Detected Allocations Time (LTE-Advanced)
shows the allocations of the selected layer in a two dimensional grid with frequency on the vertical axis and time on the horizontal axis. Each point on the grid represents a single resource element (1 subcarrier x 1 symbol).
Only signals that are selected on the Profile Tab will be shown on this trace.
The time units are symbols by default, but the units can be switched to seconds by clicking and setting to .
The points are color coded according to channel type. The Frame Summary trace shows all the channels and their corresponding colors.
MBMS mixed-mode CP
MBMS Multimedia Broadcast Multicast Service signals are transmitted during the MBSFN region of MBSFN subframes using Extended CP 1) Contention period, or 2) Cyclic prefix mode (6 symbols per slot). The non-MBSFN region of these subframes (and the rest of the frame) can be transmitted in Normal or Extended CP mode.
For mixed-CP-mode LTE Long Term Evolution frames, traces that show time on the x-axis in units of syms (OFDM Orthogonal Frequency Division Multiplexing: OFDM employs multiple overlapping radio frequency carriers, each operating at a carefully chosen frequency that is Orthogonal to the others, to produce a transmission scheme that supports higher bit rates due to parallel channel operation. OFDM is an alternative tranmission scheme to DSSS and FHSS. symbols) would need unevenly spaced x-axis points to correctly represent the time locations of the symbols (since extended CP symbols are longer than normal CP symbols).
Instead of using non-uniform x-axis spacing of symbol points, the LTE demodulator shows the time axis as if all the slots used Normal CP (with 7 symbols per slot), and for MBSFN slots, the demodulator fills the first 6 symbols of the slot with the extended CP symbols, leaving the 7th symbol blank.
See Also
