4G LTE

Single and Multiple User MIMO in the Uplink SU MIMO LTE SU-MIMO is within LTE, but at the time of this writing has not yet been fully identified. To implement the SU-MIMO UE require two transmitters. This is an important problem from the standpoint of cost, size and battery consumption, and for these reasons, SU-MIMO … Read more

Single User and Multi User MIMO codewords in LTE Figure shows how the two codewords are used for a single user in the downlink. It is also possible that the code words to be assigned to different users to create multi-user MIMO (MU-MIMO). Depending on the channel information available in the eNB, modulation and precoding … Read more

Codeword, layer, and precoding in LTE Terms codeword, layer, and precoding have been taken to refer specifically to LTE signals and processing. The figure shows the processing steps to which they relate. The terms used in the following ways: Codeword: codeword represents the user data before it is formatted for transmission. One or two code … Read more

The MIMO channel Matrix Consider for a moment in time, on the same frequency and channel modeling as a black box with durable internal components. If we add two completely different input signals is to be mixed with each other in a certain manner depending on the value of Z1 to Z4. If we send … Read more

Multi-antenna Techniques LTE to improve the downlink performance There are five methods of multiple antennas have been defined for the LTE downlink to improve the performance: Receive diversity at the mobile Transmit diversity using SFBC at the eNB (evolved Node B) MIMO spatial multiplexing at the eNB, for one or two users Cyclic Delay Diversity … Read more

LTE MIMO Types of Inputs and Outputs LTE MIMO “input” and “output” are used for medium between transmitters and receivers, including both RF components – known as the “channel”. Thus, the base station with two transmitters provides two inputs to the channel, “mi” page, and the handset takes two strings get two out of the … Read more

The procedures for the Non Access Stratum, especially power management procedures are substantially similar to UMTS. Main change is that the UMTS EPS allows concatenation certain procedures to allow faster creation of connection and media. Create MME UE context, when the UE is on and attaches to the network. Assign a unique ID called SAE … Read more

LTE core network also called EPC in SAE is responsible for the complete control of the UE and the creation of media. The main logical nodes LTE EPC are: • PDN Gateway (P-GW) • Serving Gateway (S-GW) • Mobility Management Entity (MME) PCRF of LTE Core Network The political control and charging rules is responsible … Read more

EPS provides the user with a PDN IP connectivity for Internet access and for the operation of services such as Voice over IP (VoIP). An EPS bearer is usually associated with a QoS. Multiple carriers may be set for a user, in order to provide different QoS flows and connectivity to different PDNs. For example, … Read more

The air interface is the radio-based communication link between the mobile station and the active base station. LTE air interface supports high data rates. LTE uses Orthogonal Frequency Division Multiple Access (OFDMA) for downlink transmission to achieve high peak data rates in high spectrum bandwidth. LTE uses Single Carrier Frequency Division Multiple Access (SC-FDMA) for … Read more