Differences between LTE and WiMAX

LTE and WiMax may be two peas in an OFDM pod, but they are not twins. Here are three significant differences:

1. Both use orthogonal frequency division multiple access (OFDMA) in the downlink. But WiMax optimizes for maximum channel usage by processing all the information in a wide channel. LTE, on the other hand, organizes the available spectrum into smaller chunks. This translates into higher power consumption, for WiMAX. An architecture that exploits the principles of SDR, however, could reconfigure its FFT function for better power efficiency.

2. LTE uses single-carrier frequency division multiple access (SC-FDMA) for uplink signaling, while WiMax sticks with OFDMA. LTE opted for the SC-FDMA specifically to boost power efficiency. Programmable solutions may be flexible enough to reuse gates and keep power low in LTE mode.

3. WiMax implementations are predominantly Time-Division Duplex (TDD). LTE seems to be heading in the Frequency-Division Duplex (FDD) direction with separate up and downstream channels. A WiMax TDD radio is simpler and makes techniques like beamforming easier.