User Manual

ArchitectureNortel Networks Confidential 3–37
S8000/S8002/S8006 BTS Reference Manual
Radio resources management (radio level 3)
Radio level 3 provides the following functions:
level 2 management on the common channels
control of level 2 functions on dedicated channels
activation of the common channels
organization of the Common Control CHannel (CCCH), including chaining and
repetition of paging messages and transmission of dedicated channel allocation
messages
activation or deactivation of dedicated channels, implementation of encryption
and channel mode changes
providing SPU processors with system information on the SAACH and BCCH
channels
detection of ”random access” and ”handover access”
detection of radio link attenuation (monitoring of the upstream SACCH
channel), verifiable by the OMC
sending of the mobile transmission power change
Radio measurements management (level 3 radio)
This provides the following functions:
return of interference measurements carried out by the SPU processors on the
inactive dedicated channels and transmission of these measurements to the
AMNU
concatenation of measurements made by the SPUs on the active dedicated
channels and those transferred by the mobile over the same period
Operation & maintenance functions (O&M)
These functions provide configuration and deconfiguration of the time slots and
frequency hopping functions.
3.4.1.2 DCU8 unit
The DCU8 unit consists of two signaling processing chains, A and B, as shown in
Figure 3–11. Each chain handles four calls in full–rate voice mode and eight calls
in half–rate voice mode. Chain A and chain B are connected to a subassembly, the
BB_FILT ASIC, which is the interface with the radio part and filters reception
samples before sending them to the two chains. A second subassembly, the CHIF,
which is associated with the BB_FILT ASIC, calculates encryption and decryption
masks.
Chain A processes even radio reception time slots and odd radio transmission time
slots. Conversely, chain B processes odd radio reception time slots and even radio
transmission time slots.