all-ip 4g network architecture for efficient mobility and resource
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Transcript all-ip 4g network architecture for efficient mobility and resource
ALL-IP 4G NETWORK
ARCHITECTURE FOR EFFICIENT
MOBILITY AND RESOURCE
MANAGEMENT
Authors:
YOUNG-JUNE CHOI, UNIVERSITY OF MICHIGAN
KWANG BOK LEE AND SAEWOONG BAHK, SEOUL
NATIONAL UNIVERSITY
Source: IEEE Wireless Communications, 2007
老師: 連耀南 教授
學生: 邱淑怡 (97753506)
Outline
Introduction
Network architecture ALL-IP cellular network
Network architecture for efficient multiple
access
IP-triggered resource allocation
strategy(ITRAS)
IP QoS
QoS of wireless access networks
ITRAS
Conclusion
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Introduction – 4G
4G networks
4G networks have two different visions:
an all-IP based packet-switched system
similar to the IP backbone network
revolution— developing an innovative system
evolution — interworking with existing systems
This model covers a future scenario of
ubiquitous networking
Develop an innovative system with high
throughput and wide coverage
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Introduction - technique
The new techniques
orthogonal frequency division multiplexing (OFDM)
multiple input multiple output (MIMO) antennas
IEEE 802.16 standard sets a goal of WMAN
/WLAN based on OFDM or orthogonal
frequency division multiple access (OFDMA)
developed a hybrid multiple access scheme
combining OFDMA and frequency hopping
(FH)-OFDMA, where fast-moving users access
the network via FH-OFDMA
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簡述OFDMA/FH-OFDMA
OFDMA：個別或是一組tone可以分配給不同使
用者，多個用戶可以利用這種方式來分享頻寬，
可以和跳頻技術結合，以得到和CDMA相同的
好處
FH-OFDMA：在OFDMA系統的基礎上加入跳
頻的技術，以提高系統效能。依據預先確定的
跳頻序列，系統給各個使用者分配需要的頻率
It can overcome channel fading and multi-user
interference through an FH pattern
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FDM OFDM
Orthogonal Code:每個碼相加之後並不會干擾到另一
個正交碼
Frequency Division Multiplexing
OFDM frequency dividing
EARN IN SPECTRAL EFFICIENCY
6
TDMA/OFDM/OFDMA
Source : Orthotron Corp.
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Introduction
a new wireless network comprised
OFDMA microcells
FHOFDMA macrocells
Innovative 4G systems
medium access control (MAC) layer L1
physical (PHY) layer L2
Cover the network layer L3
8
Goal
Explain two models of all-IP cellular
network architecture
develop a subnet-based network that can
support L2 and L3 handoffs separately and
compare it with a pure all-IP network
Design a hierarchical cellular network that
consists of microcells and macrocells
Present a quality of service (QoS) support
methodology that tightly couples all three
layers
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Network architecture ALL-IP
cellular network
4G network has a simple structure where
each BS must function intelligently to
perform radio resource management as well
as physical transmission
BSaccess router (AR)
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Network architecture ALL-IP
cellular network
MT configures mobile IP (MIP) addresses for
handoff
takes several seconds to run the MIP handoff and
MIP hinders an MT from performing smooth
handoff
reducing the latency is still a challenging issue
Fast handoff scheme proposes to decrease the
address resolution delay by pre-configuration
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Network architecture subnet based
cellular network
separate the functionality of an AR from that
of an access point (AP) so that each
undertakes L3 and L2 protocols
AR manages several AP
BSC vs BS
A subnet includes
an AR and several AP
12
Compared two network architecture
Pure all-IP decentralized
Subnet-based all-IP centralized
pure all-IP network incurs L3 protocol in the
end access link, it requires long handoff latency
and high signaling overhead
13
Network architecture for efficient
multiple access
Cells
Macrocells are deployed in rural regions
Microcells are deployed in urban regions
Picocells are deployed in buildings
Designed a service model by mobility, such that
macrocells and microcells cover high speed and
low speed MT
hierarchical cell structure by integrating
multiple access techniques
Based on OFDMA
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Network architecture for efficient
multiple access
Cells handle traffic classes differently
High rate data services are suitable for OFDMA
Low rate data services(voice) are adequate for
FH-OFDMA
It’s difficult in supporting high data rates and AMC
(adaptive modulation and coding)
OFDMA microcells & FH-OFDMA macrocells
can support various users with different
mobility and traffic types
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Network architecture for efficient
multiple access
16
IP-triggered resource allocation
strategy(ITRAS)
IP QoS
QoS of wireless access networks
ITRAS
17
IP QoS
IETF recommends integrated services (IntServ)
and differentiated services (DiffServ) for IP QoS
IntServ: each router must implement
RSVP(Resource Reservation Protocol), IntServ
ensures strict QoS, cause difficulties in a large-scale
network
DiffServ: the packet is classified, each router can
mark, shape, or drop it according to network traffic
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QoS of wireless access networks
The importance of unified QoS management
grows in 4G networks as QoS management
for both access networks and IP networks
becomes cumbersome in all-IP networks
In ITRAS, L1 and L2 allocate radio resources
and logical channels, respectively, according
to the QoS indication of L3
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ITRAS
ITRAS concerns the information about IntServ
and DiffServ for the resource management of
L1 and L2
When IntServ establishes a real-time session, MAC
reserves a dedicated channel
when DiffServ is used for low mobility users, MAC
can exploit either a dedicated or a shared channel
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ITRAS
IP QoS information helps MAC and PHY
manage the following resources in a flexible
manner
Cell type – microcell or macrocell
Multiple access – OFDMA or FH-OFDMA
MAC channel – dedicated or shared
PHY scheduling – priority or fairness
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ITRAS
MT requests a real-time service in 4G, the
AR can initiate IntServ and allocate a
dedicated channel
For a downlink call, AR can adjust the
bandwidth of a dedicated channel with the
aid of RSVP
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ITRAS
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Conclusion
Discuss a new approach for designing an
architecture and QoS model in 4G
A subnet-based cell structure that consists of
AP and AR, each handling L2 and L3 handoffs.
Combine the multiple access schemes of
OFDMA and FH-OFDMA
mobile speed and traffic types
Design a unified QoS strategy, named ITRAS
IntServ and DiffServ can determine resource
attributes
24
Thanks for your attention