduling algorithm is as follows:
Variables:
g: Number of gateways,c:Current Node id,P: Packet Size,
di : End-to-end propagation and queuing delay on path ’i’
ri: sending rate on path ’i’ ,Tdi:Total delay to gateway i
Pi: Path between current node and gateway ’i’,
a(i) Normalized delay for path i,b(i):Integral scaling of a(i)
RT(i; j): Receive Time of the ith packet destined to gateway j,
ID : Vector of gateway Identifiers
INPUT:
Delays and rates to each gateway
OUTPUT:
Number of packets to each gateway
Window
For each gateway
Tdi = di + P/Ri
a(i) = Tdi/max(Tdi)
b(i) = Integer(a(i))
NP = summation of b(i ) ( limits i to g)
SCHEDULE
INPUT: Number of packets b(i)
OUTPUT: Destination IDs for each pkt and Tx sequence
For j = 1 to g
For k=1 to b(i)
RT(i; j) = ( 1/rj+ dj ) * k
ID=SortID(RT(i; j)
I would really be very thankful for the help..
