System Level Performance Analysis of Advanced Antenna ... - Centers

Introduction
In Release’99, there are two types of transport channels: dedicated transport channels
and common transport channels [27]. The only dedicated transport channel is the dedicated
channel (DCH). There are six types of common transport channels: broadcast channel (BCH),
forward access channel (FACH), paging channel (PCH), random access channel (RACH), UL
common packet channel (CPCH) and downlink shared channel (DSCH). Further explanations
for each channel can be found in [1], and detailed information about how these channels are
mapped onto the physical layer is given in [27] and illustrated in Figure 1.2. In order to
understand the rest of the thesis, only the DCH needs further explanation.
Transport channels Physical channels
BCH
FACH
PCH
RACH
DCH
DSCH
CPCH
Primary common control physical channel (PCCPCH)
Secondary common control physical channel (SCCPCH)
Physical random access channel (PRACH)
Dedicated physical data channel (DPDCH)
Dedicated physical control channel (DPCCH)
Physical downlink shared channel (PDSCH)
Physical common packet channel (PCPCH)
Synchronisation channel (SCH)
Common pilot channel (CPICH)
Acquisition indication channel (AICH)
Paging indication channel (PICH)
CPCH status indication channel (CSICH)
Collision detection/Channel assignment indicator channel
(CD/CA-ICH)
Figure 1.2: Mapping of transport channels onto physical channels (Release’99) [27].
One DCH is exclusively allocated to one UE. The DCH conveys all the information
intended for that UE coming from higher layers, including data for the actual service. It can
be used for both UL and DL, and supports CLPC with one power update per slot 2 , multi-code
operation, bit rate variations with one frame resolution, SHO and the use of AAs. With
spreading factor (SF) 4 and three parallel multi-codes, a DL DCH can carry approximately 2.8
Mbps when the coding rate equals ½ [27]. The same approximate bit rate can be obtained for
the UL with SF 4, three parallel multi-codes and a coding rate of ½.
All Release’99 transport channels are terminated at the RNC. Thus, retransmissions for
packet data are controlled by the Radio Link Control (RLC) functionality at the RNC.
2 The slot duration is 0.667 ms, and the radio frame duration is 10 ms, i.e. 15 slots [27].
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