DL - 4G Americas

enables the base station to schedule HSDPA transmissions on up to four 5 MHz carriers simultaneously.
With the highest modulation scheme (64 QAM) and 2X2 downlink MIMO configured on all downlink
carriers this enables a peak data rate of 168 Mbps. However, besides doubling the peak data rate, 4C-
HSDPA operation will also double end-user data rates (burst rates) for a typical bursty traffic model when
compared to Rel-9 DC-HSDPA with MIMO.
The performance gain from multi-carrier operation is based on the resource pooling principle. 119 If multiple
downlink carriers are pooled an increased spectrum utilization efficiency can be achieved since the
probability of having unused resources reduces. This phenomenon is sometimes also referred to
“trunking efficiency.” It is interesting to note that in a system using 4X5 MHz carriers (but where only
single-carrier operation and load balancing are supported), 4C-HSDPA will yield a fourfold increase in
120 121
both peak and end-user data rates.
For 4C-HSDPA the configured system can be spread over two frequency bands. Similarly as in Rel-9 DB-
DC-HSDPA operation the following band combinations are supported (one for each ITU region): 122
� Band I (2100 MHz) and Band VIII (900 MHz): Two or three 5 MHz carriers can be configured in
Band I simultaneously as one 5 MHz carrier is configured in Band VIII
� Band II (1900 MHz) and Band IV (2100/1700 MHz): One or two 5 MHz carriers are configured in
Band II simultaneously as one or two 5 MHz carriers are configured in Band IV
� Band I (2100 MHz) and Band V (850 MHz): One or two 5 MHz carriers are configured in Band I
simultaneously as one or two 5 MHz carriers are configured in Band V
In addition to these dual-band configurations, it is also possible to configure three adjacent carriers in
Band I (2100 MHz) only (i.e. without configuring any carriers in another frequency band). The different
configurations for 4C-HSDPA in Rel-10 are illustrated in Figure 7.7. Introduction of additional band
combinations can be done in a release-independent manner.
119
D. Wischik, M. Handley, M. Bagnulo Braun, The Resource Sharing Principle, ACM SIGCOMM Computer Communication
Review, Vol 38, No 5, October, 2008.
120
3GPP Tdoc R1-091082, RAN1 findings of the UTRA Multi-Carrier Evolution study.
121
K. Johansson et al, Multi.Carrier HSPA Evolution, In Proceedings of VTC spring, 2009.
122
3GPP Tdoc R4-103975, Introduction of frequency bands for 4C-HSDPA, Ericsson, RAN4 Adhc meeting, Xian, China, October
11th – 15th, 2010.
www.4gamericas.org February 2011 Page 63