Chapter 9
Downlink Physical Data and Control Channels
9.1 Introduction
Chapters 7 and 8 have described the signals which enable User Equipment (UEs) to synchronize with the network and estimate the downlink radio channel in order to be able to demodulate data. This chapter first reviews the downlink physical channels which transport the data and then explains the control-signalling channels; the latter support the data channels by indicating the particular time-frequency transmission resources to which the data is mapped and the format in which the data itself is transmitted.
9.2 Downlink Data-Transporting Channels
9.2.1 Physical Broadcast Channel (PBCH)
In cellular systems, the basic System Information (SI) which allows the other channels in the cell to be configured and operated is usually carried by a Broadcast CHannel (BCH). Therefore the achievable coverage for reception of the BCH is crucial to the successful operation of such cellular communication systems; LTE is no exception. As already noted in Chapter 3, the broadcast (SI) is divided into two categories:
- The ‘Master Information Block’ (MIB), which consists of a limited number of the most frequently transmitted parameters essential for initial access to the cell,1 and is carried on the Physical Broadcast CHannel (PBCH).
- The other System Information Blocks (SIBs) which, at the physical layer, are multiplexed with unicast data transmitted on the Physical Downlink Shared CHannel (PDSCH) as ...
