UL User#

To access the UL burst editing window:

Expand MAC-Uplink in the tree view and click the UL User# you want to edit.
or
Click MAC-Uplink in the tree view to display all previously added bursts in the right pane. Double-click in the first column of the burst that you want to edit.

The UL burst editing window displays the UL burst parameters in the top pane and buttons for adding MAC PDUs (maximum eight) in the bottom pane.

1. Uplink User

Rate ID

Use this cell to select the burst modulation and coding rate type used for all MAC PDUs for this user (subscriber, SS, or CPE). The modulation types of the uplink user bursts do not have to be in any particular order.

Attenuation

Use this cell to set the relative power for each uplink user. Power can be attenuated by 0 dB to 40 dB to simulate bursts arriving from different users with different path losses. There must be at least one UL user burst with 0.0 dB attenuation to allow the signal generator to calibrate its power output.

Time Offset [samples]

Use this cell to set the relative time offset in integral units of the sample for the start of this user's burst. A zero value indicates that the burst starts exactly when scheduled. Offset values can be used to simulate time-of-arrival differences between different user transmissions. Setting the Time Offset [us] recalculates this value.

Time Offset [us]

Use this cell to set the relative time offset for the start of the user's burst. A zero value indicates that the burst starts exactly when scheduled. Values ranging from –10 to 10 microseconds can be used to simulate time-of-arrival differences between different user transmissions. Setting the Time Offset [samples] recalculates this value.

Midamble Repetition Interval

Use this cell to insert optional embedded midamble and postamble symbols in an uplink transmission. Midambles may be inserted every 4, 8, or 16 symbols with a postamble symbol at the end.

Ranging Burst Mode

Use this cell to select the ranging burst mode on or off. Ranging allows the subscriber station to acquire the correct timing offset and power adjustments from the base station. Initial ranging allows the user to establish a link with a base station when it first starts up and to receive a CID assignment. Ranging bursts have a long preamble and are transmitted during the ranging interval time of the frame. User bursts have a short preamble and are transmitted after the request and bandwidth allocations.

Subchannel Index

Use this cell to select the subchannel index to be used. Refer to Table 213, OFDM Symbol Parameters, in the 802.16 specification, section 8.3.2 for the full definition of uplink subchannelization and use of specific subcarriers and pilot tones.

  • Subchannel index 16 is a full use of all 192 subcarriers in each OFDM symbol. Odd numbered indexes (1 to 31) are 1/16 size subchannels using 12 subcarriers in each OFDM symbol. Indexes 8 and 24 are 1/2 size subchannels (96 carriers). Indexes 4, 12, 20,and 28 are 1/4 size subchannels (48 carriers), and indexes 2, 6, 10, 14, 18, 22, 26, and 30 are 1/8 size subchannels (24 carriers).

  • Symbol power for subchannels is reduced by the ratio of subcarriers used compared to full subchannels. Thus for 1/2 size, the total power is –3 dB, for 1/4 size –6 dB, and so on.

  • Full use of subcarriers includes 8 pilot tones; 1/2 use includes 4 pilot tones; 1/4  use includes 2 pilot tone; 1/8 use includes only 1 pilot tone; 1/16 use has no pilot tones at all.

  • In general, the selected output power of the signal generator is leveled to the highest powered symbol(s) the are defined in the waveform. However, the Signal Studio offers two methods of power reference that can be selected in the Project parameter window by setting the “Amplitude Reference” selection. If you select Preamble, the power will be leveled to the output power of the highest powered preamble symbol. If you select FCH/Burst, the output power will be leveled to the power of the highest powered user or FCH burst symbol.

 

2. Gap Setting

Gap Interval [samples]

Use this cell to insert a transmission gap at the Physical layer after the user's transmission. This may be used to simulate a non-transmitting subscriber station. Setting the Gap Interval [us] recalculates this value. The minimum and default value is zero.

Gap Interval [us]

Use this cell to set a transmission gap in microseconds after the user's transmission. Setting the Gap interval [samples] recalculates this value rounded to an integer number of samples. The minimum and default value is zero.

Occupied OFDM Symbols

This cell tracks the number of symbols used in OFDM generation including preambles, midambles and postambles.

UL MAC PDU

adds a MAC PDU to the selected burst. When you add MAC PDUs (maximum eight) to a burst, a data grid displays some of the parameters that you can edit by clicking each cell. To edit a full set of MAC PDU parameters, see Editing Tip.

Editing Tip: Double-click in the first column of the MAC PDU# or click on the MAC PDU#  in the tree view. This displays the MAC PDU editing window. To return to the burst window, click the corresponding burst in the tree view. For parameter definitions, see MAC PDU.

deletes a previously added MAC PDU.

adds a MAC PDU that has the same configuration as the currently selected burst.

swaps the currently selected burst with the one above it or the one just below it in the table for that link.

Related Website

IEEE 802.16-2004 standard