HSDPA, or High-Speed Downlink Packet Access, is a mobile telecommunication technology that enhances the speed and efficiency of data transmission in 3G networks. It allows users to download data at significantly higher rates compared to earlier UMTS standards, making activities like streaming videos and browsing the internet smoother and faster. This technology works by improving the way data is sent from the network to mobile devices. By using advanced techniques like adaptive modulation and coding, HSDPA can provide download speeds of up to 14.4 Mbps, depending on network conditions and device capabilities, thus enhancing the overall user experience.