Measurement Journal Issue 6

HSPA review HSPA is an evolution of 3GPP W-CDMA Release 99 and works with existing spectrum and carriers. However, it adds high-speed downlink packet access (HSDPA) for enhanced performance in the downlink, and an enhanced uplink, more commonly known as high-speed uplink packet access (HSUPA), for improved data-rate performance in the uplink. The new features of HSDPA and HSUPA are summarized in Tables 1 and 2, respectively. Table 1. Key features of HSDPA Feature High-speed downlink shared channel (HS-DSCH) 2 ms transmission time interval (TTI) 16QAM modulation Purpose New shared downlink transport channel that allows certain channel codes and transmission power in a cell to be considered a common resource to be shared among users and allocated dynamically for greater efﬁciency. Downlink transmission time interval is much shorter than the 10, 20 and 40 ms TTI speciﬁed in W-CDMA. Channel codes are allocated dynamically every 2 ms, a total of 500 times per second, thus reducing roundtrip time for an IP packet. Allows other features to change rapidly. Higher-order modulation using 16QAM in addition to QPSK, the modulation format currently used in W-CDMA. 16QAM can provide twice the peak data rate of QPSK but requires better radio-channel conditions. Fast method of compensating for varying RF conditions in the downlink by adjusting the transmitted data rate up or down while maintaining transmission power at a constant rate. Technique that estimates the instantaneous radio conditions of the downlink channel to each mobile phone in the serving area and determines to which phone the shared channel resource will be directed during each TTI. Method by which the mobile phone can request retransmissions of missing data to be combined with the original transmission, allowing original transmission to be decoded as quickly as possible. New MAC sub-layer that supports HSDPA transmission with minimal impact on the existing radio interface protocol architecture. Link adaptation Fast packet scheduling Hybrid automatic repeat request (HARQ) MAC-hs Table 2. Key features of HSUPA Feature Enhanced dedicated channel (E-DCH) 2 or 10 ms transmission time interval (TTI) Scheduling Purpose New transport channel that is dedicated to a single user and supports transmission of up to four codes to increase the uplink data rate. Uplink TTI is much shorter than the 10, 20 and 40 ms TTI speciﬁed in W-CDMA. Reduces roundtrip time for an IP packet. Allows other features to change rapidly. Technique for enabling fast reallocation of uplink resources among mobile phones by exploiting the bursty nature of packet data transmissions. Allows the system to support more high-data-rate users. Method by which the base station can request retransmissions of missing data to be combined with the original transmission, allowing original transmission to be decoded as quickly as possible. Hybrid automatic repeat request (HARQ) HSPA-enabled phones must be able to handle the new features. Therefore, different UE categories have been speciﬁed to accommodate low-end and high-end implementations. Each category supports a different combination of features. For example, the 12 UE categories for HSDPA support different numbers of codes, modulation formats, TTI, and peak data rates — from 1.2 Mbps at the low end to the maximum of 14.4 Mbps at the high end. For HSUPA, six UE categories combine different numbers of codes, spreading factors, TTI, and peak rates. A maximum data rate of 5.76 Mbps with 2-ms TTI is speciﬁed at the high end. Agilent Measurement Journal 32

Table of Contents Feed for the Digital Edition of Measurement Journal Issue 6

Measurement Journal Issue 6 Using a Few Words to Convey a Deeply-Held Spirit Charting a Unique Path to Technology Innovation Contents Announcing First Commercial GC/MS Metabolites Library Assessing Nonlinear Behavior Testing Combines Form and Function Testing Multiplay Networks Higher Sensitivity LC/MS Easing Military Radio Test Stepping Up Calibration Accuracy Increasing Spectrum Analyzer Bandwidth 3GPP Tool Supports TS 36 Standards The Olympic Story Spotlights Agilent's Continuing Contribution to Technology Innovation Ensuring a Level Playing Field in Competitive Sports GPS: Coming of Age Resolving Design Issues in HSPA Mobile Devices Achieving Accurate Results with Oscilloscope-Based Jitter-Analysis Software RF Handheld Testers Guarantee Traffic Stability Under Olympic-Sized Stress Conditions Utilizing LAN-Based Instrumentation to Measure Total Harmonic Distortion in Remote Facilities IMT-Advanced: 4G Wireless Takes Shape in an Olympic Year EPO Doping: A Speed Engine, Turbo-Charged by Chemistry

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.