0 kHz TETRA Figure D.5 TETRA spectrum usage encode the voice and to build the frame. The physical channel is obtained by assembling the timeslots belonging to different frames. The frequency bands standardised by CEPT for TETRA are the following: 380-390 MHz and 390-400 MHz 410-420 MHz and 420-430 MHz 450-460 MHz and 460-470 MHz 806-824 MHz and 851-869 MHz TETRA Network Planning Time division multiplexing Speech Coding Channel Coding 4 ACELP 4.56kbps 7.2 kbps 12341234 Frame 1 Frame 2 Figure D.6 Channel coding and frames D.4.2 TETRA Memorandum of Understanding The objective of the TETRA Memorandum of Understanding (MoU) is to support and promote the TETRA standard worldwide and to provide a forum to share and exchange information and ideas among a wide variety of individuals who share a common interest in the success of the standard. The purpose of the TETRA MoU is to: support the ETSI project TETRA to the full extent; support the initiative to obtain additional TETRA frequencies; develop a TETRA certification mark that will uniquely identify all equipment meeting the TETRA standard; ensure appropriate cooperation and support of the validation process of TETRA. On the TETRA MoU website, the interoperability certificate for radio terminals and infrastructure can be found (www.tetramou.com). D.5 Introduction to TETRA Network Planning Although the general network planning process is very similar to the one applied to other cellular technologies, the network planning for TETRA usually differs from the network planning of other commercial cellular networks because it applies to particular customer requirements, such as high network availability, wide area coverage, low investment and protection of ones already done in the past. The general network planning process is usually divided into the following steps (Figure D.7): Radio network planning Traffic capacity network planning Frequency planning Transmission and core network planning Each of these steps could require a loopback to the beginning of the process because t