Integration of Cellular Systems with
WLAN and Internet
Jack Winters
Chief Scientist, Motia, Inc.
Email: jwinters@motia.com
Phone: 732 208-5568
VTC2003 Fall
Slide 1
Wednessday, October 8, 2003
OUTLINE
 Current
Systems
 Current Trends
 Technical Issues
 Smart Antennas
 Predictions
VTC2003 Fall
Slide 2
Wednessday, October 8, 2003
Current Systems
Peak Data Rate
100 Mbps
High performance/price
UWB
3.1-10.6 GHz
802.11g/a
$/Cell
$/Sub
$ 500,000
$ 500
$ 1000
$ 100
$ 100
$ 10
2.4, 5.5GHz Unlicensed
10 Mbps
802.11b
2.4GHz Unlicensed
1 Mbps
BlueTooth
100 kbps
2.4GHz
High ubiquity and mobility
2G/3G Wireless
0.9, 2 GHz
10 feet
2 mph
VTC2003 Fall
100 feet
1 mile
10 mph
Slide 3
30 mph
10 miles Range
60 mph Mobile Speed
Wednessday, October 8, 2003
Current Trends
in WLANs
 Business
WLANs dominate, but home usage growing
faster (14 million WLANs sold last year)
 Spontaneous appearance of neighborhood/residential
access sites via consumer broadband wire-line
connections
 Public WLAN offerings for enterprise and home users
when they are away from the office or home
–
Players:




VTC2003 Fall
Wayport
Cometa (AT&T, Intel, IBM)
Aggregators: Boingo Wireless
Cellular companies (Verizon, AWS)
Slide 4
Wednessday, October 8, 2003
Internet Roaming

Seamless handoffs between WLAN and WAN
–
–

Cellular Wireless



high-performance when possible
ubiquity with reduced throughput
Management/brokering of consolidated WLAN and
WAN access
Adaptive or performance-aware applications
Nokia GPRS/802.11b PCMCIA card
NTT DoCoMo WLAN/WCDMA trial
Internet
Wireless LAN’s
Enterprise
VTC2003 Fall
Home
Public
Slide 5
Wednessday, October 8, 2003
Technical Issues
 Handoffs:
Many architectures proposed (see, e.g.,
Session 11C), currently in standards committees
 Voice/Music streaming/Video streaming in WLANs
(802.11e) (MERU)
 Range
 Higher data rates in both cellular and WLANs
 Capacity/Interference

VTC2003 Fall
Key constraint: Stay within existing standards/standard
evolution (enhance performance within standards and drive
standards evolution)
Slide 6
Wednessday, October 8, 2003
Wireless System Enhancements
Peak Data Rate
UWB
100 Mbps
3.1-10.6 GHz
High performance/price
802.11a/g
2.4, 5.5GHz Unlicensed
10 Mbps
802.11b
2.4GHz Unlicensed
1 Mbps
$/Cell
$/Sub
$ 500,000
$ 500
$ 1000
$ 100
$ 100
$ 10
Enhanced
BlueTooth
100 kbps
2.4GHz
High ubiquity and mobility
2G/3G Wireless
0.9, 2GHz
10 feet
2 mph
VTC2003 Fall
100 feet
1 mile
10 mph
30 mph
Slide 7
10 miles
60 mph
Range
Mobile Speed
Wednessday, October 8, 2003
Enhancements

Smart Antennas (keeping within standards):
–
–
–
–
–
VTC2003 Fall
Range increase
Interference suppression
Capacity increase
Data rate increase using multiple transmit/receive
antennas (MIMO)
Can be combined with radio resource
management techniques for even greater gains
Slide 8
Wednessday, October 8, 2003
Smart Antennas
SIGNAL
SIGNAL
OUTPUT
INTERFERENCE
INTERFERENCE
BEAMFORMER
WEIGHTS
Smart Antennas significantly improve performance:
• Higher antenna gain with multipath mitigation (gain of M with M-fold diversity) 
Range extension
• Interference suppression (suppress M-1 interferers)  Quality and capacity
improvement
• With smart antennas at Tx/Rx  MIMO capacity increase(M-fold)
VTC2003 Fall
Slide 9
Wednessday, October 8, 2003
Multiple-Input Multiple-Output (MIMO) Radio

With M transmit and M receive antennas, can provide M independent channels, to increase data
rate M-fold with no increase in total transmit power (with sufficient multipath) – only an increase
in DSP
–
–

Indoors – up to 150-fold increase in theory
Outdoors – 8-12-fold increase typical
Measurements (e.g., AT&T) show 4x data rate & capacity increase in all mobile &
indoor/outdoor environments (4 Tx and 4 Rx antennas)
–
–
–
VTC2003 Fall
216 Mbps 802.11a (4X 54 Mbps)
1.5 Mbps EDGE
19 Mbps WCDMA
Slide 10
Wednessday, October 8, 2003
Smart Antennas for Cellular
• Key enhancement technique to increase system capacity, extend coverage, and
improve user experience in cellular (IS-136)
SIGNAL
Uplink Adaptive Antenna
SIGNAL
OUTPUT
INTERFERENCE
BEAMFORMER
WEIGHTS
SIGNAL
In 1999, combining at TDMA base stations
changed from MRC to MMSE for capacity
increase
VTC2003 Fall
Slide 11
BEAMFORMER
Downlink Switched Beam Antenna
BEAM
SELECT
SIGNAL
OUTPUT
INTERFERENCE
Wednessday, October 8, 2003
Smart Antennas in
Cellular Systems
 Smart
antennas for WCDMA can provide
significant gains (>7 dB at handset)
–

VTC2003 Fall
But not justified today (Innovics, Metawave)
MIMO for WCDMA may be implemented in
2-5 years
Slide 12
Wednessday, October 8, 2003
Smart Antennas for WLANs
Smart
Antenna
AP
Smart
Antenna
AP
Interference
Smart Antennas can significantly improve the performance of WLANs
• TDD operation (only need smart antenna at access point or terminal for performance improvement
in both directions)
• Interference suppression  Improve system capacity and throughput
–
Supports aggressive frequency re-use for higher spectrum efficiency, robustness in the ISM band (microwave
ovens, outdoor lights)
• Higher antenna gain  Extend range (outdoor coverage)
• Multipath diversity gain  Improve reliability
• MIMO (multiple antennas at AP and laptop)  Increase data rates
VTC2003 Fall
Slide 13
Wednessday, October 8, 2003
“We don’t believe in dumb access points,”
says William Rossi, vice president and
general manager for Cisco’s wireless
business unit. “The access points will
eventually become smart antennas.”
Network World 06/02/03
VTC2003 Fall
Slide 14
Wednessday, October 8, 2003
When?
Communications Design Conference:
Craig Barratt (Atheros) - expects the technology (smart antennas) to
first appear before the end of next year in silicon for access points
supporting multiple antennas linking to single-antenna PC chip sets to
provide greater range or capacity - followed by support for multiple
antennas on both client and access-point chip sets. (Airgo - MIMO)
Craig Mathias (Farpoint Group) - expects to see cellphones with WiFi
emerge at the Consumer Electronics Show in January and to be in
production by June - we will see the logical convergence of cellular
and WiFi networks next year
Christian Kermarrec (Analog Devices) - you need standardization for
roaming to happen, and that won't come from the 3GPP until the end
of this year - it will probably not be implemented for another two or
three years
Andrew Seybold (Outlook 4Mobility) - seamless roaming between the
two networks won't arrive for as many as three years
VTC2003 Fall
Slide 15
Wednessday, October 8, 2003
Progression
Smart antennas for 802.11 APs/clients
 Cellphones, PDAs, laptops with integrated
WLAN/cellular
 Smart antennas for both WLANs and
cellular in these devices
 MIMO in WLANs (802.11n), with MIMO in
cellular (base stations)
 Seamless roaming with WLANs/cellular

VTC2003 Fall
Slide 16
Wednessday, October 8, 2003