User Manual

2 Introduction
ID No: 163511 Page 11
2. INTRODUCTION
2.1. PURPOSE
Cellular telephone systems transmit signals in two directions between base
transceiver station (BTS) and mobile stations (MS) within the signal coverage area.
If weak signal transmissions occur within the coverage area because of indoor
applications, topological conditions or distance from the transmitter, extension of the
transmission range can be achieved by means of an optical distribution system.
Such a system contains an optical master unit and a remote unit. The number of the
remote unit depends on the hardware and software configuration. The remote unit is
connected to the master unit with optical links. The optical loss must be less than 10
dB inclusive optical couplers or splitters.
The master unit is the connection to the base transceiver stations. The configuration
of a master unit depends on the number of the remote units and the frequency range.
The optical transmission uses WDM-systems with a wavelength of 1550 nm in the
uplink and 1310 nm in the downlink.
2.2. THE MMR8L L SINGLE BAND REMOTE UNIT
The MMR8L L is a single-band multi-operator remote unit. It is used in conjunction
with a master unit in the MMR optical distribution system. This system transports the
whole LMR band simultaneously providing a cost effective solution for distributing
capacity from one or more base stations.
The MMR8L L transports signals on the RF layer in a very inexpensive manner. This
means that services from various operators can be transmitted simultaneously from a
cluster of base station to a remote location over the same fibre.