OFDM Introduction

OFDM (Orthogonal Frequency Division Multiplexing) is a digital multi-carrier modulation scheme that uses a large number of orthogonal sub-carriers that are closely spaced. Sub-carrier frequencies are chosen such that the sub-carriers are orthogonal to one another which results in the elimination of crosstalk. This modulation scheme also enables high spectral efficiency and as a result nearly the entire frequency band can be utilized. OFDM is an optimal solution for wideband communications since it can use cost effective DSP chipsets.

OFDM Applications include:

• ADSL and VDSL broadband access
• Certain Wi-Fi LANs: IEEE 802.11a/g
• DAB and HD radio systems
• Digital TV systems: DVB-T, DVB-H, T-DMB
• WiMAX (IEEE 802.16)
• Ultra Mobile Broadband (UMB or IEEE 802.20)
• Flash-OFDM cellular systems
• Optical fiber communications systems

The OFDM communication systems can be designed to operate at various frequencies. Also the AP60x devices operate from 800MHz to 2350MHz, hence, can be easily be used into non-cellular applications like the OFDM communication systems.

 

Moreover the AP60x products have proved to be a robust alternative to LDMOS devices.

 

In this particular application of OFDM, the frequency band is 1760MHz to 1840MHz. The AP60x devices could be used as pre-driver or driver stage PAs in higher output power systems, and for lower output power systems, the AP603 device can be implemented.