Indoor Radio Planning: A Practical Guide for GSM, DCS, UMTS, HSPA and LTE, Second Edition

3.5 The Basics of Indoor RF Planning

No matter what the radio service, whether it is GSM, UMTS, HSPA or other technologies, there are some basic design guidelines one must apply in order to design a high-performing indoor coverage solution.

3.5.1 Isolation is the Key

If you must select one parameter and one parameter only that truly defines the most important success parameter when designing an IB solution, it must clearly be the ‘isolation’. Isolation is defined as the difference between the IB signal and the outdoor network, and vice versa.

Users in office buildings are typically close to the windows; therefore the dominance of the indoor system must be maintained throughout the building, even right next to the windows.

3.5.2 Tinted Windows Will Help Isolation

Modern energy-efficient windows with a layer of thin metallic coating will attenuate the macro signal servicing the building. This type of window will attenuate the RF signal from the outdoor network, and create a need for a dedicated indoor solution.

The positive side effect of this ‘problem’ is that, once the indoor system is installed, these metallic-coated windows will actually help the design, giving us good isolation. These types of windows with a thin layer of metallic coating will typically attenuate the signal by 20–40 dB, depending on the radio frequency, and the incident angle of the radio signal.

Recently new types of windows are being used, or film applied to existing windows in high-profile office buildings. ...