An Introduction to LTE: LTE, LTE-Advanced, SAE, VoLTE and 4G Mobile Communications, 2nd Edition

Chapter 8Data Transmission and Reception

Data transmission and reception is one of the more complex parts of LTE. In this chapter, we begin with an overview of the transmission and reception procedures that are used in the uplink and downlink. We then cover the three main stages of those procedures in turn, namely, the delivery of scheduling messages from the base station, the actual process of data transmission and the delivery of acknowledgements and any associated control information from the receiver. We also cover the transmission of uplink reference signals as well as two associated procedures, power control and discontinuous reception.

Several 3GPP specifications are relevant to this chapter. Data transmission and reception is defined by the physical layer specifications that we noted earlier, particularly TS 36.211 [1], TS 36.212 [2] and TS 36.213 [3], and is controlled by the MAC protocol in the manner defined by TS 36.321 [4]. In addition, the base station configures the mobile's physical layer and MAC protocols by means of RRC signalling [5].

8.1 Data Transmission Procedures

8.1.1 Downlink Transmission and Reception

Figure 8.1 shows the procedure that is used for downlink transmission and reception [6, 7]. The base station begins the procedure by sending the mobile a scheduling command (step 1), which is written using the downlink control information (DCI) and transmitted on the physical downlink control channel (PDCCH). The scheduling command alerts the mobile ...