Page 210 - From GMS to LTE

196 From GSM to LTE-Advanced Pro and 5G

Table 3.7 Spreading code sets and maximum resulting speed of different E‐DCH categories.

Modulation/ Maximum E‐DPDCH set of Maximum transport Maximum
Category dual‐cell the mobile device category block size for a TTI speed (Mbit/s)

2 QPSK 2 × SF‐4 14.592 bits (10 ms) 1.5
6 QPSK 2 × SF‐2 + 2 × SF‐2 20.000 bits (10 ms) 2.0
6 QPSK 2 × SF‐4 + 2 × SF‐2 11.484 bits (2 ms) 5.7
7 16‐QAM 2 × SF‐2 + 2 × SF‐2 22.996 bits (2 ms) 11.5

block sizes, as more bits are used for redundancy purposes. In addition, the Node‐B can
also restrict the maximum power to be used by the mobile device, as described above,
to distribute the available uplink capacity of the cell among the different active users.
In practice, most devices on the market today are E‐DCH category 6, capable of a
theoretical maximum uplink data throughput of 5.76 Mbit/s. Under good radio condi-
tions and when close to a base station, uplink speeds of 3–4 Mbit/s can be reached.

3.12 Radio and Core Network Enhancements: CPC
and One Tunnel

While the evolution of wireless networks mainly focuses on increasing datarates, other
factors such as reducing power consumption and increasing efficiency of the core net-
work architecture are also very important to keep the overall system viable. Starting
with 3GPP Release 7, a number of enhancements were specified in that direction – CPC
and One Tunnel.
CPC is a package of features to improve the handling of mobile subscribers while they
have a packet connection established, that is, while they have an IP address assigned.
Taken together, the features have the following benefits:
Reduction of power consumption;
●
Reduction of the number of state changes;
●
Minimization of delays between state changes;
●
Reduction of signaling overhead;
●
An increase in the number of mobile devices per cell that can be served simultaneously.
●
CPC does not introduce revolutionary new features. Instead, already existing features
are modified to achieve the desired results. 3GPP TR 25.903 [21] gives an overview of
the proposed changes and the following descriptions refer to the chapters in the docu-
ment that have been selected for implementation.

3.12.1 A New Uplink Control Channel Slot Format
While a connection is established between the network and a mobile device, several
channels are used simultaneously. This is because it is not only user data which is being
sent but also control information to keep the link established, to control transmit
power and so on. Currently, the Uplink Dedicated Control Channel (UL DPCCH) is