HIGH SPEED DOWNLINK PACKET ACCESS(HSDPA)

[Merry]

HIGH SPEED DOWNLINK PACKET ACCESS(HSDPA)

High Speed Downlink Packet Access (HSDPA) is a packet based technology for W-CDMA downlink with data transmission rates of 4 to 5 times that of current generation 3G networks (UMTS) and 15 times faster than GPRS. The latest release boosts downlink speeds from the current end-user rate of 384 kbps (up to 2 Mbps according to standards) to a maximum value according to standards of 14.4 Mbps. Real life end-user speeds will be in the range of 2 to 3 Mbps.

HSDPA provides a smooth evolutionary path for Universal Mobile Telecommunications System (UMTS) networks to higher data rates and higher capacities, in the same way as Enhanced Data rates for GSM Evolution (EDGE) does in the Global System for Mobile communication (GSM) world. The introduction of shared channels for different users will guarantee that channel resources are used efficiently in the packet domain, and will be less expensive for users than dedicated channels.

HSDPA was introduced in the Third Generation Partnership Project (3GPP) release 5 standards. Assuming comparable cell sizes, it is anticipated that by using multi-code transmission it will be possible to achieve peak data rates of about 10 Mbit/s (the maximum theoretical rate is 14.4 Mbit/s). This will result in a six- to seven-fold throughput increase during an average downlink packet session compared with the Downlink Shared CHannel (DSCH) standards of 3GPP release 99.

3GPP standards beyond release 5 will aim to achieve further throughput increases, say peak data rates in the range 20 to 30 Mbit/s, by using Multiple Input Multiple Output (MIMO) or other antenna array techniques, and possibly asymmetric allocation of frequency spectrum in multi-carrier cells (e.g. a further 100% downlink packet session throughput increase by allocating an additional 5 MHz unpaired band).
HSDPA achieves its performance gains from the following radio features:

High speed channels shared both in the code and time domains

Adaptive modulation and coding schemes: Quadrature Phase Shift Keying (QPSK) and 16QAM (Quadrature Amplitude Modulation).

Hybrid Automatic Repeat reQuest (HARQ) retransmission protocol.

Short transmission time interval (TTI)

Fast packet scheduling controlled by the Medium Access Control - high speed (MAC-hs) protocol in Node B.

Fast scheduling

[basa]

[attachment=4752]
High-Speed Downlink Packet Access

abstract

High-Speed Downlink Packet Access (HSDPA) is an enhanced 3G (third generation) mobile telephony communications protocol in the High-Speed Packet Access (HSPA) family, also coined 3.5G, 3G+ or turbo 3G, which allows networks based on Universal Mobile Telecommunications System (UMTS) to have higher data transfer speeds and capacity. Current HSDPA deployments support down-link speeds of 1.8, 3.6, 7.2 and 14.0 Mbit/s. Further speed increases are available with HSPA+, which provides speeds of up to 42 Mbit/s downlink and 84 Mbit/s with Release 9 of the 3GPP standards.[1].

[swathikakulla]

I M VIRAL SHAH.I STUDY IN B.E. LAST YEAR IN COMPUTER.I WANT REPORT ON HSDPA.