Subframe Info (802.16 OFDM)

The Subframe Info trace data is the new data type to 802.16 OFDM. Subframe Info is both a measurement data type and an associated trace data format.

Subframe Info contains a large amount of important information that bridges the vector and demodulation modes. This trace data summarizes the entire subframe data and power characteristics, including the modulation types used, their relative power, number of symbols and the RCE for each one.

Subframe Info also reports the preamble type and whether the header checksum is correct. Other info such as frame number and the configuration change bit are also included.

The Subframe Info table could be particularly useful for a designer to verify the composition of a subframe after the modulation quality was measured or verified. The number of symbols used by each modulation type could be examined and confirmed, for example, along with the error and signal power associated with each one.

The power of the preamble is 3 dB greater than the data portion of the subframe (RF burst). This is called out in the standard and is an intentional characteristic of the signal.

The Subframe Info table shows information about each burst found. For each burst, a single line shows burst power, modulation format, RCE and length in symbols

This table shows the type of preamble detected. Possible values include Long, Short, STC, AAS and Subchannel, all of which are defined in the 802.16-2004 standard. If a non-standard preamble is detected, consisting of an optional P4x64 sequence followed by one of the Peven, Psub, Paas or Pall sequences, the names of the sequences detected will be displayed. For example, if a P4x64 sequence followed by a Psub sequence is detected, the table will display P4x64+Psub.

After the detection of the preamble, the FCH detection is shown, followed by details of any detected bursts.

If a frame control header FCH is detected, details of the header are tabulated at the bottom. HCSPassed means that the header check sum has passed.

For more information about how the VSA determines the modulation format, see Data Subcarrier Modulation.

See Also

About Error Summary Data (802.16 OFDM)

Available Trace Data (802.16 OFDM)


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