Page 155 - From GMS to LTE

Universal Mobile Telecommunications System (UMTS) and High-Speed Packet Access (HSPA) 141

UE Node-B RNC

Preamble
PRACH

Preamble (higher power)
PRACH
Acquisition indication
AICH
RRC: connection setup req. RRC: Connection setup req.
PRACH

NBAP: RL-setup
NBAP: RL-setup response

Iub bearer establishment
FP: downlink synch.

FP: uplink synch.

RRC: connection setup RRC: connection setup
FACH
RRC: conn. setup complete RRC: conn. setup complete
DCCH
Figure 3.14 Initial network access procedure (RRC connection setup) as described in 3GPP TS
25.931 [14].

inform the network about all optional features such as HSDPA parameters, HSUPA
parameters, dual‐carrier operation support and many other features that it supports.
This has become very important as practically all features that were specified in subsequent
3GPP Release versions are optional and hence the network cannot assume support
for them on the mobile device’s side. The network stores this information and makes
use of it later on when it needs to decide on how to configure the channels to the
mobile device.
After this basic procedure, the mobile device can then proceed to establish a higher‐
layer connection between itself and the core network to request the establishment of a
phone call or data connection (PDP context). A number of these scenarios are described
in Section 3.8.

3.4.6 The Uu Protocol Stack
UMTS uses channels on the air interface as was shown in the previous paragraph. As on
any interface, several protocol layers are used for encapsulating the data and sending it
to the correct recipient. In UMTS Release 99 the RNC is responsible for all protocol