1 Predictive Group Handover Scheme with Sub-Channel Borrowing for IEEE 802.16j- enabled Vehicular...
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Transcript of 1 Predictive Group Handover Scheme with Sub-Channel Borrowing for IEEE 802.16j- enabled Vehicular...
第( 1)页 http://WM.tongji.edu.cn
Predictive Group Handover Scheme with Sub-Channel Borrowing for IEEE 802.16j-
enabled Vehicular Networks
Broadband Wireless Communication and Multimedia Laboratory,
Tongji UniversityLianhai Shan
第( 2)页 http://WM.tongji.edu.cn
Outline
• Features of Group Handover and Problems Statement
• Proposed Scheme: PGHO-CB
• Performance Analysis
• Simulation Scenario and Result Analysis
• Conclusion and Future Work
第( 3)页 http://WM.tongji.edu.cn
Mobile RS Application Scenario
Relay Station:
Enhance the signal strength
Extend the coverage
第( 4)页 http://WM.tongji.edu.cn
Group Handover Scenario
Backbone networks
Mobile RS
Mobile direction
Internet
…
MS1
MS3MS2
MS
MSMS
Serving BS Target BS
Broadband Wireless Access using IEEE802.16j for Mobile Multi-hop WiMAX
SINR of a neighbor BS is larger than the current serving BS, (the hysteresis margin, threshold), then the handover of group users will happen.
第( 5)页 http://WM.tongji.edu.cn
Problems for Group Users
• Heavy burden for BS
• Long system delay in the GHO process
• Handover dropping probability
第( 6)页 http://WM.tongji.edu.cn
Outline
• Features of Group Handover Problems Statement
• Proposed Scheme: PGHO-CB
• Performance Analysis
• Simulation Scenario and Result Analysis
• Conclusion and Future Work
第( 7)页 http://WM.tongji.edu.cn
GHO Flow Chart
Scanning neighboring BSs, get the optimal BS(#B) as the target BS according to the acquired location and mobile information, target BS get the detailed information of MSs and prepare the resources
Mobile RS MR-BS #A(serving)
MR-BS #C(candidate)
MR-BS #B(candidate/target)
MOB_SCN-REQ
MOB_SCN-RSP
MR_NBR-INFO
Association
BS_ID= BS#B)
(Recommended BS= BS #B)
MOB_RSHO-REQ
MOB_RSHO-RSP
MOB_RSHO-IND(Time= L frames)
RNG_RS-REQ
RNG_RS-RSP (New CID for MS#1…MS#n)
Normal Operation and Data Transfer
Serving BS realease
Resource R
etain Tim
er
Network reentry after HOHandover Delay time
RS calculates the position information, compares it with the position report database and get the exact position and mobile direction in certain time
MS#1… #n
in Mobile RS
MOB_NBR-ADV
MOB_SCN-REQ
MS_SCN-INF
MS_SCN-ACK
MOB_SCN-RSP
Handover Calls Admission Control(HO Pre-notification Process for MS#1…MS#n through Backbone )
MOB_MSHO-REQ
MOB_BSHO-RSP
MOB_HO-IND(Time= L frames)
RNG-REQ
RNG-RSP
Serving BS realease
MOB_MSHO-REQ
MOB_BSHO-RSP
…
Can be Omitted by GHO
T1
T2
T3
第( 8)页 http://WM.tongji.edu.cn
Proposed Scheme
Predictive Group Handover (PGHO)• Location and moving direction information
Channel Borrowing (CB)• Borrowing Channels from the existing service in the target BS
by decreasing the QoS level.
PGHO-CB: Predictive Group Handover with sub-channel borrowing
第( 9)页 http://WM.tongji.edu.cn
Proposed Scheme
Mobile directionserving BS ID, average dwelling time,
next target BS ID Count
On route (ID_1, T100, ID_3) 22
On route (ID_1, T60, ID_4) 5
On route …… …
Return route (ID_8, T80, ID_6) 20
Return route (ID_8, T120, ID_7) 4
Return route … …
Movement History Database
Large vehicles moving routes is fixed such as light rails, subways.
第( 10)页 http://WM.tongji.edu.cn
Proposed Scheme• Erlang-B formula reversely to estimate the number of sub-
channel required
),(
!)(
!)(
0
MTf
iT
MT
PM
i
i
M
),( _Re RRqR MBfP
),( _Re NNqN MBfP
avbreqbor BBB Result:
NP: CBP of nrtPS in a BS;
: CBP of rtPS in a BS;RP
reqB is the number of sub-channels needed for the coming GHO
avbB is available sub-channels in the target BS
第( 11)页 http://WM.tongji.edu.cn
Proposed Scheme• Sub-Channel Borrowing (CB) for PGHO
Detailed CB is within my published papers, will appear in LNCS of Apweb’09.
第( 12)页 http://WM.tongji.edu.cn
Outline
• Features of Group Handover Problems Statement
• Proposed Scheme
• Performance Analysis
• Simulation Scenario and Result Analysis
• Conclusion and Future Work
第( 13)页 http://WM.tongji.edu.cn
Single Handover Model0,0
X,Y
1,1
0,N
0,T
0,1
M,0S,01,0hoRnR __
hoN
nN
__
hoRnR __ hoRnR __ hoR _hoR _
RR )(2 RR )( RRS ))(1( RRS )( RRM
NN
hoN
nN
__
)(2
NN
hoN
nN
__
)(2
NN
hoN
_
))(1
(N
NT
hoN
_
)(
NN
N
hoRnR __
RR
hoN
nN
__
NN
hoRnR __
)( RRX
hoRnR __
)( RR
hoRnR __
)(2 RR
hoN
nN
__
)(2
NN
hoN
nN
__
)(
NN
Y
NR
RN
R
R
N
R
bbXBY
bbYBX
bBN
bBM
bBT
bBS
/*
/*
/
/
/
/
min_
min_
2-D Markov state transition diagram
第( 14)页 http://WM.tongji.edu.cn
Single Handover • New calls blocking probability (CBP) of rtPS and nrtPS
• handover blocking probability (HBP) of rtPS and nrtPS
rtPS
nrtPS
rtPS
nrtPS
第( 15)页 http://WM.tongji.edu.cn
Proposed Group Handover
Markov transition diagram for a Single MS using PGHO scheme
0,0,0
X,Y,0
1,1,0
0,N,0
0,T,0
0,1,0
M,0,0S,0,01,0,0shoRsnR __
sho
Nsn
N_
_
shoR _
RR )(2 RR )( RRS ))(1( RRS )( RRM
NN
)
(2N
N
)(2
NN
sho
N_
))(1
(N
NT
sho
N_
)(
NN
N
shoRsnR __
RR
NN
shoRsnR __
)( RRX
shoRsnR __
)( RR
shoRsnR __
)(2 RR
)(2
NN
sho
Nsn
N_
_
)
(N
NY
min_min_
min_min_
min_
min_
min_
min_
/)*(
/)*(
/)(
/)(
/)(
/)(
NRg
RNg
Ng
Rg
Nrevg
Rrevg
bbXBBY
bbYBBX
bBBN
bBBM
bBBBT
bBBBS
shoRsnR __ shoRsnR __ shoR _
sho
Nsn
N_
_
sho
Nsn
N_
_
sho
Nsn
N_
_
sho
Nsn
N_
_
0,0,1
Xk,Yk,1
k,k,1
0,Nk,1
0,Tk,1
0,k,1
Mk,0,1Sk,0,1k,0,1ghoRgnR __
gho
Ngn
N_
_
ghoR _
)( RRk )(2 RRk )( RRSk )()1( RRkS )( RRMk
)(
NN
h
)(
2N
Nk
)
(N
NTk
gho
N_
)(
)1(
NN
kT
gho
N_
)(
NN
Nk
)( RRk
)(
NN
h
shoRsnR __
)( RRXk
shoRsnR __
)( RRk
)(2 RRk
)(
2N
Nk
sho
Nsn
N_
_
)(
NN
Yk
min_min_
min_min_
min_
min_
min_
min_
/)*(
/)*(
/)(
/)(
/)(
/)(
NRs
RNs
Ns
Rs
Nrevs
Rrevs
bbXkBBYk
bbYkBBXk
bBBNk
bBBMk
bBBBTk
bBBBSk
gho
Ngn
N_
_
gho
Ngn
N_
_
sho
Nsn
N_
_
gho
Ngn
N_
_
ghoRgnR __ ghoRgnR __ ghoR _
ghoRgnR __ ghoRgnR __
Markov transition diagram for a Group MSs using PGHO scheme
第( 16)页 http://WM.tongji.edu.cn
Proposed Group Handover
''_
'_ ),(),(
_ )1,,()0,,(nRRSRSnRBSBS Cji
RSRSRSCji
BSBSBSnR jipjipP
}|),{('_ RrevNRSRRSNBSRBSnR bBBbjbibjbijiC
}|),{(''_ RrevNRSRRSNBSRBSnR kbBBbjbibjbijiC
''
_'
_ ),(),(_ )1,,()0,,(
nNRSRSnNBSBS CjiRSRSRS
CjiBSBSBSnN jipjipP
}|),{('_ NrevNRSRRSNBSRBSnN bBBbjbibjbijiC
}|),{(''_ NrevNRSRRSNBSRBSnN kbBBbjbibjbijiC
• New calls blocking probability (CBP) of rtPS and nrtPS
第( 17)页 http://WM.tongji.edu.cn
Proposed Group Handover
''_
'_ ),(),(
_ )1,,()0,,(hoRRSRShoRBSBS Cji
RSRSRSCji
BSBSBShoR jipjipP
}|),{( min_min_min_min_min_'
_ RNRSRRSNBSRBShoR bBbjbibjbijiC
}|),{( min_min_min_min_min_''_ RNRSRRSNBSRBShoR kbBbjbibjbijiC
''
_'
_ ),(),(_ )1,,()0,,(
hoNRSRShoNBSBS CjiRSRSRS
CjiBSBSBShoN jipjipP
}|),{( min_min_min_min_min_'
_ NNRSRRSNBSRBShoN bBbjbibjbijiC
}|),{( min_min_min_min_min_''
_ NNRSRRSNBSRBShoN kbBbjbibjbijiC
• handover blocking probability (HBP) of rtPS and nrtPS
第( 18)页 http://WM.tongji.edu.cn
Adaptive HO CAC Delay
• : represents the handover CAC adaptive factor
• : represents exponential factor, decided by the different service types
• : the highest speed
• : the largest handover CAC delay time
• : the least handover CAC delay time as
nvvdelayCAC etttT ))(( 1/
minmaxmax_max
max/ vvr
n
maxv
maxt
mint
第( 19)页 http://WM.tongji.edu.cn
HO Dropping under Different Velocity
: HBP in the handover CAC process
: the time of handover CAC process of each time
: practical delay of handover CAC process
)1/( _'
_ failnegocacdelayCAC RTT
failnegoR _
cacT
'_ delayCACT
delayCACdelayCAC TT _'
_ If , handover QoS will reduce
max'
_ tT delayCAC If , handover dropping will happen
the longest handover CAC delay that can ensure the connection maxt
第( 20)页 http://WM.tongji.edu.cn
Outline
• Features of Group Handover Problems Statement
• Proposed Scheme
• Performance Analysis
• Simulation Scenario and Result Analysis
• Conclusion and Future Work
第( 21)页 http://WM.tongji.edu.cn
Simulation Parameterparameters value
Number of Cells 19
Operating Frequency 2500MHz
Duplex TDD
System Channel Bandwidth 10MHz
BS Height 32 meters
Mobile Terminal Height 1.5 meters
BS Antenna Gain 15 dBi
MS Antenna Gain -1 dBi
BS Maximum Power Amplifier Power 43 dBm
Thermal Noise -174 dBm/Hz
Sampling Frequency 11.2MHz
FFT Size (NFFT) 1024
Sub-Carrier Frequency spacing 10.94kHz
Frame Duration(TTI) 5 milliseconds
Number of OFDMA Symbols 48
Propagation Model COST231-Hata
第( 22)页 http://WM.tongji.edu.cn
Simulation Parameter
parameters valueNumber of Channels 30
Dwelling time 0.5
Call completion rate = 0.5
new call arrival rates of rtPS
new call arrival rates of nrtPS
System traffic load
channel number of one rtPS (min-max) 2-4
channel number of one nrtPS (min-max) 1-3
radius of BS coverage 1.28 km
第( 23)页 http://WM.tongji.edu.cn
New calls and HO blocking probability
0 2 4 6 8 10 12 140
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Traffic load (new calls/min)
Ne
w c
all
blo
ckin
g p
rob
ab
ility
of s
yste
m
Average user number in a MRS equels 3
nrtPS with SHO scheme
rtPS with SHO scheme
nrtPS with GHO scheme
rtPS with GHO scheme
0 2 4 6 8 10 12 140
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Traffic load (new calls/min)
Ha
nd
ove
r b
lock
ing
pro
ba
bili
ty o
f sys
tem
Average user number in a MRS equels 3
nrtPS with SHO scheme
rtPS with SHO scheme
nrtPS with GHO scheme
rtPS with GHO scheme
第( 24)页 http://WM.tongji.edu.cn
Handover dropping probability
20 40 60 80 100 1200
5
10
15
20
25
Mobile RS velocity(km/h)
Ave
rag
e h
an
do
ver
dro
pp
ing
pro
ba
bili
ty(%
) Traffic load equals 6 and average user number in a MRS equels 5
rtPS(SHO scheme)
nrtPS(SHO scheme)
rtPS(GHO scheme)
nrtPS(GHO scheme)
第( 25)页 http://WM.tongji.edu.cn
Average handover delay
20 40 60 80 100 120
45
50
55
60
65
70
75
Mobile RS velocity(km/h)
Ave
rag
e h
an
do
ver
de
lay
in M
RS
(ms) Traffic load equals 6 and average user number in a MRS equels 5
rtPS(SHO scheme)
nrtPS(SHO scheme)rtPS(GHO scheme)
nrtPS(GHOscheme)
第( 26)页 http://WM.tongji.edu.cn
Outline
• Features of Group Handover Problems Statement
• Proposed Scheme
• Performance Analysis
• Simulation Scenario and Result Analysis
• Conclusion and Future Work
第( 27)页 http://WM.tongji.edu.cn
Conclusion
• PGHO-CB predict the target BS for mobile RS
• Target BS prepare the needed resource for HO using the Sub-Channel Borrowing
• Decrease the HDP significantly of group handover
第( 28)页 http://WM.tongji.edu.cn
Future Work
• Two-level Channel Reallocation for Group Handover after Sub-channel Borrowing
• System Performance of GHO
第( 29)页 http://WM.tongji.edu.cn
ThanksQ&A