R&S
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CMW 500 WiMAX Applications
WiMAX TX Measurements
Operating Manual 1202.3986.32 – 03 371
In the simplest case, one UL frame contains a single UL-PUSC "permutation zone"
which is divided into several bursts. Each burst has its individual coding and
modulation scheme (burst profile). The bursts can be transmitted in parallel and can
vary in size.
The assignment of subcarriers to bursts is a two-stage process:
1. Mapping of subcarriers to logical sub-channels:" Zone Definition"
The UL channel is partitioned into "tiles", each consisting of 12 adjacent
subcarrier/symbol instances (which we will call "subcarriers" for simplicity). Four of the
subcarriers are configured as pilot subcarriers, the remaining 8 subcarriers are data
carriers.
To create a logical sub-channel (also termed a slot), the physical tiles are renumbered
(permutated) and combined. The permutation rule depends on the "Perm Base"
parameter; the number of tiles for each logical sub-channel is 6. Permutation of tiles
ensures that each sub-channel uses non-adjacent sub-carriers, which reduces the
impact of interferences and multipath fading on the transmission.
A segment is a group of sub-channels that is used for deploying a single instance of
the MAC. Segments are identified by their "Segment No" and "PRBS ID".
2. Assignment of sub-channels to bursts: "Map of Bursts"
The sub-channels (slots) provide an alternative description of the UL frame as a
rectangle in the sub-channel/time plane. A burst contains an integer number of sub-
channels and corresponds to a contiguous area within this UL frame. According to the
tile definition reported above, the number of symbols per UL sub-channel is equal to 3,
so the number of symbols in the burst must be an integer multiple of 3.
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