1. Spectral Allocation

3. Evolution of Current Systems
Wireless systems today
2G + 2.5G Cellular: ~30-70 Kb/s.
WLANs: ~10 Mb/s.
Next Generation
2.75G + 3G Cellular: ~300 Kb/s.
WLANs: ~70 Mb/s.
Technology Enhancements
Hardware: Better batteries. Better circuits/processors. Co-optimization with transmission schemes.
Link: Antennas, modulation, coding, adaptivity, DSP, BW.
Network: Dynamic resource allocation, Mobility support.

4. 2.5G – Upgrade options GSM IS-95
High Speed Circuit Switched Data (HSCSD)
General Packet Radio Service (GPRS)
Enhanced Data rate for GSM Evolution (EDGE)
IS-95
IS-95A provides data rates up to 14.4 kbps
IS-95B provides rates up to 64 kbps (2.5G)

5. 3G Vision Universal global roaming Multimedia (voice, data & video)
Increased data rates
384 kbps while moving
2 Mbps when stationary at specific locations
Increased capacity (more spectrally efficient)
IP architecture
Problems
No killer application for wireless data as yet
Vendor-driven

6. Migration To 3G

8. CDMA2000 Pros and Cons Evolution from original Qualcomm CDMA
Now known as cdmaOne or IS-95
Better migration story from 2G to 3G
cdmaOne operators don’t need additional spectrum
1xEVD0 promises higher data rates than UMTS, i.e. W-CDMA
Better spectral efficiency than W-CDMA(?)
Arguable (and argued!)
CDMA2000 core network less mature
cdmaOne interfaces were vendor-specific
Hopefully CDMA2000 vendors will comply w/ 3GPP2

9. W-CDMA (UMTS) Pros and Cons
Wideband CDMA
Standard for Universal Mobile Telephone Service (UMTS)
Committed standard for Europe and likely migration path for other GSM operators
Leverages GSM’s dominant position
Requires substantial new spectrum
5 MHz each way (symmetric)
Legally mandated in Europe and elsewhere
Sales of new spectrum completed in Europe
At prices that now seem exorbitant

10. TD-SCDMA Time division duplex (TDD) Chinese development
Will be deployed in China
Good match for asymmetrical traffic!
Single spectral band (1.6 MHz) possible
Costs relatively low
Handset smaller and may cost less
Power consumption lower
TDD has the highest spectrum efficiency
Power amplifiers must be very linear
Relatively hard to meet specifications

11. Current Wireless Systems
Cellular Systems
Wireless LANs (802.11a/b/g, Wi-Fi)
Satellite Systems
Paging Systems
Bluetooth
Ultrawideband radios (UWB)
Zigbee/ radios
WiMAX (802.16)

12. Wireless Local Area Networks (WLANs)
Internet
Access
Point
0101
1011
WLANs connect “local” computers (~100 m range)
Breaks data into packets
Channel access is shared (random access)
Backbone Internet provides best-effort service
Poor performance in some app’s (e.g. video)

13. Wireless LAN Standards (Wi-Fi)
In future
all WLAN
cards will
have all 3
standards...
802.11b (Current Generation)
Standard for 2.4GHz ISM band (bw 80 MHz)
Frequency hopped spread spectrum
Mbps, 500 ft range
802.11a (Emerging Generation)
Standard for 5GHz NII band (bw 300 MHz)
OFDM with time division
20-70 Mbps, variable range
Similar to HiperLAN in Europe
802.11g (New Standard)
Standard in both 2.4 GHz and 5 GHz bands
OFDM (multicarrier modulation)
Speeds up to 54 Mbps

14. HIPERLAN • Types 1-4 for different user types
- Frequency bands: GHz, GHz
• Type 1
GHz band
- 23 Mbps, 20 MHz Channels
- 150 foot range (local access only)
- Protocol support similar to
- Peer to peer architecture
- ALOHA channel access
• Types 2-3
- Wireless ATM
- Local access and wide area services
- Standard under development
- Two components: access and
mobility support
8C a-Cimini-7/98

15. Satellite Systems Cover very large areas Different orbit heights
GEOs (39000 Km) via MEOs to LEOs (2000 Km)
Trade-off between coverage, rate, and power budget!
Optimized for one-way transmission:
Radio (e.g. DAB) and movie (SatTV) broadcasting
Most two-way systems struggling or bankrupt...
(Too) expensive alternative to terrestrial systems
(But: a few ambitious systems on the horizon)

16. Satellite networks: GEO
Japan
Singapore
GEO
Gateway
Gateway
Control
station
Control
station
Public
networks
Public
networks

17. Satellite networks: LEO
Japan
Singapore
LEO
LEO
Inter-satellite link
Gateway
Gateway
Control
station
Control
station
Public
networks
Public
networks

18. Paging Systems Simplex Limited to worldwide coverage possible
Broadcast / simulcast
Reliable  large Txd. Power, Low data rate
PSTN
Paging
Control
center
towers

19. Other Wireless Systems
Cordless telephone systems
Dedicated Base Station
Limited coverage
No handoff support
PSTN
Fixed
Base
Station

20. A general WLL setup

21. Bluetooth
A new global standard for data and voice Cable replacement RF technology
• Short range (10 meters)
• 2.4 GHz band
• 1 Data (700 Kbps) and 3 Voice channels
• Supported by over 200 telecommunications and
computer companies
Goodbye Cables !

22. Ultimate Headset

23. Cordless Computer

24. Automatic Synchronization
In the Office
At Home

25. Bluetooth Specifications
Connection Type
Spread Spectrum (Frequency Hopping)
MAC Scheme
FH-CDMA
Spectrum
2.4 GHz ISM
Modulation
Gaussian Frequency Shift Keying
Transmission Power
1 mw – 100 mw
Aggregate Data Rate
1 Mbps
Range
30 ft
Supported Stations
8 devices
Voice Channels 3
Data Security- Authentication Key
128 bit key
Data Security-Encryption Key
8-128 bits (configurable)

26. UltraWideband Radio (UWB)
Impulse radio: sends pulses of tens of picoseconds (10-12) to nanoseconds (10-9) - duty cycle of only a fraction of a percent
Uses a lot of bandwidth (order of GHz)
Low probability of detection by others + beneficial interference properties: low transmit power (density) spread over wide bandwidth
This also results in short range.
But : Excellent positioning (ranging) capability + potential of high data rates
Multipath highly resolvable: both good and bad
Can use e.g. OFDM or equalization to get around multipath problem.

27. Why is UWB interesting? Unique Location and Positioning properties
1 cm accuracy possible
Low Power CMOS transmitters
100 times lower than Bluetooth for same range/data rate
Very high data rates possible (although low spectral efficiency) Mbps at ~10 feet range under current regulations
7.5 Ghz of “free spectrum” in the U.S.
FCC (Federal Communications Commission) recently legalized UWB for commercial use in the US
Spectrum allocation overlays existing users, but allowed power level is very low, to minimize interference
“Moore’s Law Radio”
Data rate scales with the shorter pulse widths made possible with ever faster CMOS circuits

28. IEEE /ZigBee radios
Low-Rate WPAN (Wireless Personal Area Network) - for communications < 30 meters.
Data rates of 20, 40, 250 kbps
Star topology or peer-to-peer operation, up to 255 devices/nodes per network
Support for low-latency devices
CSMA-CA (carrier sense multiple access with collision avoidance) channel access
Very low power consumption: targets sensor networks (battery-driven nodes, lifetime maximization)
Frequency of operation in ISM bands

29. WiMAX: Worldwide Interoperability for Microwave Access
Standards-based (PHY layer: IEEE Wireless MAN family/ETSI HiperMAN) technology, enabling delivery of ”last mile” (outdoor) wireless broadband access, as an alternative to cable and DSL (MAN = Metropolitan Area Network). Several bands possible.
OFDM-based adaptive modulation, 256 subchannels. TDM(A)-based. Antenna diversity/MIMO capability. Advanced coding + HARQ.
Fixed, nomadic, portable, and mobile wireless broadband connectivity without the need for direct line-of-sight (LOS) to base station.
In a typical cell radius deployment of 3 to 10 kms, expected to deliver capacities of up to 40 Mbps per channel, for fixed and portable access.
Mobile network deployments are expected to provide up to 15 Mbps of capacity within a typical cell radius deployment of up to 3 kms.
WiMAX technology already has been incorporated in some notebook computers and PDAs. Potentially important part of 4G?

30. Data rate 10 kbits/sec 100 kbits/sec 1 Mbit/sec 10 Mbit/sec
0 GHz
2 GHz
1GHz
3 GHz
5 GHz
4 GHz
6 GHz
802.11a
UWB
ZigBee
Bluetooth
802.11b
802.11g 3G
Frequencies occupied

31. Range 1 m 10 m 100 m 1 km 10 km 0 GHz 2 GHz 1GHz 3 GHz 5 GHz 4 GHz
UWB
ZigBee
Bluetooth
802.11b,g 3G

32. Power Dissipation 1 mW 10 mW 100 mW 1 W 10 W 0 GHz 2 GHz 1GHz 3 GHz
UWB
ZigBee
Bluetooth
802.11bg 3G

33. Emerging Systems Ad hoc wireless networks Sensor networks
Distributed control networks

34. Ad-Hoc Networks Peer-to-peer communications.
No backbone infrastructure (no base stations).
i.e. “Truly wireless”!
Routing can be multihop.
Topology is dynamic in time; networks self-organize.
No centralized cooordination.
Fully connected, even with different link SINRs (signal-to-interference plus noise ratios)
-No backbone: nodes must self-configure into a network.
-In principle all nodes can communicate with all other nodes, but multihop routing can reduce the interference associated with direct transmission.
-Topology dynamic since nodes move around and link characteristics change.
-Applications: appliances and entertainment units in the home, community networks that bypass the Internet. Military networks for robust flexible easily-deployed network (every soldier is a node).

35. Sensor Networks Energy is the driving constraint
Nodes typically powered by nonrechargeable batteries.
Data (sensor measurements) flow to one centralized location (sink node, data fusion center).
Low per-node rates - but up to 100,000 nodes.
Sensor data highly correlated in time and space.
Nodes can cooperate in transmission, reception, compression, and signal processing.

36. Energy-Constrained Nodes
Each node can only send a finite number of bits.
Transmit energy minimized by maximizing bit time
Circuit energy consumption increases with bit time
Introduces a delay versus energy tradeoff for each bit!
Short-range networks must consider transmit, circuit, and processing energy - jointly.
Most sophisticated transmission techniques not necessarily most energy-efficient!
Sleep modes save energy - but complicate networking.
Changes everything about the network design:
Bit allocation must be optimized across all protocols.
Delay vs. throughput vs. node/network lifetime tradeoffs.
Optimization of node cooperation.
All the sophisticated high-performance communication techniques developed since WW2 may need to be thrown out the window.
By cooperating, nodes can save energy