Review of Radio Propagation Models for Cellular Network Planning

Radio propagation modelling is essential in the planning and deployment of mobile wireless communication systems. These models help to estimate the mean path loss based on parameters such as antenna heights of the transmitter and receiver, distance between them etc. Various propagation models (Okumura-Hata model, Walfisch-Ikegami, COST-231 model etc) exist for predicting signal coverage, achievable data rates, BER and antenna gain. They are described below.

Okumura-Hata Model

Okumura Propagation model was developed in the mid-1960s and was designed for use mostly in urban environment. It is one of the most widely used models for signal prediction, for frequency range between 150MHz - 1920MHz, distance range from 1km-10km, mobile antenna heights of 1-10m, base station antenna height range from 30-200m. Okumura model is known for its slow response to rapid changes in terrain. Okumura model was built into the following three modes: Urban [Built-up city or town with tall buildings and houses of two or more stories, larger villages with close houses and grown trees], Suburban [Village or highway scattered with trees], Open areas [ Locations with Open Space, no tall trees or buildings].

Coverage by Signal level prediction using Okumura-Hata model on Atoll Planning Software

COST 231-Hata Model

COST 231 radio propagation model extends the Hata model to cover a more elaborate range of frequencies between 1500-2000Mhz which encompasses the 1800MHz frequency used for 2G & 3G cellular system, base station antenna height 30-200m, mobile station antenna height 1-10m, link distance 1-20km. This model is restricted to applications where the base station antenna is above the adjacent roof tops.

Coverage by Signal level prediction using COST 231-Hata model on Atoll Planning Software

WALFISCH IKEGAMI Model

This model distinguishes between line-of-sight(LOS) and none-line-of-sight (NLOS) cases and is used for signal prediction for frequency range 800 to 2000MHz, base station height 4-50m, mobile antenna height 1-3m and link distance 200m to 5km. The Walfisch-Ikegami model is more suitable for suburban areas with antenna heights above roof-top.

References:

[1] John S. Seybold, Introduction to RF Propagation.

[2] RF Propagation, Okumura and Hata Macroscopic Propagation Models.