Despread Trace Data (W-CDMA(3GPP)/HSPA)

Despread Channel (x) trace data are Time domain data results for a single Code Channel (Code Channel) within a specified code layer (Spread Code Length/Symbol Rate). The trace data results includes both time domain IQ trace data and Symbol/Error table data.

HSPA+MIMO Despread Channel Trace Data

The VSA also supports measurement analysis for 2x2 DL Down Link (forward link: from base station to cell phone) MIMO Multiple Input, Multiple Output: A physical layer (PHY) configuration in which both transmitter and receiver use multiple antennas. systems for HS-PDSCH High Speed Physical Downlink Shared Channel signals using flat-fading. Use the Despread Traces parameter to select the MIMO measurement Test Plane. See HSPA+ MIMO Overview for more information.

W-CDMA(3GPP) Uplink measurements

For W-CDMA Code Division Multiple Access: One of several digital wireless transmission methods in which signals are encoded using a specific pseudo-random sequence, or code, to define a communication channel. A receiver, knowing the code, can use it to decode the received signal in the presence of other signals in the channel. This is one of several "spread spectrum" techniques, which allows multiple users to share the same radio frequency spectrum by assigning each active user an unique code. CDMA offers improved spectral efficiency over analog transmission in that it allows for greater frequency reuse. Other characteristics of CDMA systems reduce dropped calls, increase battery life and offer more secure transmission. See also IS-95.(3GPP) Uplink measurements, the "I" and "Q" branches are logically separate signals. All channel trace data results contain both I and Q branch data, except symbol table trace data. The symbol table shows either the "I" symbol bits or the "Q" symbol bits as determined by the I/Q branch setting.

Selecting a Despread Channel

Specify the trace data analysis Despread Channel using the Spread Code Length and Code Channel Despread Channel parameters located in the Channel/Layer Demodulation Properties dialog box (MeasSetup > W-CDMA(3GPP)/HSPA Demod Properties > Channel/Layer tab).

Use the Copy Mkr To Despread Chan marker feature (Marker > Copy Marker To > ...) to automatically enter the Spread Code Length and Code Channel information.

Available Despread Channel Trace Data

Error Vector Time	IQ Phase Error
IQ Mag Error	IQ Ref Time
IQ Meas Time	Syms/Errs