Page 192 - From GMS to LTE

178 From GSM to LTE-Advanced Pro and 5G

RNC HS-DSCH DCCH DTCH* Logical channels

DCH Transport channels

Node-B

Physical channels

UE ...
HS-PDSCH HS-SCCH DPDCH DPCCH
* Optional, e.g. for a
Shared Dedicated simultaneous voice
call
Figure 3.38 Simplified HSDPA channel overview in downlink direction.

DTCH DCCH DTCH* Logical channels
RNC (IP data) (RRC)

DCH Transport channels
Node-B

Physical channels

UE
DPCCH DPDCH DPCCH
(for HSDPA) (user data + RRC) (control of dedicated connection)
* Optional, e.g. for
a simultaneous
voice call
Figure 3.39 Simplified HSDPA channel overview in uplink direction.

to increase the transmission speed for a single subscriber by bundling several HS‐PDSCH,
where each uses a different code.
Each HS‐PDSCH uses a spreading factor length of 16, which means that in theory, up
to 15 simultaneous HS‐PDSCH channels can be used in a single cell. When reception
conditions permit, higher‐order modulation and coding can be used to increase the
transmission speed. In operational networks, the number of HS‐PDSCH channels
available per cell depends on the number of voice calls and circuit‐switched video calls
handled by the cell for other users in parallel, since these require a DCH. In practice,
many network operators use at least two 5 MHz channels per sector in areas of heavy