Basics of LTE Understanding

Before we start discuss anything first come to knowledge that IMT has set some requirements that must be fulfilled to qualify for 4G naming.
IMT-Advanced standard requirements

The main purpose of these processing is to provide better speed and reliability on wireless side of mobile communication.

• Peak download rates of 326.4 Mbit/s for 4x4 antennae, and 172.8 Mbit/s for 2x2 antennae (utilizing 20 MHz of spectrum).
• Peak upload rates of 86.4 Mbit/s for every 20 MHz of spectrum using a single antenna.
• Five different terminal classes have been defined from a voice centric class up to a high end terminal that supports the peak data rates. All terminals will be able to process 20 MHz bandwidth.
• At least 200 active users in every 5 MHz cell. (Specifically, 200 active data clients)
• Sub-5 ms latency for small IP packets.
• Increased spectrum flexibility, with supported spectrum slices as small as 1.4 MHz and as large as 20 MHz (W-CDMA requires 5 MHz slices, leading to some problems with roll-outs of the technology in countries where 5 MHz is a commonly allocated amount of spectrum, and is frequently already in use with legacy standards such as 2G GSM and cdmaOne.) Limiting sizes to 5 MHz also limited the amount of bandwidth per handset
• In the 900 MHz frequency band to be used in rural areas, supporting an optimal cell size of 5 km, 30 km sizes with reasonable performance, and up to 100 km cell sizes supported with acceptable performance. In city and urban areas, higher frequency bands (such as 2.6 GHz in EU) are used to support high speed mobile broadband. In this case, cell sizes may be 1 km or even less.
• Good support for mobility. High performance mobile data is possible at speeds of up to 350 km/h, or even up to 500 km/h, depending on the frequency band used.
• Co-existence with legacy standards (users can transparently start a call or transfer of data in an area using an LTE standard, and, should coverage be unavailable, continue the operation without any action on their part using GSM/GPRS or W-CDMA-based UMTS or even 3GPP2 networks such as cdmaOne or CDMA2000)
• Support for MBSFN (Multicast Broadcast Single Frequency Network). This feature can deliver services such as Mobile TV using the LTE infrastructure, and is a competitor for DVB-H-based TV broadcast

E-UTRAN Air Interface

E-UTRAN is the air interface of LTE. Its main features are:

• Peak download rates up to 292 Mbit/s and upload rates up to 71 Mbit/s depending on the user equipment category.
• Low data transfer latencies (sub-5 ms latency for small IP packets in optimal conditions), lower latencies for handover and connection setup time than with previous radio access technologies.
• Support for terminals moving at up to 350 km/h or 500 km/h depending on the frequency band.
• Support for both FDD and TDD duplexes as well as half-duplex FDD with the same radio access technology
• Support for all frequency bands currently used by IMT systems by ITU-R.
• Flexible bandwidth: 1.4 MHz, 3 MHz, 5 MHz, 15 MHz and 20 MHz are standardized.
• Support for cell sizes from tens of metres radius (femto and picocells) up to 100 km radius macrocells
• Simplified architecture: The network side of EUTRAN is composed only by the enodeBs
• Support for inter-operation with other systems (e.g. GSM/EDGE, UMTS, CDMA2000, WiMAX...)
• Packet switched radio interface.