Based on Lecture series UNIK4700 and the Building_Mobile_and_Wireless_Networks_Compendium.

Disclaimer: This compendium provides information on aspects of radio wave propagation, antennas, system aspects, and handover schemes for mobile and wireless systems. The compendium is foreseen for the UNIK4700 course on Building Mobile and Wireless Networks, and is kept on the system aspects level. UNIK has several courses on Radio and Network technologies as part of the Wireless Networks and Security (WNaS) research area.

The compendium contains slides and explanations. The slides are scientific topics, examples, and exercises, and should be presented as slides to the students. Explanations and presenter notes, or written text to explain difficult content, should be omitted in "slideshow" mode, and be only visible in in "normal" mode.

Main focus in the previous lectures was on propagation effects. We will first repeat the main conclusions from last lecture on electromagnetic signals, and then introduce the capacity of a system based on Shannon's theorem.

New literature:

• J. Noll, K. Baltzersen, A. Meiling, F. Paint , K. Passoja, B. H. Pedersen, M. Pettersen, S. Svaet, F. Aanvik, G. O. Lauritzen. '3rd generation access network considerations'. selected pages from Unik/FoU R 3/99, Jan 1999 (.pdf]])
• H. Holma, A. Toskala (eds.), "WCDMA for UMTS", John Wiley & sons, Oct 2000, selected pages

,

where P is average power

• why talking about noise?
• dB,
• near-far problem

[source: Wikipedia]

• The fundamental theorem of information theory, or just Shannon's theorem, was first presented by Claude Shannon in 1948.
• Given a noisy channel with channel capacity C and information transmitted at a rate R, then if R < C there exist codes that allow the probability of error at the receiver to be made arbitrarily small. This means that theoretically, it is possible to transmit information nearly without error at any rate below a limiting rate, C.

• See File:LarsLundheim-Telektronikk2002.pdf: The channel capacity of a band-limited information transmission channel with additive white, Gaussian noise. This capacity is given by an expression often known as “Shannon’s formula”: [bits/s]

with W as system bandwidth, and in case of interference free environment, otherwise , where with as Boltzmann constant and as temperature in Kelvin.

[bits/s]

Exercises

• calculate capacity for W= 200 kHz, 3.8 Unik/MHz, 26 Unik/MHz, (all cases P/N = 0 dB, 10 dB, 20 dB)
• If the SNR is 20 dB, and the bandwidth available is 4 kHz, what is the capacity of the channel?
• If it is required to transmit at 50 kbit/s, and a bandwidth of 1 MHz is used, what is the minimum S/N required for the transmission?

[source: Wikipedia, Telektronikk 2002]