View
214
Download
0
Category
Tags:
Preview:
Citation preview
Bader Al-Manthari, Nidal Nasser, and Hossam Hassanein,“Downlink Scheduling With Economic Considerations for Future Wireless Networks,” IEEE TRANSACTIONS ON VEHICULAR TE
CHNOLOGY, Vol. 58, No. 2, FEBRUARY 2009.
Advisor: Yeong-Sung LinStudent: Chiu-Han Hsiao
Department of Information ManagementNational Taiwan University
Taipei, Taiwan, R. O. C.
2010/05/18 2OPLAB
Outline Introduction Background Study
Problem Description and System Model
Centralized Downlink Packet Scheduler (CDPS)
Performance Evaluation
Experiment Result
Conclusion
2010/05/18 3OPLAB
Introduction(1/2)
3G Universal Mobile Telecommunication System (UMTS)(2Mbps)
High-Speed Downlink Packet Access (HSDPA) (3.5G) can theoretically support up to 14.4 Mbps, which is seven times higher than the data rate offered by UMTS
A key component of radio-resource management (RRM) is packet scheduling, which is responsible for distributing the shared radio resources among the mobile users
we propose a novel centralized downlink packet scheduler (CDPS) scheme to be implemented at the base stations of future wireless cellular systems
2010/05/18 4OPLAB
Introduction(2/2)
CDPS utilizes an opportunity cost function that allows service providers to control its degree of fairness and hence control the system capacity
CDPS is designed to balance between the requirements of connections (e.g., throughput, fairness, etc.) and the requirements of service providers (e.g., revenues)
CDPS can be configured to reduce to the maximum carrier-to-interference ratio (Max CIR) and proportional fairness (PF) schemes
2010/05/18 5OPLAB
Background Study
2010/05/18 6OPLAB
Multiple Access Methods
Multiple users share the available spectrum
2010/05/18 7OPLAB
What is “IMT-2000”
IMT-2000 (Internet Mobile Telecommunications-2000) is the personalized global multi-media service, which unifies all the various mobile telephone system specs
Services– global roaming service
– multimedia communications
This is “ 3rd Generation Mobile Communication System”
2010/05/18 8OPLAB
IMT-2000
ITU (International Telecommunication Union)IMT-2000
• Year 2000 Ready
• Operate at 2000 MHz
• Provide 2000K bps Data Rate
3G Data Rate Requirement• Vehicular -- 144 Kbps
• Pedestrian --- 384 Kbps
• Indoor --- 2Mbps
2010/05/18 9OPLAB
IMT-2000 Evolution
2010/05/18 10OPLAB
IMT-2000 Evolution
PDC
GSM
ARIB (W-CDMA)
GPRS
UTRA (W-CDMA)
EDGE
Wideband CDMA
TD-CDMA(TDD)
MulticarrierMulticode
W-CDMA(FDD)
AMPS IS-54
cdmaOne(IS-95)
IS-136
136+
136 HS
UWC-136
cdma2000
IS-95B
PDC
GSM
ARIB (W-CDMA)
GPRS
UTRA (W-CDMA)
EDGE
Wideband CDMA
TD-CDMA(TDD)
MulticarrierMulticode
W-CDMA(FDD)
TD-CDMA(TDD)
MulticarrierMulticode
W-CDMA(FDD)
AMPS IS-54
cdmaOne(IS-95)
IS-136
136+
136 HS
UWC-136
cdma2000
IS-95B
AMPS IS-54
cdmaOne(IS-95)
IS-136
136+
136 HS
UWC-136
cdma2000
IS-95B
• AMPS: Advanced Mobile Phone System• GSM: Global Systems for Mobile Comm.• GPRS: General Packet Radio Service• PDC: Personal (or Pacific) Digital Comm.• EDGE: Enhanced Data rates for GSM
(or global) Evolution• UTRA: UMTS Terrestrial Radio Access
• IEEE Spectrum, Aug. 1999 (Modified)
2010/05/18 11OPLAB
IMT-2000 Terrestrial RTT Standardization
CDMA2000 (North America)– Based on Qualcom cdmaOne
– Support multi-carrier (MC)
– Use IS-41 to accomplish the core network compatibility
TD-SCDMA (Mainland)– 大唐電信 and Siemens
– TDD-based
– Requirement : time synchronization
– Limit coverage area of BS
WCDMA/UMTS (Japan and Europe)– NTT DoCoMo develops WCDMA
– Core network is based on GSM system
– UTRA (UMTS Terrestrial Radio) proposed by Europe is similar as WCDMA
2010/05/18 12OPLAB
Network Upgrade Comparison: CDMA2000 1x vs. GPRS / W-CDMA
SGSN: Serving GPRS Support Node
GGSN: Gateway GPRS Support Node
MSC: Mobile Switching Center
2010/05/18 13OPLAB
New Terms
WCDMA/UMTS Terms– BTS → Node B (NB)
– BSC → RNC (Radio Network Controller)• New job : RRM (Radio Resource Management)
Radio BearersChannels
– Logical Channel
– Transport Channel
– Physical Channel
Data forwarding direction– Uplink (reverse link)
– Downlink (forward link)
2010/05/18 14OPLAB
3G Frequency Allocation in Taiwan
E
825
E
845
870
890 MHz
A BCBA C D D BA C D
191
5
20
197
5
35
45
60
201
0
202
5
15
20
ITU IMT-20001885MHz 2025MHz
ITU IMT-20002110MHz 2200MHz
21
10
216
5
25
35
50 MHz
3G 執照 頻寬 頻帶 (MHz)
A 2 x 15 MHz + 5 MHz 1920 ~ 1935, 2110 ~2125, 1915 ~ 1920
B 2 x 10 MHz + 5 MHz 1935 ~ 1945, 2125 ~ 2135, 2010 ~ 2015
C 2 x 15 MHz + 5 MHz 1945 ~ 1960, 2135 ~ 2150, 2015 ~ 2020
D 2 x 15 MHz + 5 MHz 1960 ~ 1975, 2150 ~ 2165, 2020 ~ 2025
E 2 x 20 MHz 825 ~ 845, 870 ~ 890
Apple - iPhone - 技術規格.htm
2010/05/18 15OPLAB
WCDMA Standards
3GPP– www.3gpp.org
WCDMA– FDD mode– TDD mode
Release– R98 (1998)– R99 (200003 freeze) --- WCDMA– R4 (200103 freeze)– R5 (2002 freeze) --- HSDPA– R6 (2003 freeze) --- HSUPA– R7 (2007 freeze)– R8 (2008 freeze) --- LTE– R9 (ongoing)– R10 (ongoing) LTE: Long Term Evolution
2010/05/18 16OPLAB
History (1/2)
Release 98 (1998)– This and earlier releases specify pre-3G GSM networks
Release 99 (2000 Q1)– Specified the first UMTS 3G networksfirst UMTS 3G networks, incorporating a CDMA
air interface
– USIM : mutual authentication (AKA)Release 4 (2001 Q2)
– Originally called the Release 2000 - added features including an All-IP Core Network
Release 5 (2002 Q1) – Introduced IMS and HSDPAHSDPA
Release 6 (2004 Q4 )– Integrated operation with WLAN networks and adds HSUPAHSUPA,
MBMS, enhancements to IMS such as Push to Talk over Cellular (PoC)
2010/05/18 17OPLAB
History (2/2)
Release 7 (2007 Q4)– Focuses on decreasing latency, improvements to QoS and real-t
ime applications such as VoIP – also focus on HSPA+HSPA+ (High Speed Packet Access Evolution), M
IMO, SIM high-speed protocol and contactless front-end interface (Near Field Communication enabling operators to deliver contactless services like mobile payments), EDGE Evolution.
Release 8 (In progress, not ready before Mar 2009)– LTELTE, All-IP Network (SAE).All-IP Network (SAE). It constitutes UMTS as an entirel
y IP based fourth-generation network. Release 9 (In progress, expected to be frozen in Dec 200
9 )– SAES Enhancements, WiMAX and LTE/UMTS Interoperability
Release 10 (In progress) – LTE-AdvancedLTE-Advanced
2010/05/18 18OPLAB
3GPP Development Progress
Functionality
Time1999 -12 2001 -03 2002 - 03/06
Release 1999Release 1999
Release 4Release 4
Release nRelease n
Release 5Release 5
UTRA FDD/TDD
modes, USIM,
AMR speech
codec, MMS,
LCS,
CAMEL etc.
LCR TDD,
UTRA FDD
repeater function,
700MHz support
for GERAN
IMS phase 1,
HSDPA,
Wideband AMR,
IP transport
in UTRAN
WLAN/UMTS
Interworking ,
IMS phase 2
Release 6Release 6
2003/12
OFDM?
MIMO?
EDCH?
IMS further
Phase?
Time1999 -12 2001 -03 2002 - 03/06
Release 1999Release 1999
Release 4Release 4
Release nRelease n
Release 5Release 5
,
Release 6Release 6
2003/12- - -
Release 1999Release 1999
Release 4Release 4
Release nRelease n
Release 5Release 5MBMS,
,
Release 6Release 6
HSUPA,
2010/05/18 19OPLAB
3GPP’s Evolution/Revolution Towards 4G
3GPP R4(WCDMA) 3GPP R5
(+HSDPA)
3GPP R5(+HSDPA)
3GPP R63GPP R6(+HSUPA)
3GPP R7(+MIMO)
3GPP R7(+MIMO)
IMT - 2000
2001/11/04 2002/06/24
EnchancedIMT - 2000
2003/09/26 2005/01/04
NewMobileAccess
R8LTE
OFDMA
3GPP R4 3GPP R5 3GPP R6 3GPP R7 3GPP R8Data Rate
(peak)
Systems
Forward Link
Reverse Link
2 Mbps
384 Kbps
> 10 Mbps
384 Kbps
> 10 Mbps
> 2 Mbps
> 20 Mbps
> 5 Mbps
100 Mbps
20 Mbps
2010/05/18 20OPLAB
Radio Resource Management
CDPS is proposed
2010/05/18 21OPLAB
Channel quality condition for scheduling decisions
2010/05/18 22OPLAB
Packet Scheduler Model
2010/05/18 23OPLAB
System Formulation
we emphasize recent scheduling schemes for data (non–real-time) services in future wireless cellular networks
the base station simultaneously serves n connections n ≥ 1 and selects one or more connections for transmission in a frame of some fixed time duration
These PDUs are stored in the transmission queue of the corresponding connection in a first-in–first-out fashion
2010/05/18 24OPLAB
Utility Function
The user’s i (1 ≤ i ≤ n) preferences at time t as perceived by the service provider can be expressed by a utility function Ui(Xi1(t),Xi2(t), . . . , Xim(t)), – where n is the total number of users’ connections in the
system, – Xi1(t), . . . , Xim−1(t) are the chosen quantitative measures
of the user connection’s preferences in this system such as the average throughput, current data rate, average delay, etc.,
– Xim(t) is a fairness measure that represents how fair the scheduling scheme is to the user connection, and m is the maximum number of chosen quantitative measures.
We assume that the utility function is additive
2010/05/18 25OPLAB
Objective Function
OCi(t) is the opportunity cost of serving connection iat time t, and K is a predefined constant value
2010/05/18 26OPLAB
Cobb–Douglas Utility Function for Downlink Scheduling
Cobb-Douglas生產函數:簡稱 C-D生產函數
最簡單之形式如: Q = AKαLβ
式中 Q:產出量, K:資本使用量, L勞動使用量, A 、 α 及 β表固定常數,其數值可由實際統計資料估計出
2010/05/18 27OPLAB
Cobb–Douglas生產函數
1. 若 α +β>1,則此生產為遞增的規模報酬;即若所有生產要素按相同比例增加,則產量增加的比例大於生產因素增加的比例。如:Q = 20K0.7L0.6
2. 若 α +β=1,則此生產為固定的規模報酬;即產量增加的比例等於生產因素增加的比例。例: Q = 50K0.4L0.6
3. 若 α +β<1,則此生產為遞減的規模報酬;即產量增加的比例小於生產因素增加的比例。例: Q = 100K0.5L0.3
2010/05/18 28OPLAB
Definitions of Xi1(t) and Xi2(t)
Assuming m = 2 in our formulation of CDPS, the Cobb–Douglas utility function is expressed as Ui
(X1,X2) = X1c ·X2
d
– where c, d ≥ 0. Let X1 be any performance metric that the service provider wants to optimize, such as the average connection throughput or average delay. Let X2 be a fairness measure that increases as the connection’s or system’s perception of fairness increases, which results in an increase in U
2010/05/18 29OPLAB
Definitions of Xi1(t) and Xi2(t)
To maximize the system’s overall utility, we need to achieve the highest possible values of Xi1(t) and Xi2(t) for all connections.
However, it is not possible to achieve high values of both Xi1(t) and Xi2(t) for all connections because of the tradeoff between capacity and fairness
2010/05/18 30OPLAB
Definitions of Xi1(t) and Xi2(t)
Given these two definitions, the fairness measure for connection i at time t, αi(t) can be defined
Si(t) is the average throughput for connection i up to time t
maxj Sj(t) is the maximum average throughput achieved among all connections up to time t.
the fairness measure for connection i is the ratio of its average throughput to the maximum throughput achieved among all the connections in the system. We call this measure the “relative fairness.”
2010/05/18 31OPLAB
Definitions of Xi1(t) and Xi2(t)
The opportunity cost of serving connection i at time t (i.e., the opportunity cost of fairness) is defined as
where Ri(t) is the current data rate for connection i at time t, which depends on its channel condition,
maxj Rj(t) is the maximum current data rate of all connections at time t
2010/05/18 32OPLAB
Definitions of Xi1(t) and Xi2(t)
c: the Cobb–Douglas utility function’s constant, where c ≥ 0. The value of this constant determines the weight on Xi1(t) in the Cobb–Douglas utility function
d: the Cobb–Douglas utility function’s constant, where d ≥ 1. The value of this constant determines the weight on Xi2(t) in the Cobb–Douglas utility function.
We restrict the value of this constant to an odd integer because our defined Xi2(t) in the adopted Cobb–Douglas utility function is a negative function
d must be odd
2010/05/18 33OPLAB
Definitions of Xi1(t) and Xi2(t)
Xi1(t) = Ri(t): the current data rate of connection i at time t
The utility of connection i being served increases as Ri(t) increases. It should be noted that other performance metrics could be used. However, we use the current data rate as the first component in the Cobb–Douglas utility function to increase the system capacity and, hence, achieve the efficiency objective
2010/05/18 34OPLAB
Definitions of Xi1(t) and Xi2(t)
Xi2(t) = f(αi(t), γi(t)) = 1 − γi −ln(αi(t))
γi > 1: the fairness measure, which is a function of the relative fairness that we defined to increase fairness in the system
2010/05/18 35OPLAB
Definitions of Xi1(t) and Xi2(t)
The parameter γi is used to control the shape of Xi2(t) and , hence, the level of fairness in the system
γi can be set to different values for different connections to allow the service provider to maintain different levels of fairness for different connections depending on the type of traffic they have, the amount of money they are expected to pay, their loyalty, etc.
2010/05/18 36OPLAB
Definitions of Xi1(t) and Xi2(t)
Objective function
Connection Selection
2010/05/18 37OPLAB
Experiment Environment Setting
Simulation Model
2010/05/18 38OPLAB
Simulation Parameters
2010/05/18 39OPLAB
Test Environments
Case I: Ped A (Fig 5~12)– The mobile users in the Ped A environment move at a fi
xed speed of 3 km/h, which is the recommended value by the 3GPP
Case II: fixed differentiated channel conditions (Fig 13, 14)– The fixed channel environment is created to evaluate th
e performance of the CDPS under different fixed channel conditions (as opposed to Ped A in which the channel conditions of users vary with time, according to the models specified by the 3GPP)
2010/05/18 40OPLABFig. 5. Cell throughput. Fig. 6. Cell throughput with different values of K.
2010/05/18 41OPLAB
Fig. 7. Distribution of connection average throughputs.
2010/05/18 42OPLAB
Fig. 8. Distribution of connection average throughputs with different values of K.
2010/05/18 43OPLAB
Fig. 9. User satisfaction with minimum throughput of 128 Kbps
2010/05/18 44OPLAB
Fig. 10. User satisfaction with minimum throughput of 128 Kbps with different values of K.
2010/05/18 45OPLAB
Fig. 11. User satisfaction with minimum throughput of 356 Kbps
2010/05/18 46OPLAB
Fig. 12. User satisfaction with minimum throughput of 356 Kbps with different values of K.
2010/05/18 47OPLAB
Fixed Differentiated Channel Conditions
Seven values are used for the SNR: −7, −4, −1, 2, 5, 8, and 11 dB
For each SNR value, there are ten connections (a total of 70 connections in the cell)
2010/05/18 48OPLAB
Fig. 13. Average connection throughput for connections with different SNR values.
2010/05/18 49OPLAB
Fig. 14. Percentage of packet loss for connections with different SNR values.
2010/05/18 50OPLAB
Conclusions
we have proposed a CDPS scheme for future wireless cellular systems that is based on a utility function to represent the satisfactions of the mobile users as perceived by the service provider
Our scheme also utilizes an opportunity cost function to represent the satisfactions of the service provider
CDPS can simultaneously meet four design objectives, that is, efficiency, fairness, users’ satisfactions, and flexibility
2010/05/18 51OPLAB
Comments
How does it work on real-time traffic or another service types? – X1
c may be delay or delay jitter.
– Objective function have to be modified.
How is the uplink data flow? What is the business model for a operator to
get maximum revenues? Strategy?
Thank you
Recommended