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E8887 HSPA (High-Speed Packet Access) Wireless Library |  |
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The High Speed Uplink Packet Access (HSUPA) wireless library is based on 3GPP FDD enhanced uplink, defined in release 6 of 3GPP specification. This design library focuses on the physical layer aspects of HSDPA/HSUPA systems and is intended to be a baseline system for designers to get an idea of what nominal or ideal system performance would be. With the High Speed Downlink Packet Access (HSDPA) wireless library, there is only high data rate downlink capability. There are a number of benefits to a balanced downlink/uplink in 3G Cell Phone applications. For example, there are user applications that transmit large amounts of data from mobile station, such as a user sending a video clip or a business user sending a large presentation file. It is also beneficial to balance the capacity of uplink with the capacity of downlink for future applications such as Voice over IP. For HSDPA content in this library, new physical channels: HS-PDSCH, HS-SCCH and transport channels: HS-DSCH plus uplink physical channel HS-DPCCH are added. The transport channels and physical channels defined in release 5 and previous versions of 3GPP specification such as DCH, DPDCH are also supported by HSUPA design library and they are treated as the necessary channels because HSUPA focuses on the modeling and test of channels defined in release 6. HSPA Wireless Library provides preconfigured simulation setups, signal sources and fully coded BER analysis for simulation of the circuitry used in 3GPP fast uplink designs. They help speed the development cycle by allowing system designers to analyze a system's performance before all of its components are designed. The HSPA wireless library works within the ADS environment and with the Agilent Ptolemy simulator and contains the new technologies such as shorter Transmission Time Interval (TTI) and Hybrid Automatic Repeat Request (HARQ) and new specifications such as Throughput. HSPA Wireless Library also can be imported into Agilent RF Design Environment (RFDE), allowing RFIC designers to access 3GPP fast downlink/uplink test benches within the Cadence Virtuo Custom IC platform through links developed as part of the ongoing alliance between Agilent and Cadence Design Systems. Why HSUPA?Balanced downlink/uplink Current HSDPA technology is an unbalanced system, with a maximum of 14 Mbit/s on the downlink and 2 Mbit/s on the uplink, from the terminal to the network. That can be a concern if acknowledgments are slow from terminal, reducing the downlink rate. Release 6 of the 3GPP specification will change that by introducing high-speed uplink packet access (HSUPA). This allows users to take advantage of faster uplinks with lower latency when sending large files or emails. That in turn improves the efficiency of the link, increasing effective throughput, even though the modulation has not changed. Indeed, without the improved efficiency of HSUPA, it is highly likely that HSDPA will be impaired in applications that have more balanced bandwidth needs. HSPA vs. 3GPP FDD Specifications
Improvement on Downlink
Improvement on Uplink
HSDPA Downlink StructureHSUPA Uplink StructureKey Technologies in HSPAHybrid ARQ (Automatic Repeat Request)An advanced retransmission strategy, which allows performing possible retransmissions directly at physical layer, without involving higher layer mechanisms and so reducing the delay and increasing the throughput. Shorter TTI (Transmission Timing Interval)Adaptive Modulation and Coding (AMC)Link adaptation is one important way in which HSDPA improves data throughput. The technique used, AMC, varies the downlink modulation-coding scheme depending on the channel conditions for each user. The power of the transmitted signal is held constant over a sub-frame interval, and the modulation and coding format are changed to match the current received signal quality or channel conditions at the receiver. In this scenario, users close to the BTS are typically assigned higher order modulation with higher code rates (for example, 16 QAM with an effective code rate of 0.89), but the modulation-order and code rate will decrease as the distance from the BTS increases. 1/3 rate turbo coding is used and different effective code rates are obtained through various rate-matching parameters. Code Multiplexing Combined with Time MultiplexingTo obtain higher data rates and greater spectral efficiency, relative to Release 99's code domain multiplexing (CDM), both CDM and time domain multiplexing (TDM) are used in HSDPA downlink transmission. Multiple UEs can receive information in the same subframe by using different parts of the orthogonal variable spreading factor (OVSF) code space for HS-PDSCH. HS-PDSCH can also multiplex several users in the time domain. HARQ Implementation in HSUPAHARQ and AMC Implementation in HSDPAData Display in ADS: HSUPA Throughput Measurement vs. Ec/N0Data Display in ADS: HSDPA Throughput Measurement vs. Ec/N0Glossary of Terms
Required ADS ModulesBesides the E8887 HSPA Library the other ADS modules needed are:
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