Mobile communications networks are moving to the long term evolution (LTE) standards defined by the Third Generation Partnership Project (3GPP). The LTE physical layer, which provides physical layer communications between user equipment (UE), such as mobile handsets, and evolved node Bs (eNodeBs) is defined in 3GPP TS 36.201 and TS 36.211-216. The LTE physical layer provides modulation, physical channels, channel coding, and other aspects of physical layer communications between a UE and an eNodeB.
Before LTE network equipment, such as an eNodeB, can be placed into service, the equipment must be tested under operational or simulated operational conditions. For example, in operation, an eNodeB is required to handle simultaneous communications from multiple UEs. Accordingly, it is desirable for LTE test equipment to simulate multiple UE devices, while satisfying the timing requirements of the above-referenced LTE physical layer standards. LTE signal processing in LTE test equipment typically involves, at a high level, the receiving of an LTE signal from a single carrier by one or more antennas at the multi-UE simulator. The LTE signal is then forwarded to a symbol processing module (e.g., a field programmable gate array) for processing. The processed LTE signal is then sent to a resource de-mapping engine prior to being directed to one or more channel processors.
Although the above signal processing methodology functions correctly for current LTE communication systems utilizing a single carrier, this technique may be incompatible with future communication systems (e.g., LTE-Advanced) that utilize multiple-carrier technology, such as carrier aggregation. As used herein, carrier aggregation refers to using multiple different signal carriers in the same or separate frequency bands to increase the transmission bandwidth for a single downlink signal. To accommodate the reception of multiple carriers, the UE must also be equipped with additional antennas. However, as the number of carriers and the number of antennas to be utilized increase, the real-time processing resource demands attain a level where the typical single downlink signal chain (e.g., a receive signal chain) implementation is incapable of performing the necessary signal processing within the allotted processing time window. For example, the time constraints placed on the symbol processing portion of the downlink signal chain create a bottleneck in the overall process. Specifically, symbol processing includes a number of processing task modules, each of which is allocated a limited amount of time (e.g., 1 Symbol Time that is equal to 1/14 milliseconds) to complete its designated processing task. Although such allocated time is sufficient to process an LTE signal from a single carrier, the symbol processing module has difficulty or is incapable of processing an LTE signal received via multiple carriers (e.g., carrier aggregation) using the current downlink signal chain methodology for processing a signal received on a single carrier.
Accordingly, in light of these difficulties, there exist a need for methods, systems, and computer readable media for utilizing adaptive symbol processing in a multi-UE simulator.