WINNER II pdf - Final Report - Cept

WINNER II D1.1.2 V1.2
5.6 Approximation of Channel Models
WINNER Generic model is aimed to be applicable for many different simulations and to cover high
number of scenarios with several combinations of large-scale and small-scale parameters. Generic
model is the most accurate model and is recommended to be used whenever possible. However, in
some simulations, channel model can be simplified (approximated) to reduce the simulation
complexity. It has to be done very carefully. When approximating the model, reality is reduced, and
the impact of the approximation has to be understood. The impact of the approximation depends on,
e.g., the transceiver system, algorithms, modulation, coding, multi-antenna technology, and required
accuracy of the simulation results. If someone is uncertain whether approximation affects on the
simulation results or not, it is better not to approximate. Therefore, the following approximation steps
can only be done by the simulation experts.
Firstly, we can approximate the model by assuming all the large scale parameters fixed to median
values. Furthermore, we can reduce the model by fixing the delays, but keep angles as random. The
third approximation can be done by freezing all propagation parameters to obtain so called Clustered
Delay Line (CDL) model. If, from a good reason, correlation model is desired, we can calculate
correlation matrices from the CDL model by fixing the antenna structure. Kronecker approach can
simplify the model even further, and finally, independent channels make the model very simple, but at
the same time very inaccurate. The approximation steps are shown below.
A) WINNER II Generic Model (D1.1.2)
B) Fixed large scale parameters
C) Constant delays, random angles (“CDL with random angles”)
D) WINNER II CDL Model (D1.1.2)
E) Tapped Delay Line model (delays are taken from CDL) with MIMO Correlation Matrix
F) Tapped Delay Line model with TX and RX Correlation Matrix, MIMO correlation is
obtained via Kronecker product.
G) Tapped Delay Line model, zero correlation between MIMO channels.
Page 60 (82)