1. 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)

2. 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 2

3. Introduction – 4G  4G networks  an all-IP based packet-switched system  similar to the IP backbone network  4G networks have two different visions:  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 3

4. 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 4

5. 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 5

6. 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

7. TDMA/OFDM/OFDMA 7 Source : Orthotron Corp.

8. 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

9. 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 9

10. 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  BS  access router (AR) 10

11. 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 11

12. 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

13. 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

14. 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 14

15. 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 15

16. Network architecture for efficient multiple access 16

17. IP-triggered resource allocation strategy(ITRAS)  IP QoS  QoS of wireless access networks  ITRAS 17

18. 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 18

19. 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 19

20. 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 20

21. 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 21

22. 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 22

23. ITRAS 23

24. 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

25. Thanks for your attention