Testing TD-LTE with real world test technologies: Page 7 of 7

July 24, 2012 //By Erik Org, Azimuth Systems
Many wireless data networks were initially designed to offer symmetrical data capacities as the original killer wireless application, voice, required equal capacity for both uplink and downlink. Spectrum blocks were licensed and auctioned as paired spectrum suitable for Frequency Division Duplexing (FDD) protocols, which served carriers and subscribers well when voice was the primary application.
to a single resource block per unit time irrespective of the max capacity of TD-LTE or FDD LTE.

Verification of this performance can be accomplished using a variable AWGN noise source. AWGN noise is a good approximation of the noise seen by a device due to other sectors/cells in the vicinity of the terminal device.

Conclusion

The rising demand for wireless broadband data is driving the adoption of TD-LTE around the globe. With TD-LTE, the allocation of bandwidth can be modified by adjusting the scheduling of uplink and downlink transmissions on a single channel depending on the particular needs of the network. This enables carriers to operate LTE networks at a higher level of utilization, but the protocol poses a unique challenge to equipment design as it requires that both the uplink and downlink paths be balanced in order to correctly emulate a bidirectional connection.

TD-LTE testing must consider test equipment dynamic range, phase and amplitude balancing, and bidirectionality in order to model TD-LTE deployment scenarios including beamforming. To ensure excellent “real world” test of TD-LTE devices and systems, channel emulators can be chosen that both meet the aforementioned requirements and which also provide appropriate automation and channel models that help bridge the field and the lab and enable effective replication of real world conditions in the lab. One good example of such a channel emulator is Azimuth Systems’ ACE MX MIMO Channel Emulator. The ACE MX channel emulator is designed to easily support bidirectional testing and because it include internal isolators and circulators, is delivered to customers with phase and amplitude balanced channels — which ensures that regardless of the customer’s testbed, Azimuth’s real world solutions deliver excellent performance for real world TD-LTE testing.

Design category: