METROPOLITAN AREA NETWORKS
Burst Profile Z
Burst Profile Y
DBPC stands for downlink burst profile change
RNG stands for ranging
REQ stands for request
The DL-MAP message defines usage of downlink and contains carrier-specific data.
The DL-MAP message is the first message in every frame and its decoding is time-critical,
typically done in hardware. Entries denote instants when the burst profile changes.
Uplink transmissions are invited transmissions and are in contention slots, which
include bandwidth requests. Transmissions are in initial ranging slots and are ranging
requests (RNG-REQs). The contention is resolved using truncated exponential back-
off. The bursts are defined by UIUCs (uplink interval usage codes). Transmissions are
allocated by the uplink-MAP message. All transmissions have synchronization pream-
ble. Ideally, all data from a single SS (subscriber station) is concatenated into a single
The uplink channel descriptor is sent regularly. It defines uplink profiles. All uplink
burst profiles are acquired. Burst profiles can be changed on the fly. The uplink channel
descriptor establishes association between UIUC and actual PHY parameters.
The uplink MAP message defines usage of the uplink and contains the "grants." Grants
are addressed to the subscriber station. The time is given in mini-slots, the unit of uplink
bandwidth allocation. There are 2
physical slots. In the 10- to 66-GHz band PHY, the
physical slot is 4 symbols long. The time is expressed as the arrival time at the BS
There are four classes of uplink service, which is a characteristic of the service flow.
1. Unsolicited grant services (UGS). This class is for constant bit-rate (CBR) and
CBR-like service flows (SFs) such as T1/E1.
2. Real-time polling services (rtPS)
For rt-VBR-like SFs such as MPEG video
3. Non-real-time polling services (nrtPS)