Next Generation Next G Wireless Networks 722004 Farid

Next Generation (Next. G) Wireless Networks 7/2/2004 Farid Farahmand

Outline n n Description of wireless networks Wireless network evolution Wireless key technologies Current researches

Wireless Networks n Motivated by people-on-the-go ¡ n n PCs availability, Internet usage, Mobile life Aimed is to establish wide-area voice data communications Includes mobile systems (cellular telecommunication systems)

Wireless Network Evolution n First generation (1 G): Analog voice systems ¡ n Second Generation (2 G): Digital voice systems ¡ ¡ ¡ n No standardization Currently deployed systems CDMA, GSM (Global System for Mobile communication), PDC (Japan) D-AMPS (Digital Advanced Mobile Phone System) PCS Systems Second Generation – advanced (2. 5 G): Combining voice and data communications ¡ ¡ Providing enhanced data rate Two basic technologies: n n GSM-based (high baud rate) GPRS (General Packet Radio Service) ¡ ¡ Utilizes voice time slots to send packet traffic An overlay over the existing voice system Should really be called 2. 1 G!! Any standards?

Wireless Network Evolution n Third Generation (3 G): Digital voice and data communications ¡ Developing a more general mobile network n n ¡ n Handling Internet access, email, messaging, multimedia Access to any services (voice, video, data, etc. ) Requires high quality transmission Forth Generation (4 G): All-IP mobile networks ¡ ¡ ¡ Ubiquitous wireless communications Transparent to any services Integrating multinetworks

Third Generation (3 G) n Two basic proposals to handle voice and data ¡ Ericsson: Universal Mobile Telecommunications systems (UMTS) n n ¡ Qualcom: CDM 2000 n n n Not compatible with GSM (cannot hand off called to GSM-based cells) Compatible for IS-95 (supported by U. S) 3 G Standards ¡ ¡ n Compatible with European GSM Backed by ETSI and Japan 1999 UMTS took over and an agreement was made over setting some standards A revolutionary technology with unlimited potential or not so great? Major competing technologies ¡ ¡ Bluethood Wireless LAN (IEEE 802. x standards) – also known as Wi. Fi n n n Short range wireless communications Highly utilized and very popular: offices, airports, coffee shops, universities and schools Two basic modes of operations: ¡ ¡ Ad-hoc networking: computers send data to one another Access point: : sending data to the base station

Forth Generation Wireless Networks n n n Otherwise known as Next. G, Beyond 3 G, 4 G, and more! Motivation ¡ Providing all available services to highly mobile people (anytime anywhere) ¡ Use your wireless device anywhere for listening to music, shopping (m-commerce) , downloading (file transfer), watching video (live streaming) ¡ Multiple applications (talk and use Internet services at the same time) Objectives ¡ Total convergence of the wireless mobile and wireless access communications (developing a broadband wireless network) ¡ Ubiquitous wireless communications and services n Integration of multi-networks using IP technology n Similar technology to the wired Internet where users are freed from their local networks ¡ All-IP based wireless networks n Not just IP end-to-end but over-the-air packet switching n Supporting native wireless IP mode n Highly integrated n High bandwidth / high-speed wireless ¡ Highly compatible with wired network infrastructures n ATM, IP, ATM

4 G Technology Challenges n Supporting heterogeneous multitude of systems ¡ Includes multiple networks: n n ¡ ¡ n Open communication network: infrastructure independent which can access to any services and applications (now and in the future!) Complete compatibility between wireless and wired networks through gateways Supporting statistical multiplexing of heterogeneous data over-the-air ¡ n Cellular telecommunication systems Digital video broadband Digital audio broadband Wireless LAB, Bluethood-based networks Latency, noisy environment, unpredictable discontinuities and loss, etc. High-speed wireless transmission over the air ¡ High performance physical layer n ¡ 20 Mbps (2 G: 28 Kbps, 3 G: 2 Mbps) Scarce bandwidth availability n n Efficient frequency spectrum utilization Efficient hand off Dynamic bandwidth allocation Advanced digital transmission technology (modulation, low power devices, etc. )

4 G Key Issues - Research Areas n IP Addressing ¡ n Architecture ¡ ¡ n Horizontal communications between different access technologies using gateways Including local-area access technology (3 G only covers wide-area packet switched cellular technology) Hand off ¡ ¡ n Mobile IPv 6 protocol provides unbroken connectivity between mobile nodes Fast hand off due to high-speed transmission High reliability Qo. S framework ¡ ¡ Interoperability between wireless and wired networks Qo. S classes: Conversational (most delay sensitive), streaming, interactive, background (least delay sensitive) Fair bandwidth allocation Class-based Qo. S over the air

4 G Key Issues - Research Areas n Security and billing ¡ ¡ ¡ Essential in e-commerce More than just authentication and encryption (as in 3 G) End-to-end security mechanisms between the Internet server (wired) and the mobile terminal n n Usage fee ¡ n No translation and decomposition of the data at the gateways Volume based or time-based? TCP performance in wireless / mobile communications ¡ ¡ Research shows unmodified standard TCP is not well aligned with cellular boundaries New protocols have been developed: Snoop, Split connections, other end-to-end protocol families n n Using Snoop agent the exchange of TCP packets and ACKs are monitored and performs local retransmissions as needed (OBS-like!) Split-connections deals with wireless and wired network inconsistencies (gateways, translations, etc. ) ¡ n Two separate connections between fixed and mobile hosts End-to-end protocols deal with retransmission timeout causing the TCP window to shrink too often

Qo. S-enabled MAC Protocol. Scheduling Problem n Mac protocols: ¡ ¡ n Voice-based MAC protocols don’t work well for multimedia applications ¡ n n n Wirelines: FIFO, Generalized Processor Sharing (GPS) Wireless: Random Access Protocols No packet ordering is supported, no fair packet loss sharing Multimedia traffic exhibit highly bursty traffic rates Each class of traffic has a Qo. S requirement and traffic rate characteristics A new MAC protocol with fair packet loss sharing scheduling for 4 G is proposed ¡ ¡ Assumes time-division/code-division multiple access wireless system with IP transmission Objective (conflicting): n n ¡ Basic Idea: n n ¡ support as many users as possible (high channel utilization), dropped packets between all users are shared fairly Allocate minimum amount of resources to satisfy the Qo. S requirements Maximize the total number of scheduled packets How to calculate the number of packets dropped: n n Give enough BW to meet the Qo. S guaranteed level, drop the rest Maximize the number of packets sent: bin-packing problem Blocks IP Pkts Pack Bins Time Slots

Class-based Qo. S over Air Interface in 4 G n Basic characteristics: ¡ ¡ n Basic Idea: ¡ ¡ ¡ n n Flexible (support various services) Effective (easy negotiation mechanism to handle Qo. S over air) Check congestion over the air When congestion occurs, users with lower Qo. S have to back off their transmission rate The extent of the back off depends on the class it belongs to Basic problem is possible under-utilization Supports any number of Qo. S classes based on the specified resource assignment for each class Qo. S Over Air Wireless Internet Bkbone