The design of the LTE physical layer (PHY) is heavily influenced by the requirements for high peak transmission rate (100 Mbps DL/50 Mbps UL), spectral efficiency, and multiple channel bandwidths (1.25-20 MHz). To fulfill these requirements, orthogonal frequency division multiplex (OFDM) was selected as the basis for the PHY layer. OFDM is a technology that dates back to the 1960’s. It was considered for 3G systems in the mid-1990s before being determined too immature. Developments in electronics and signal processing since that time has made OFDM a mature technology widely used in other access systems like 802.11 (WiFi) and 802.16 (WiMAX) and broadcast systems (Digital Audio/Video Broadcast – AB/DVB).
In addition to OFDM, LTE implements multiple-antenna techniques such as MIMO (multiple input multiple output) which can either increase channel capacity (spatial multiplexing) or enhance signal robustness (space
frequency/time coding).
Contents:-
- OVERVIEW
- MULTIPLE ACCESS TECHNIQUES
- PHYSICAL LAYER PARAMETERS
- REFERENCE SIGNALS - Downlink and uplink
- SYNCHRONIZATION SEQUENCES
- PHYSICAL CHANNELS - Downlink and uplink
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