Modulation Techniques in LTE LTE devices use several modulation techniques to modulate data and control information. These modulation techniques include: QPSK (2 bits per symbol), 16QAM (4 bits per symbol), and 64QAM (6 bits per symbol). All of these modulation techniques are supported in the downlink direction; and all but 64QAM, which is optional, are … Read more
MULTIPLE ANTENNA TECHNOLOGY IN LTE The use of multiple antenna technology allows the exploitation of the spatial domain as another new dimension. This becomes essential in the quest for higher spectral efficiencies With the use of multiple antennas the theoretically-achievable spectral efficiency scales linearly with the minimum of the number of transmit and receive antennas … Read more
MULTICARRIER TECHNOLOGIES IN LTE Adopting a multicarrier approach for multiple access in LTE was the first major design choice. The choice of multiple-access schemes was made in December 2005, with OFDMA being selected for the downlink, and SC-FDMA for the uplink. Both of these schemes open up the frequency domain as a new dimension of … Read more
BEAMFORMING in LTE If some knowledge of the downlink channels of the different transmit antennas, (more specifically some knowledge of the relative channel phases) is available at the transmitter side, multiple transmit antennas can be used to shape the overall antenna beam in the direction of a target receiver. In general, such beamforming can increase … Read more
LTE NETWORK ARCHITECTURE OVERVIEW The Long-Term Evolution (LTE) network architecture is a crucial component of modern wireless communication systems. In this overview, we will delve into the key aspects of LTE network architecture, including its structure, nodes, and functionalities. ENodeB: The Radio Access Node At the heart of the LTE network is the ENodeB (eNB), … Read more
Functions of the cdma2000 Signaling Services Layer The Signaling Services Layer processes all messages exchanged between the mobile and the base station. These messages control such things as call setup and tear down, hand offs, feature activation, system configuration, registration and authentication. In the mobile, the Signaling Services Layer is also responsible for maintaining the … Read more
A mobile will in one of four states after it is powered on. Initialization State In the Initialization State, the mobile tunes to the first preferred RF frequency channel and attempts to decode the Pilot Channel. If a pilot is not found, the mobile tries to decode a pilot on another RF channel or … Read more
UL Allocation (SC-FDMA) in LTE SC-FDMA utilizes single carrier modulation, DFT-spread orthogonal frequency multiplexing, and frequency domain equalization. LTE uses OFDMA on the DL. It allocates DL bandwidth to the user based on resource blocks, rather than individual subcarriers. When the signal is a combination of subcarriers, high amplitude power peaks can occur. The base … Read more
Spectrum efficiency DL : 3-4 timesUL : 2-3 times Frequency Spectrum Scalable bandwidth : 1.4, 3, 5, 10, 15, 20MHzTo cover all frequencies of IMT-2000: 450 MHz to 2.6 GHz Peak data rate DL : > 100Mb/s for 20MHz spectrum allocationUL : > 50Mb/s for 20MHz spectrum allocation Latency C-plane : < 100ms to establish U-planeU-plane … Read more
LTE TCP Throughput vs Round Trip Time (RTT) In Long-Term Evolution (LTE) networks, the relationship between TCP throughput and Round Trip Time (RTT) is a critical factor influencing the performance of data transmission. Let’s explore the key considerations: TCP Throughput: Definition: TCP (Transmission Control Protocol) throughput refers to the rate at which data can be … Read more