1. Anders Västberg vastberg@kth.se 08-790 44 55
Wireless Systems IK1330
Anders Västberg

2. IK1330 Wireless Systems TEN1: 4,5 hec. LAB1: 3 hec. Required reading:
A part theory, B part problems
LAB1: 3 hec.
Three labs, propagation and planning, WLAN, measurements,
Required reading:
Stallings, W., Wireless Communications and Network, Pearson, 2005
Course Webpage:
Book Webpage:

3. Stallings: Wireless Communications and Networks

4. Radio Communication
Radio or radio communication means any transmission, emission, or reception of signs, signals, writing, images, sounds or intelligence of any nature by means of electromagnetic waves of frequencies lower than three thousand gigacycles per second (3000 GHz) propagated in space without artificial guide.
Examples of radio communication systems:
Radio broadcasting.
TV broadcasting.
Satellite communication.
Mobile Cellular Telephony.
Wireless LAN.
Multimedia communication & Mobile Internet
[Slimane]

5. History 1864: Maxwell describes radio wave mathematically
1888: Hertz generates radio waves
1890: Detection of radio waves
1896: Marconi makes the first radio transmission
1915: Radio tubes are invented
1948: Shannon’s law
1948: Transistor
1960: Communication Satellites
1981: Cellular technology

6. Classification of radio spectrum
Application
Time and Frequency Normals, Navigation, Underwater Communication, Remote sensing under ground, Maritme telegraphy
Long distance communication (fixed and marite), Broadcasting, Naviagation, Radio beacons
AM broadcasting, naviation, radio beacons, distress frequencies.
Fixed point to point communication, Mobile maritime aeronautical, land services, military communication, amateur radio and broadcasting
Broadcasting, TV, FM, Mobile services for maritime, aeronautical and land, Wireless microphones, Meteor burst communicaiton
Broadcasting TV, satelites, Personal telephone systems, radar systems, fixed and mobile satelite services
Fixed services, Fixed statelite services, Mobile serivces, Remote sensing
Frequency assaignments up 60 GHz
Frequency Hz
3-30 kHz
kHz
KHz
3-30 MHz
MHz
MHz
3-30 GHz
GHz
Wavelength
1000
-100 km
100
-10 km 10
-1 km
-100 m
-10 m
-1 m
-10 cm
-1 cm
-1 mm
Term
ELF
VLF LF MF HF
VHF
UHF
SHF
EHF

7. The Radio Spectrum The frequency spectrum is a shared resource.
Radio propagation does not recognize geopolitical boundaries.
International cooperation and regulations are required for an efficient use of the radio spectrum.
The International Telecommunication Union (ITU) is an agency, within the UN, that takes care of this resource.
Frequency assignment.
Standardization.
Coordination and planning of the international telecommunication services.

8. Evolution of Wireless Systems
[Stallings., 2005]

9. Evolution of Cellular Systems
AMPS
USDC
IS-136
CDPD
TD-SCDMA
ETACS
GSM
GPRS
EDGE
WCDMA
NMT
CDMA
IS-95
CDMAone
IS-95B
CDMA2000 1G 2G
2.5G 3G
[Slimane]

10. Radio Communication Three main problems: The path loss Noise
Sharing the radio spectrum

11. Communication Systems
Message
signal
Source of
information
Transmitter
Transmitted signal
Channel
Estimate of
message signal
Received signal
Receiver
Information
sink
[Ahlin et. al., 2006]

12. Analog Communication System
Source of
information
Signal
Processing
Modulator
RF-Stage
Channel
Information
sink
Signal
Processing
Demodulator
RF-Stage
[Slimane]

13. Digital Communication System
Source of
Information
Source
Encoder
Channel
Encoder
Digital
Modulator
Modulator
RF-Stage
Channel
Information
Sink
Source
Decoder
Channel
Decoder
Digital
Demodulator
Demodulator
RF-Stage
[Slimane]

14. decibels
The bel is a logarithmic unit of power ratios. One bel corresponds to an increase of power by a factor of 10 relative to some reference power, Pref.
The bel is a large unit, so that decibel (dB) is almost always used:
The above equation may also be used to express a ratio of voltages (or field strengths) provided that they appear across the same impedance (or in a medium with the same wave impedance):
[Saunders, 1999]

15. decibels Unit Reference Power Application dBW 1 W Absolute power dBm
1 mW
P [dbW] = P [dBm] - 30
dBmV
1 mV
Absolute voltage, typically at the input terminals of a receiver dB
any
Gain or loss of a network
dBmV/m
1 mV/m
Electric field strength
dBi
Power radiated by and isotropic reference antenna
Gain of an antenna
dBd
Power radiated by a half-wave dipole
0 dBd = 2.15 dBi
[Saunders, 1999]