Baseband signal processing in SDR

Wireless communications free users from being attached to wires and allow them to remain connected even when they move around at home or are on the road. Services that support high throughput yet cost little or even nothing are attractive to the consumers. Today, Code-Division Multiple Access (CDMA) technology makes up the foundation of 3G cellular system and Global Positioning System (GPS). Many other wireless standards are based on multi-carrier modulation technology (specifically OFDM). Multi-carrier modulation technology enjoys flexible spectral resource allocation and management as well as easy equalization. On the other hand, antenna array and spatial MIMO processing, which have been around for several decades, can provide spatial diversity gain and/or channel capacity increase. The application of the MIMO technology to wireless communications takes place only recently, exemplified by its adoption in IEEE 802.11n, IEEE 802.16e, and 3GPP LTE. In this talk I will address the above three important baseband technologies using insightful illustrations. In addition, I will give a design example using our previous work on software GPS receiver.