The Future of Mobile Wireless Internet Access
Nelson Sollenberger AT&T nelson@research.att.com
Web Phones: The Next Big Thing?
Neopoint 1000 About $300, 6 ounces, versatile and slim, connects to a PC and has speech recognition.
PDQ Smart Thin Phone Ericsson R380 Motorola i1000 Phone Probably about Heading for Plus The new Perhaps from $200, 4.2 ounces, the European About $250, 5 Ericsson R380 $1000, about 10 also from market, 5 ounces, has a phone, which ounces, from Qualcomm but ounces phone and pager features Qualcomm, has a smaller and handles e-mail. wireless data combines a screen. functions phone with a Palm Pilot. New York Times, April 15, 1999. Web Phones: The Next Big Thing?
AT&T Wireless Services TDMA & Internet Packet Data CDPD Service
The Mitsubishi phone operates as a quad mode TDMA phone for voice services and provides access to Internet and data services over the CDPD network, a packet-based wireless IP network.
Wireless Data Terminal Evolution

Sierra PCMCIA CDPD Modem

Nokia 9110 3COM Palm VII

Nokia 3G vision

AT&T Wireless Services
AT&T serves over 12 million subscribers with advanced digital TDMA technology and some analog technology, and provides packet data service with CDPD technology
TDMA European GSM North American TDMA Japanese PDC CDMA North American CDMA over 200 million ~ 40 million ~ 50 million ~ 50 million
GSM MOU and UWCC TDMA industry groups announced cooperation on January 13, 2000 for common technology development, including EDGE for 3G high-speed data services

Wireless Standards

Wireless Technology Channel Bandwidth Voice bearers 6 to 12 kbps Peak data rates (kbps) Frame length (msec) Frequency reuse Voice bearers Per MHz / base Micro/Hierarchical cell support Number of subs as of 4Q99 GSM/GPRS/EDGE 200 KHz 8 / 16 9.6 / 144 / 4 / 12 to 1 / to 30 / 20 to 60 Good ~ 200 million IS-136 TDMA 30 KHz 3 / 6 9.7 / 21 to 3 / to 33 Good ~ 50 million IS-95 CDMA 1.25 MHz 6 to 20 14.4 to to 48 Poor ~ 50 million WCDMA 5 MHz Up to 100 Up to 1 Up to 60 Fair to Poor N.A.

Wireless Data Technology

Dedicated wireless packet data systems Ardis RAM Mobitex Wireless data access using cellular systems Early systems - circuit access, CDPD & I-mode GPRS - packet data on GSM Packet data on IS-95 CDMA 3rd generation systems EDGE (Enhanced Data rates for GSM Evolution) Packet data on WCDMA HDR (High Data Rates for CDMA2000 - IS-95) WAP (Wireless Application Part) Bluetooth - connecting nearby devices
Macrocellular Wireless Data Evolution

Wideband OFDM HDR

CDMA2000 EDGE WCDMA

data 384 k rate

64 k 9.6 k
PDC I-mode GSM IS-136 CDPD IS-2000 2005
Dedicated Wireless Packet Data Systems - used for e-mail & short messages
Created by IBM & Motorola in 80s 25 KHz channels FM modulation 4800 bps (2-level) 19.2 kbps (4-level) National US network operated by American Mobile
Created by Ericsson in 80s 12.5 KHz channels GMSK modulation 8 kbps National US network operated by BellSouth
Early Data Services on Cellular Systems
Voice-band modems over analog cellular end-to-end with a cellular inter-working function 9.6 kbps circuit & FAX access over GSM, IS-136, PDC & IS-95 using a single time-slot or code and an interworking functions to standard modems CDPD - Cellular Digital Packet Data I-Mode - 9.6 kbps packet data over PDC - Japanese Personal Digital Communications (cellular)
CDPD - Cellular Digital Packet Data
Proposed by IBM in KHz channels (compatible with AMPS) Shared base stations with cellular & an overlay network GMSK modulation at 19.2 kbps Supports TCP/IP connectivity Multi-mode CDPD/AMPS & CDPD/TDMA handsets & PCMCIA cards Service provided by AT&T, Bell Atlantic & others
I-Mode Packet Data Service
NTT DoCoMo introduced packet data using PDC timeslots in 1997 with 9.6 kbps peak rates NTT DoCoMo introduced I-Mode service in early 1999 Dual-mode PDC voice and packet data handsets Micro-browser and IP based 1000s of content providers
weather stocks sports horoscopes short message service,.
Over 5 million subscribers in 1st year of service

GSM Evolution

Circuit data - 9.6 kbps HSCD - 32 kbps circuit data GPRS - 144 kbps packet data 1/3 & 1/1 reuse frequency hopping EDGE - peak data rates of 384 kbps VoIP over EDGE

GPRS Airlink

General Packet Radio Service (GPRS) Same GMSK modulation as GSM 4 channel coding modes Packet-mode Flexible time slot allocation (1-8) Radio resources shared dynamically between speech and data services Independent uplink and downlink resource allocation (Uplink State Flag polls uplink)

Extends GPRS packet data with adaptive modulation/coding 8-PSK/GMSK at 271 ksps in 200 KHz RF channels supports 9.02 to 69.2 kbps per time slot Supports peak rates over 384 kbps Requires linear amplifiers with < 3 dB peak to average power ratio using linearized GMSK pulses Initial deployment with 2x 1 MHz using 1/3 reuse with EDGE Compact as a complementary data service
Adaptive Modulation & Link Performance of EDGE

Throughput - kbps

15 C/I dB 30 35

EDGE Development

R1999 supports best effort packet data
trials in 2001 commercialization in 2002
R2000 supports Voice over IP over EDGE
commercialization in 2003
Key features IP centric dual-mode IS-136 & EDGE terminals launching R99 with EDGE Compact in 1 MHz x2 of spectrum launching R2000 with ~ 2 MHz x2 of spectrum

WCDMA Packet Access

Dual mode scheme with adaptive mode selection based on packet-traffic characteristics Small infrequent packets appended to random access request
Random Access Request Small packet

Random access channel

Large or frequent packets transmitted on dedicated channel to maintain closed loop power control and assign dedicated code

Random Access Request

Dedicated channel

packet

Orthogonal Variable Spreading Factor (OVSF) codes.
c4,1 = (1,1,1,1) c2,1 = (1,1) c4,2 = (1,1,-1,-1) c1,1 = (1) c4,3 = (1,-1,1,-1) c2,2 = (1,-1) c4,4 = (1,-1,-1,1) SF = 1 SF = 2 SF = 4

CDMA2000 Wireless Data

1.25 MHz carriers up to 384 kbps integrated voice & data airlink multicode operation

IS-95 CDMA HDR

Based on separate carriers for voice and data Asymmetrical 1.25 MHz channels 1.22 MHz chip rates No soft-handoff No power control on downlink uplink power control, similar to CDMA2000 & max of about 150 kbps synchronized base stations modulation/coding/spreading adaptation reuse of 1

IS-95 CDMA HDR (contd)

32 kbps to 2.4 Mbps rates Typical peak rates of 250 to 500 kbps Spectral efficiency of 400 to 600 kbps/base/MHz Uplink request downlink mode 600 times per second 2-branch RX proposed for terminal TDMA with intelligent scheduling on downlink IP networking to the base station IP based mobility management voice or packet data access (not simultaneous - possible in the future with multi-carrier CDMA terminals)

4G Wireless

IP packet data centric A wireless cable modem Asymmetric access WOFDM downlinks (peak rates of 5 to 10 Mbps) 3G (EDGE) uplinks High-speed service to advanced handsets, laptops, PDAs, body-computers with heads-up displays, dash-board computers,. Complements 2G/3G Wireless Targets spectrum from 500 MHz to 3 GHz Flexible bandwidth - 200 KHz to 5 MHz Full macro-cell coverage Very high spectrum efficiency for downlink & uplink
OFDM/Multi-carrier Applications
Military HF modems Voice-band modems Digital Broadcasting ADSL WLANs (IEEE 802.11 & HiperLAN II) WDM fiber optics Cable modems

OFDM Characteristics

High peak-to-average power levels Preservation of orthogonality in severe multi-path Efficient FFT based receiver structures Enables efficient TX and RX diversity Adaptive antenna arrays without joint equalization Support for adaptive modulation by subcarrier Frequency diversity Robust against narrow-band interference Efficient for simulcasting Variable/dynamic bandwidth Used for highest speed applications Supports dynamic packet access

Smart Antennas

Switched Multibeam Antenna

SIGNAL

Adaptive Antenna Array

BEAMFORMER

BEAM SELECT
SIGNAL OUTPUT INTERFERENCE BEAMFORMER WEIGHTS

SIGNAL OUTPUT

INTERFERENCE
Smart Antennas significantly improve wireless system performance Interference suppression Quality and capacity improvement (2x capacity is practical) Multipath diversity Improve reliability Higher antenna gain Range extension and lower cost (50 to 100% greater coverage possible)
Network Based Dynamic Packet Assignment
2. Mobile sends measurements of path losses for nearby Bases to serving Base
4. Bases assign channels to all packets/mobiles to maximize throughput/QOS 1. Mobile locks to the STRONGEST Base 5. Bases forward channel assignment info to nearby Bases
3. Serving Base forwards measurements to nearby Bases
Wireless Application Protocol (WAP)
Mobile computing architecture supporting virtually all wireless network technologies Provides an inter-working function between a wireless client and a fixed server to mitigate low bandwidth and unreliable wireless access issues Uses Handheld Device Markup Language (HDML) and Wireless Markup Language (WML) Orientation to low-speed access

WAP Architecture

Web server

HTML WML WML

WAP Proxy Wireless Network WTA Server

Binary WML

HTML Filter
WAP - Wireless Application Protocol WTA - Wireless Telephony Application WML - Wireless Markup Language HTML - HyperText Markup Language

Bluetooth

(named after Harold Bluetooth, Danish King) Goal is low-cost & short range radio link to connect devices locally (ex. handset & laptop) Supports simultaneous isochronous voice and asynchronous data Global specification using the 2.4 GHz ISM band Conceived by Ericsson Founders are Ericsson, IBM, Intel, Nokia, Toshiba Over 800 companies have joined as Adopters Version 1 specification 2Q99 Chipsets available in 2000

Bluetooth Networking

Cordless corporate Ad Hoc LAN public

Internet

cellular

Bluetooth Air Interface

2.4 to 2.48 GHz operation 1600 frequency hops per second GFSK modulation at 1 Mbps Discriminator detection Coding rate 1, 2/3 (Hamming 15,10) and 1/3 (repetition) 0 dBm or up to 20 dBm TX power 0.1% BER max at -70 dBm RX Packet data and/or circuit voice operation 64 kbps CVSD voice coding Peak data rates of 721 kbps
Wireless Internet Milestones
80s - Ardis & RAM dedicated packet data networks 90s - CDPD and circuit data over GSM & CDMA 1999 - Imode in Japan 2000 - many GPRS deployments planned 2001- initial WCDMA & EDGE launches 2001 - HDR launches ? - 4G & WOFDM