《《HSDPA_Mobile_Broadband_Data》.pdf

HSDPA Mobile Broadband Data A Smarter Approach to UMTS Downlink Data UMTS mobile wireless systems have enjoyed widespread uptake of high-quality circuit-switched applications like voice and video telephony. However, they have yet to deliver to the vision of ubiquitous mobile data – primarily due to the absence of an efficient high-speedpacket-switched data transmission platform. Data services like mobile internet access require asymmetric packet switched networks to best utilise the available spectrum in a multiuser environment. High-speed downlink packet access (HSDPA) in release 5 of the UMTS standard provides high-speed downlink data channels that can be shared efficiently between multiple users. It offers increased data rates (up to 14 Mbits/s), as well as improved error control handling and other techniques that increase the overall performance of the network. In this paper, we describe the characteristics of HSDPA systems and explain how they will enable the widespread deployment of cost-effective mobile broadband data services. Voice and video telephony have symmetric bandwidth needs with strict latency and quality of service (QoS) requirements. These are met in today’s release 99 UMTS networks using dedicated circuit-switched data channels (DCH) that provide up to 384 Kbits/s in both uplink and downlink transmissions. However, these channels are not readily shared between users. The next release of the UMTS standard (known as release 4) provides a downlink shared channel (DSCH) which is a radio link that can be assigned to a different user every 10 ms. Although DSCH was defined in release 99, support of the feature was not mandatory and it has yet to be deployed in a UMTS network. HSDPA offers high-speed downlink shared channels (HS-DSCH) that can switch between users every 2 ms. Using these channels, HSDPA systems can offer excellent packet- switched data services to several users simultaneously and efficiently. HSDPA Physical Chan