Cobham Wireless, a global leader in the provision of advanced wireless coverage and mobile communication systems, has announced that the industry-standard TM500 network test system now includes support for 256 QAM modulation – one of the key features of LTE-Advanced (LTE-A, also known as 4G) which is being introduced in 3GPP Release 12. The use of this modulation scheme in combination with carrier aggregation (CA) in the downlink, boosts data rates up to 600 Mbps and allows network operators to improve spectrum efficiency for mobile terminal devices under favourable operating conditions.
“We first demonstrated the TM500’s 256 QAM capability at this year’s Mobile World Congress, and this feature is now enabling our customers to validate the high-speed performance of their LTE-A networks,” said Ngwa Shusina, technical product manager at Cobham Wireless. “Increasing the modulation order to 256 QAM provides a 33% increase in LTE-A data rate compared with 64 QAM, and can be implemented when channel conditions are favourable and cells are sparsely populated.”
256 QAM used in conjunction with carrier aggregation and 2 layers MIMO enables theoretical data rates of up to 600 Mbps. This is particularly applicable to small cell deployments, where users are close to the base station and high signal-to-noise ratios can be achieved. 256 QAM is supported over multiple aggregated carriers, allowing complex mobility scenarios including a mixture of mobile terminals operating to different 3GPP Release standards. This is accompanied by enhanced mobility models to reflect the challenging operational and mobility scenarios that occur with higher modulation orders.
Downlink 256 QAM support is available as a software upgrade for existing TM500 customers. This gives infrastructure vendors the capability to validate networks under a range of realistic usage scenarios, and to determine where the use of the higher order modulation scheme will improve customer experience. The real world of mixed macrocell and small cell combinations provides a complex RF environment for validating the correct operation and performance of dynamically changing modulation schemes. The ability to create a realistic – yet controlled – environment, and to allow different levels of complexity and realism to be selected, is the key to rapid feature deployment. As 256 QAM is rolled out with LTE-A networks, the TM500 network test system will enable network operators to validate both the underlying feature performance and the impact upon end user experience using real data traffic applications.
