Tag Archives: amplitude

WCDMA Modulation

Different modulation methods corresponding to different transmitting abilities in air interface. R99/R4: QPSK HSDPA: QPSK or 16QAM The UTRAN air interface uses QPSK modulation in the downlink, although HSDPA may

Inter-Symbol Interference in LTE

What is the multipath? Due to the signal propagation phenomena, like reflection or diffraction, a receiver can receive several delayed versions of the same signal. This creates Inter-Symbol Interference (ISI).

Constellation in LTE

The QPSK is the most robust modulation. It can be represented by a constellation: The radius, R, represents the amplitude. The angle, ?, represents the phase. There are 1 amplitude

Modulation in LTE

The 3G LTE uses 3 Quadrature Amplitude Modulations (QAMs) depending on the radio quality. QAM uses both the amplitude and the phase. The LTE supports in DL and UL the

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,

Pulse shaping and spectrum in LTE

RF engineering is a trade off between: required radio spectrum (bandwidth), speed of data transmission (bit rates) and complexity of implementation. The pulse form used to modulate complex data symbols