Propsim C8 provides a flexible platform for Multiple Input Multiple Output (MIMO) development and evaluation. With a maximum number of 16 independent fading channels the Propsim C8 MIMO Extension allows emulation of complex scenarios such as 4x4 MIMO within one device. More complex scenarios, for example multiuser MIMO scenarios, are supported by synchronising multiple units. Test case connections, correlative radio channel models and emulations are fast and easy to create with the Graphical User Interface.

MIMO Technology – New Aspects for Performance Testing
MIMO technologies utilize the impairments within the various different propagation paths to gain additional system performance, either as extended coverage or as higher data rates. The MIMO gain is based on the non-correlative
behaviour of independent transmission paths. In ideal conditions the parallel MIMO sub channels are uncorrelating
but propagation measurements have proven that this is not always the case in real-world. It is recommended to test the performance of the system under non-ideal conditions with several different levels of correlation between the parallel MIMO sub channels. As the system gain is affected heavily by the correlation between channels it is necessary to be able to emulate the correlation in the channel models accurately but also repeat the same test cases with same correlation behaviour. This correlation accuracy and repeatability is crucial for any performance test environment of
MIMO systems and essential in being able to discover the real performance of design under test.

Propsim C8 – Accurate MIMO Channel Emulator
The accuracy of parameters such as phase error between paths and channels, amplitude accuracy between paths and channels, correlation between channel models on different channels and accuracy of the calculated correlation matrices are important as they create the base for MIMO-gain. The integrated Propsim C8 multichannel emulator design is based on the mentioned MIMO-emulation and -modelling fundamentals and therefore it provides the best features and performance to carry out accurate and repeatable MIMO development testing. It features also support for usage of one RFLO signal for all channels to minimise phase noise affects for correlation accuracy and build in AWGN and interference generation capabilities to enable users to test MIMO systems under controlled interference conditions. The new MIMO extension supports up to 4x4 MIMO configurations. It is designed on the existing Propsim C8 emulator platform enabling upgrade path for existing emulators and supporting upgrade path from basic 2 channel configurations up to full 4x4 when needed.

Supports Any Wireless Technology
MIMO systems are being investigated for various different wireless standards ranging from WLAN / Wi-Fi and WiMAX to WCDMA, TD-SCDMA and B3G systems. With Propsim C8 supporting operating frequencies up to 6GHz and bandwidths up to 100MHz, the performance gain from MIMO can be evaluated for any wireless technology. Propsim C8 has Analog and Digital Baseband interfaces enabling testing of MIMO algorithms already when developing the baseband e.g. chipsets. The new Propsim C8 with MIMO Extension provides a versatile platform that is easily configured by user for different Tx- and Rx-antenna MIMO configurations. This provides users with a flexible solution for any MIMO technology development with different type of Tx and Rx antenna setups.

Propsim C8 provides versatile modelling tools for MIMO
MIMO channel models are being developed for different standards including 3GPP, 802.11, 802.16 and future 4G systems. Propsim C8 supports all known models already standardised or in pre-standardisation phase. The models under standardisation include 3GPP SCM and SMCE models for WCMDA-MIMO, 802.11n TGn models for WLAN MIMO and various proposal for WiMAX and 4G systems. The development and standardisation of the MIMO-models and modeling techniques is ongoing and new models are to be introduced. Elektrobit channel emulation platforms are designed to support any channel models and therefore the Propsim C8 emulator is future proof for new MIMO models.


Figure 2. Modeling correlative channels in Propsim C8 with Spatial Channel Modeling (SCM) approach

The Propsim C8 graphical user interface (GUI) allows users to create their own channel models with arbitrary complex correlations based on Tx and Rx antenna correlation matrices. This way the correlation between individual fading paths on different channels can be controlled accurately. This is also considered as the main stream in MIMO-modelling. The GUI-tool also supports Direction of Arrival (DoA) channel modeling for Antenna Array Systems (AAS). To enable modeling flexibility in Propsim C8 users can import channel models from other modeling sources e.g. MatLab. This provides user the possibility to model all fading effects e.g. Doppler spectra, amplitude distribution and correlation matrices freely. Propsim C8 offers as an option an easy to use channel modeling tool for generating 802.11n TGn standard compliant channel models. The emulator unit also includes wide variety of pre-defined standard channel models.