Post on 18-Jan-2018
description
Joint Base Station and Relay Station Placement for IEEE 802.16j Networks
Hsiao-Chen Lu and Wanjiun LiaoDepartment of Electrical Engineering, National Taiwan University,Taiwan
IEEE GLOBECOM 2009
Outline Introduction System Model Problem Definition and Formulation The Two Stage BS and RS Deployment Algorithm Computational Experiments Conclusion
Introduction IEEE 802.16j
Network components Base station (BS) Subscriber Station (SS) Mobile station (MS) Relay station (RS)
BS
SS
SS
MS
RS
Transparent Model
RS
Non-Transparent Model
RS
Introduction IEEE 802.16j – Relay Station placement issue
Low cost Throughput enhancement Coverage extension
BS
MS
MS
Introduction-Motive and Goal Network planning problem
Deploying a number of BSs and RSs to serve mobile stations distributed arbitrarily in a given geographic area.
…
…Deployment
Let the cost is within the budget and the system capacity is maximized.
System Model
Demand Node (di)
Wi = The number of the MS.
Wi = 10
Other Assumption Only consider at most two-hop relaying. Transparent and non-Transparent model.
Candidate site for BS : bi
Candidate site for RS : ri
= 6
Problem Definition and Formulation The Joint BS and RS Deployment Problem (JBRDP)
Given the geographic area in which DNs are distributed, we want to determine the locations for a number of BSs and RSs, with the total cost within the pre-determined budget, such that each DN is covered by at least one BS or RS and the system capacity
can be maximized.
di
= 10 Mbps
60 Mbps
Problem Definition and Formulation Subject to constraints:
b1= 1 b2= 0 b3= 0
b4= 0 b5= 0 b6= 1
b7= 0 b8= 1 b9= 0
r1= 0 r2= 1 r3= 0
r5= 0 r6= 0 r7=0
r9= 0 r10= 1 r11= 0
r4= 0
r8= 1
r12= 1
r13= 1 b14= 0 r15=0 r16= 0
(1) (2)
= 1
Problem Definition and Formulation Subject to constraints:
(3)
(4)
dj
bi = 1
= 1ri = 1
Problem Definition and Formulation Subject to constraints:
ri = 1 rj = 1
(5)
The Two Stage BS and RS Deployment Algorithm To find the placement of BSs and RSs for a specific deployme
nt profile ( nB , nR ).
The number of BSs deployed in the network.
The number of RSs deployed in the network.
(3)
The Two Stage BS and RS Deployment Algorithm
First Stage : BS Deployment
Second Stage : RS Deployment
input
( nB , nR )
outputDeployment vector:B = [b1 b2 ... bN ] and R = [r1 r2 ... rM].
The Two Stage BS and RS Deployment Algorithm
First Stage : BS Deployment Second Stage : BS Deployment
First Stage : BS Deployment Determine a set of BS locations such that the longest distance between a DN and i
ts nearest BS is minimized . The number of BSs deployed is equal to nB .
The Two Stage BS and RS Deployment Algorithm
NP-complete problem: the k-supplier problem [9]
[9] “A unified approach to approximation algorithms for bottleneck problems,” Journal of the ACM, July 1986.
Vsup…
Vcust…
Weighti
= Distancei
bi
di
B = nB
The Two Stage BS and RS Deployment Algorithm Second Stage : RS Deployment
Achieve rate gain
Computational Experiments Simulator: The C++ program Simulation parameters
The coverage radius of a BS 7km
The coverage radius of a RS 4km
LI ( The interference threshold for RSs ) 3km
The deployment budget 80 units
The cost of a BS 10 units
The cost of a RS 3 units
25 km
25 km
1 km1 km
Computational Experiments
Computational Experiments The network aggregate data rate versus the number of BSs
and RSs deployed for the MS hotspot scenario
Computational Experiments The fairness index versus the number of BSs and RSs deplo
yed for the MS hotspot scenario.
Conclusion This paper Formulate the joint BS and RS deployment
problem under budget and coverage constraints as a capacity maximization problem.
Design a two-stage network deployment algorithm which considers both issues of capacity enhancement.
The numerical results indicate that deploying relay stations can enhance system capacity and fairness under the condition that the number of base stations deployed is not too small.
Thank you very much ~