1. Fundamentals of Cellular and Wireless Networks
Lecture ID: ET- IDA-113/114
, v09
Prof. W. Adi
Lecture-14
Wireless Data Network Standards
And „ Principles of Wireless Networks“ K. Pahlavan ch. 9
Textbook Rappaport Ed.2 Ch. 11

2. Recommended Books Main source for this lecture part is :
[1] Principles of Wireless Networks, Kaveh Pahlavan &
P. Krishnamurthy, Prentice Hall 2002
Course textbook:
[2] Wireless Communications, Theodor Rappaport,
2nd Edition, Pretice Hall, 2002

3. Wireless and Mobile Data Network
Mobile networks transporting data between mobile subscribers
example: CDPD, SMS, GPRS
- Wireless Local Area Networks:
Wireless networks transporting data in a computer network
example: Bluetooth, , HIPERLAN
Wireless Geolocation
Summary of geolocation techniques

4. Classification of Mobile Data Network
Frequency
Spectrum
Cellular Digital Packet Data
Shared with AMPS
Overlay on GSM spectrum

5. GPRS: General Packet Data Service
System Architecture
GR: GPRS Register
Two GPRS supporting Nodes GSN
GGSN: Gateway GPRS Supporting Node
SGSN: Serving GPRS Supporting Node
- Frequency Spectrum of GSM is used overlayed on the traffic channel of GSM

6. GPRS: General Packet Data Service Connection using two level tunneling
GGSN: Gateway GPRS Supporting Node
SGSN: Serving GPRS Supporting Node
Two level of connection or tunneling in GPRS
MS to SGSN
SGSN to GGSN

7. GPRS: General Packet Data Service
Specifications
GPRS Packets: short packets 500 – 1000 bytes
GPRS Speed
GRPS can theoretically use one to eight of the GSM timeslots for uplink
and downlink traffic
The capacity ranges from 9.05 kbps to 21.4 kbps where the slower ones
provide varying amounts of error correction
Note: In some articles you may read that GPRS will provide users with a bandwidth of kbps. This is the theoretical maximum speed (21.4 * 8 = kbps) and will hardly be achieved in a real network, since 8 timeslots will hardly be available at the same time.

8. GPRS Devices GPRS Devices
GPRS device are expected to be in many different kinds, shapes and functionality. However, all GPRS devices can be divided into three different categories:
Class A devices can operate GPRS simultaneously with other GSM
services (such as a normal voice call).
Class B devices can operate both GPRS and GSM services but not at
the same time. The device must shift between the two modes
but can be registered in the network for both.
Class C devices operate exclusively GPRS services
(although some devices may be manually set to handle GPRS or GSM, these are then seen as two different devices by the network, depending on the manual mode setting).

9. SMS: Short Messaging Service
Reference Architecture using GSM infrastructur Communicates up to 160 characters for each short message
(very popular and effective in Europe and all GSM systems)
SMSC: SMS Center
Each message is maintained and transmitted by the SMS Center SMSC
SMSC takes care of sorting and routing the messages
Message transmission over GSM network
Two main functions:
SMS- GMSC Gateway switching center, forwards short message to the terminal MS
SMS-IWMSC Interworking switching center. Forwards SMS from MS to the SMSC using a global identity to each message

10. SMS: Short Messaging Service
Air Interface Channels Used for Mobile Originated SMS
Channel abbreviations:
RACH Random Access Channel
SDCCH Standalone Dedicated Control Channel
AGCH Access Grant Channel

11. WAP: Wireless Application Protocol
Over mobile network
WAP is: Mobile user application infrastructure for advanced service carried on SMS, GPRS, CDPD connecting Internet to mobile user.
WAP protocol should help implementing a variety of applications that include Internet access, m-commerce, multimedia, , telemedicine, mobile positioning etc.

12. WAP: Wireless Application Protocol programming architecture
WAE: Wireless Application Environment

13. Wireless Data Networks And Home area networks
HAN: Home Area Network
Power Line Communication Network
HPAN: Home Phone Network Alliance
Wireless Communication

14. 1. Power Line Communication Network
Power Line Channel
Typical power line transfer function
Typical power line noise level

15. Power Line Communication bands
Frequency bands for low- and high-speed data transmission over power line
Data rates: more than 1 Mbps using spread spectrum technology

16. Possible Power Line Communication Scenario
The majority of home communication applications can be accommodated on a power line network

17. 2. HPNA: Home Phone Network Alliance
25kHz-1.1 MHz
20 Hz-3.4 kHz
2-30 MHz
HPNA frequency range
10 Mbps and more

18. HPNA: Home Application Example

19. 3. Wireless LANs: Wireless Local Area Networks
3.1 IEEE
3.2 Wireless ATM
3.3 HIPERLAN-1
3.4 HIPERLAN-2
4. Wireless Personal Area Network
4.1 Bluetooth

20. 3.1 Wireless Local Area Networks: IEEE 802.11 Reference Model
Infrastructure Network
Ad-hoc Network

21. 3.1 IEEE 802.11 Physical Layer FHSS version and its Frequency Band
26 channels for each group
Total is 26 x 3=78 channels
2.44 GHz
Hops over 78 channels of 1 MHz in the center of the 2.44 GHz ISM Band
Min hop rate 2.5 hops/sec, Max data rate on physical layer is 8.5 Mbps
Maximum recommended power is 100 mw
ISM Band: Industrial, Scientific and Medical band

22. 3.1 IEEE 802.11 Physical Layer DSSS Version and its Frequency Band
11 Overlapping frequency bands
Spaced by 5 MHz.
26 MHz
- Uses Barker Code sequence of length 11
Chip rate is 1 Mcps occupies about 26 MHz of bandwidth.
Max Data rate on physical layer is 25.5 Mbps

23. 3.2 Wireless ATM and HIPERLAN (Europe)
Vision of the ATM Forum’s Wireless ATM for an end-to-end ATM network

24. 3.2 Wireless ATM: WATM Frame format
Compatible to standard ATM packet

25. 3.3 HIPERLAN-1: High Performance Radio LAN
Requirement defined by ETSI (Europe):
Data Rate of Mbps
Coverage 100 meter
Multi-hop ad hoc networking
Support of power saving
use of 5GHz unlicensed band
Bridge common terminal

26. 3.4. HIPERLAN-2 Coordinating with IEEE 802.11 Infrastructure Ad hoc
Uses of 5GHz unlicensed band
Data rate up to 54 Mbps
Ad hoc

27. 3.4 HIPERLAN-2, OFDM Modem

28. 3.4 HIPERLAN-2 Frequency Bands

29. 4. Ad Hoc Networking and WPAN
Wireless Personal Area Network
Home RF system

30. 4.1 BLUETOOTH A short range wireless voice and data communication
Started by Ericsson, Nokia, IBM, Intel, Toshiba 1998
IEEE (1999)
Cable replacement
Ad hoc personal network
Unlicensed 2.4 GHz
1 Mbps
Interferes with !
Integrated access point
Application Scenarios

31. 4.1 BLUETOOTH Scattered ad hoc Topology Up to 10 piconets In one area
Slave
Master
Can handle up to
7 simultaneous
and 200 active slaves
Parked
Stand by
S can share two networks

32. Wireless Geolocation Systems

33. Wireless Geolocation Systems
Task: Find the location of the
terminal in the network
General architecture of a geolocation system

34. Location Aware Applications
Government Applications
Emergency calls (E911 requirement by FCC in US: location of emergency calls with the 67 % accuracy of 50m (MS based) or 100m (NW based) by Oct. 2001
Electronic surveillance
Operator Applications
Home zone calls
Traffic locating for network planning
Assistance for handover
Commercial Location Based Services
Fleet management, tracking packages
Info of the nearest hotel, gas station…
Car Navigation
Emergency roadside service
Search of stolen property, ... ?
Source: Ville Ruutu, NRC, “Network location services”

35. Technologies Suitable for Positioning of Cellular Phones
1. Cellular Network-Based Methods
2. Space-Based Radio Navigation Systems
3. WLAN and Short Range Connectivity Systems
4. Sensor Technology

36. 1. Cellular Network-Based Methods
Pure network-based methods
Bilateral (only one MS) methods:
Cell ID, Cell ID + Round Trip Delay (RTT), Location Fingerprinting (LF)
No active contribution from MS => no changes to MS
Inexpensive, fast to implement
Usually poor accuracy (< m)
Multilateral (multiple BSs measuring simultaneously) and unilateral (MS measures multiple BSs) methods:
Angle of Arrival (AOA), Time of Arrival (TOA), Time Difference of Arrival (TDOA), Rx-levels
Rather expensive, requires new signaling and network elements and synchronization
Moderate accuracy
MS-assisted network-based methods
MS has an active part in position measurement (unilateral), but position calculation is in the network-end
Enhanced Observed Time Difference (EOTD), Advanced Forward Link Trilateration (AFLT), Idle Period Downlink-Observed Time Difference of Arrival (IPDL-OTDOA)
Moderate accuracy (< m)
MS-based network-assisted methods
MS has an active part in position measurement and it calculates also its position
Otherwise the same as MS-assisted NW-based methods

37. Cell Identity (CI) Pure network-based bilateral method
The identity of the serving cell gives the location
The estimate can be e.g. the mass center of the coverage area
Only minor software changes in the network are required ==> Low cost method
The current accuracy is not enough for all applications
In GSM cell size varies typically 200m - 35 km
In the future this may provide an easy way to locate the mobile in some environments (micro and pico cells)
Cell ID
Source: Ville Ruutu, NRC, “Network location services”

38. CI + Timing Advance (TA) (1/2)
Pure network-based bilateral method
In GSM the time delay between the MS and the serving BTS, Timing Advance (TA), must be known to avoid overlapping time slots
TA gives the distance d, which defines a circle around the BTS:
d = (TA * c) / 2, where c is the speed of radio waves, and TA is in time units
TA information already available ==> Low cost method
Accuracy is not very good since the resolution of TA corresponds to 550 m
In GSM Standards only one TA circle (to serving cell) is used (together with serving cell coverage area) d
Source: Ville Ruutu, NRC, “Network location services”

39. CI + Timing Advance (2/2)
Independent TA based location would require at least 3 circles, i.e. the mobile should communicate with at least three base stations
This was not adopted in GSM standards
Source: Ville Ruutu, NRC, “Network location services”

40. CI+Round Trip Time (RTT)
Pure network-based method
In UMTS Round Trip Time (RTT) measurement is introduced
RTT is similar to TA in GSM
Accuracy should be much better than in GSM due to larger bandwidth
RTT
Source: Ville Ruutu, NRC, “Network location services”

41. Received Signal Levels (Rx-level)
Pure network based unilateral method
Received signal level depends on the distance between the mobile and the base station
Using propagation models the distance can be estimated ==> Distance defines a circle
Changing propagation conditions can cause problems
For example in GSM signals levels are already known in network
==> Low cost method
Source: Ville Ruutu, NRC, “Network location services”

42. Angle Of Arrival (AOA) Pure network-based multilateral method
Angle of arrival of the signal from the MS is measured in base station by directional antennas
At least 2 AOAs are needed
Coordination between base stations is required => This generates extra signaling load
No changes are necessarily needed in mobile station
Relatively accurate in good conditions, but reflections and Non Line Of Sight (NLOS) can be problems
Location error increases with distance between the MS and antennas
AOA requires HW (e.g. antennas) and also SW changes to base stations
=> Cost can be high
Source: Ville Ruutu, NRC, “Network location services”

43. Time Of Arrival (TOA) Pure network-based multilateral method
TOA of a signal from the mobile is measured at different places in the network
Difference in TOA values measured between two places determines a hyperbola:
c*(TOA1-TOA2) = d(MS,BTS1) - d(MS,BTS2),
where c is the speed of radio waves, and d denotes distance.
At least 2 hyperbolas are needed, but 3 hyperbolas for a unique solution
Relatively accurate, e.g. simulations in GSM show that 67 % accuracy is 200 m with 2 hyperbolas in urban and 100 m in suburban area
No changes in the mobile are required (in GSM)
TOA requires a common clock at measurement devices
TOA requires coordination between base stations
=> Extra signaling load is generated, and capacity is limited
TOA might require HW and SW changes to network
BTS3
BTS1
BTS2
Source: Ville Ruutu, NRC, “Network location services”

44. Enhanced Observed Time Difference (5)
GPS
Real time difference1,2
Real time difference2,3
Real time difference1,3
Clock drift2
Clock drift3
Clock drift1
LMU 2
LMU 1
LMU 3
Base station 2
SMLC
SMLC maintains assistance data and calculates MS positions
Base station 1
E-OTD (GSM)
IPDL-OTDOA (UMTS)
Cellular network based positioning methods require a synchronous network.
LMUs are used to measure base station clock drifts and real time differences.
Base station 3
(LMU): Location Measurement Unit
(SMLC): Serving Mobile Location Center

45. Idle-Period Down Link - Observed Time Difference Of Arrival (IPDL -OTDOA)
Similar to E-OTD
Originally proposed to 3GPP by Ericsson
OTDOAs are measured from pilot channel
Idle periods in down link transmissions from base stations are used to avoid "hearability" problem that is inherent in CDMA systems
Node B d1 d2
BTS
Idle Periods
Source: Ville Ruutu, NRC, “Network location services”

46. IPDL-OTDOA (2)
During an idle period, distant base stations become hearable
Idle periods
occur pseudorandomly
e.g. every 100 ms
have a period of 667 us (1 WCDMA slot)
IPDL is included in Release 99, and in R4 and R5 without essential changes
Similarities with GSM EOTD:
MS-assisted or MS-based unilateral method
ranging is based on TDOA
LMUs and SMLCs are needed for measuring real time differences and assisting UE

47. Some IPDL-OTDOA Simulation Results from Nokia
Source: Ville Ruutu, NRC, “Network location services”

48. Assisted-Global Positioning System (A-GPS)
Most Promising solution:
MS equipped with GPS, plus
other Network position used
GPS
Ephemeris, Almanac, Pseudoranges, etc.
Pseudoranges
Space Vehicle
Mobile Station with an integrated GPS
Base Station
GPS Antenna
Assistance Data from BS to MS
Location or
Measurements from MS to BS
GPS Signal
Cellular Signal
Cellular Signal (optional)

49. Recommended Books Main source for this lecture part is :
[1] Principles of Wireless Networks, Kaveh Pahlavan &
P. Krishnamurthy, Prentice Hall 2002
Course text book:
[2] Wireless Communications, Theodor Rappaport,
2nd Edition, Pretice Hall, 2002