ECE 257A. Communication Networks

Transcription

1 ECE 257A. Communication Networks Lecture 01. Introduction and Overview Prof. Xinyu Zhang Department of Electrical and Computer Engineering University of California San Diego

2 Today s agenda Course logistics Why take this course? How to get an A? Modern work architecture 2

3 Course logistics

4 Administrative information Lecture schedule: 3:30pm-4:50pm, Tue. Thu. Instructor: Prof. Xinyu Zhang Instructor office hours: 4:50pm-6:20pm Tuesday, Thursday; Atkinson Hall 4314 OR: appointment TA: N/A Course website: More about me research themes Wireless systems and working Mobile and ubiquitous computing 4

5 Research in wireless systems and working Ubiquitous Gbps wireless working through mmwave radio beams Eliminating wireless interferences through distributed antennas High performance mobile applications 5

6 Research in mobile and ubiquitous computing 3D localization for smartphones and IoT e.g., LiTell Sensing human interaction with batteryless things e.g., Tagyro Sensing human interaction with small mobile devices e.g., UbiK, Okuli * See Youtube demos via Google: Xinyu Zhang 6

7 Research in mobile and ubiquitous computing Security for IoT e.g., Vibrometry, LiShield * See Youtube demos via Google: Xinyu Zhang 7

8 Why take this course?

9 What is this course about? All about communication works What are there? How do they work? Why do they work that way? Some new features Interdisciplinary: communication engineering + work system design Bridging systems with theory 9

10 What is this course about? (longer version) Network architecture: Building blocks of the modern wireless Inter Work flow of end-to-end data delivery Packet and signal processing at the lower layer Modulation, demodulation, packetization Multi-antenna technologies Channel models and fundamental capacity theorems Network protocols and operations at the higher layer MAC layer protocols and stochastic models Routing protocols and optimization models TCP and its optimization models 10

11 Learning objectives Understand the big pictures Understand the end-to-end work flows Acquire fundamental modeling skills Prepare for future study, research, and career 11

12 Learning objectives (longer version) Understand the big pictures Describe the modern wireless Inter architectures and workflows so that a person with general engineering background can understand Understand the fundamental modules in modern wireless technologies Being able to express the packet/symbol level processing in simplified models, and to implement the algorithms Understand the asymptotic capacity scaling mechanisms for wireless communication technologies 12

13 Learning objectives (longer version) Learn the performance modeling techniques for work protocols Stochastic models for MAC Optimization models and algorithmic aspects of routing and TCP Prepare yourself for future Research skills: surf the reference sea; writing and presenting reports Background knowledge for courses, e.g, ECE158B, ECE257B Research in working, wireless communications, and mobile computing Jobs in IT companies 13

14 How to get an A?

15 Prerequisite Basic understanding of computer works Low level course in communication systems 15

16 Elements of the course Homework assignment (20%) Course project (35%): Proposal: 5%, Final Report: 25%, Final presentation: 5% Final exam (40%) Course participation (5%) 16

17 Homework assignments 4 assignments, each involving 4-6 problems. Typical problems: Q&A, algorithms, modeling, simulation, and small programming assignments Certain assignments allow group work 17

18 Course project: 3 options System measurement and design Measurement and analysis of protocol/application behavior Design and validation of new work algorithms/protocols Theoretical modeling Modeling and performance evaluation of emerging protocols/applications, e.g., data center congestion control, millimeter-wave working, Topic survey Pick a specific topic and write a 10-page survey paper, e.g., softwaredefined mobile works, backscatter communications, IoT working, works for smart-grid, etc. 18

19 Course project Group projects are strongly recommended Up to 3 people are allowed for the first 2 options; up to 2 people are allowed for the area survey option Must get instructor approval if you want to work alone Project proposal due by 10/12/2017; Guidelines for project proposal will be provided through a separate A list of suggested topics will be provided by next Monday Final presentation: week 11/27 and 12/04. 19

20 Final exam Date: 12/08/2017 (tentative) If you are familiar with the lecture content and homework, you ll do well. Learning and reviewing course materials No textbook (mostly outdated). But reference papers and book chapters will be provided Polish your reference reading capability (only read the parts that are relevant to lectures) 20

21 Course participation Attend lectures regularly (let instructor know you) Participate in discussion Don t be afraid to ask layman questions Look at problems from different perspectives; use your domain knowledge Innovations often come from simple insights 21

22 Today s lecture: Modern Network Architecture

23 Evolution of modern Inter Inter connects human being s, online forums, social works Inter connects mobile computing devices Smartphones, wearable devices, gaming devices, Inter connects sensors and things Smart meters, smart furniture, smart appliances, Always-connected, context aware computing and communication 23

24 Modern Inter topology: simplified view Residential : o DSL, cable, fiber o Wireless (e.g., WiFi) ISP Backbone ISP ISP Data centers Campus/enterprise : o Ether o Wireless (e.g., WiFi) 24

25 Modern Inter topology: Network of Networks End systems connect to Inter via ISPs (Inter Service Providers) Residential, company and university ISPs Access ISPs in turn must be interconnected So that any two hosts can send packets to each other Resulting work of works is very complex Evolution was driven by economics and national policies 25

26 Modern Inter topology: Network of Networks Question: given millions of ISPs, how to connect them together? 26

27 Modern Inter topology: Network of Networks Option: connect each ISP to every other ISP? connecting each ISP to each other directly doesn t scale: ~N 2 connections. 27

28 Modern Inter topology: Network of Networks Option: connect each ISP to a global transit ISP? Customer and provider ISPs have economic agreement. global ISP 28

29 Modern Inter topology: Network of Networks But if one global ISP is viable business, there will be competitors. ISP A ISP B ISP C 29

30 Modern Inter topology: Network of Networks But if one global ISP is viable business, there will be competitors. which must be interconnected Inter exchange point ISP A IXP IXP ISP B ISP C peering link 30

31 Modern Inter topology: Network of Networks and regional works may arise to connect s to ISPs ISP A IXP IXP ISP B ISP C regional 31

32 Modern Inter topology: Network of Networks and content provider works (e.g., Google, Microsoft, Akamai ) may run their own work, to bring services, content close to end users ISP A IXP Content provider work IXP ISP B ISP B regional 32

33 Modern Inter topology: Network of Networks Tier 1 ISP Tier 1 ISP Google IXP IXP IXP Regional ISP Regional ISP ISP ISP ISP ISP ISP ISP ISP ISP at center: small # of well-connected large works tier-1 commercial ISPs (e.g., Sprint, AT&T), national & international coverage content provider work (e.g, Google): private work that connects it data centers to Inter, often bypassing tier-1, regional ISPs 33

34 Access work: the last-hop, the bottleneck Enterprise work (companies, organizations, campus) institutional link to ISP (Inter) institutional router Ether switch institutional mail, web servers typically used in companies, universities, etc 10 Mbps, 100Mbps, 1Gbps, 10Gbps transmission rates today, end systems typically connect into Ether switch 34

35 Access work: the last-hop, the bottleneck Home work wireless devices sometimes combined in single box to/from headend or central office cable or DSL modem wireless point router wired Ether 35

36 Access work: the last-hop, the bottleneck 4G cellular mobile broadband (simplified view) MAC, PHY Radio work Core work (Evolved Packet Core, or EPC) Managed by cellular operators Inter Mobility, Security 36

37 4G LTE: architectural details Pre R8 2G/3G BTS/NodeB BSC/RNC SGSN PCRF R8 2G BTS BSC 2G SGSN Inter R8 3G NodeB RNC SGW PGW Operator services SGSN HSS LTE enodeb MSC Control plane User plane MME Basic architecture defined in 3GPP TS

38 Cellular mobile broadband: 4G LTE Elements Acronym Full name Function E-NodeB MME Mobility Management Entity Air interface toward 4G mobile users Mobility Management for 4G Control Plane only S-GW Serving Gateway Mobility Management for 4G User Plane, Handover anchoring. P-GW Packet Data Network Gateway Routing to Packet Data Network, Session Management, IP address Allocation. HSS Home Subscriber Server Manage Permanent 4G subscriber data. 38

39 Cellular mobile broadband: 4G LTE User plane vs. control plane User plane: user traffic that contains the conversation between 2 or more user peers Carried over the core work as a bearer, or flow User s voice call or data traffic Control plane: signaling communication used to control the bearer traffic. Involving sending and receiving messages between 2 nodes e.g., communication between MME and HSS 39

40 Cellular mobile broadband: 4G LTE A simplified packet switched call flow in LTE MS Attach request.. 1 enodeb Herewith the info 2 3 Get info for this subscriber HSS DNS Herewith the IP Addresses What is the S-GW IP Address? What is the P-GW IP Address? 5 4 Reference : TS TS TS I am attached to the work and want to browse MME Create Session Request with IP Address of S-GW and P- GW 6 Packet Data Network e..g Inter 11 Create Session Request response (Accept) 10 S-GW P-GW 8 Create Session Request response (Accept) 9 Create Session Request with IP Address of P-GW 7 Create Session Request response (Accept) 40

41 Cellular mobile broadband: 4G LTE A simplified packet switched call flow in LTE (Cont d) MS enodeb HSS DNS Reference : TS TS TS I am attached to the work and want to browse MME S-GW P-GW Packet Data Network e..g Inter Inter DNS 13 41

42 References Section of Computer working : a top-down approach, James F. Kurose, Keith W. Ross. The LTE Network Architecture - A comprehensive tutorial, Alcatel Lucent whitepaper, available at: S/LTE_Alcatel_White_Paper.pdf 42