Agilent 5991-3762EN Solutions for LTE-Advanced Manufacturing Test - Application Note c20140820 [16] free download

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Keysight Solutions for LTE-Advanced Manufacturing Test Understanding the Requirements for LTE-Advanced Carrier Aggregation Manufacturing Test Application Note Introduction Overview Carrier aggregation (CA), introduced in the 3GPP Release 10 standard, is an important new feature of LTE-Advanced. Carrier aggregation enables the combining of multiple LTE carriers into a larger, sin- glechannel bandwidth to increase data rates and throughput. For operators with limited or fragment- ed spectrum allocations, carrier aggregation is a way to keep pace with the growing data demands on their networks. A goal of LTE-Advanced is to preserve backward compatibility with earlier LTE releases. For that reason, CA in LTE-Advanced is based on the carriers first defined for 3 GPP Release 8. This allows existing LTE devices to continue operating properly but enables new devices to support the higher data throughput that CA makes possible. The LTE carriers defined in Release 8 are called component carriers (CCs). Component carriers can use any of the 3GPP-defined LTE bandwidths--1.4, 3, 5, 10, 15, or 20 MHz--and up to five CCs can be combined for a theoretical maximum of 100 MHz of bandwidth. Since most LTE-FDD operators today lack the spectrum to support the widest channels, they are ex- pected to use the 5 or 10 MHz bandwidths for carrier aggregation. In LTE-Advanced systems based on frequency division duplex (FDD), the number of CCs aggregated in the uplink must always be less than or equal to the number of aggregated downlink CCs. The carrier bandwidths can vary--for example, a 5 MHz carrier can be combined with a 10 MHz carrier--as this scenario is most likely to be fielded by operators. In systems based on time division duplex (TDD), both the downlink and uplink share the same chan- nel. As defined in Release 10, the number of aggregated CCs in a TDD system and the bandwidth of each CC must be the same for the downlink and the uplink. This definition changes in 3GPP Release 11, which introduces TDD support for different uplink and downlink configurations in each frequency band. Figure 1. A simplified view of carrier aggregation. Multiple LTE carriers are combined into a larger, single-channel bandwidth to increase data rates and throughput and to make best use of available spectrum. 03 | Keysight | Understanding the Requirements for LTE-Advanced Carrier Aggregation Manufacturing Test - Application Note Two types of carrier aggregation are defined for LTE-Advanced in Release 10: intra-band carrier aggregation and inter-band carrier aggregation. With intra-band CA, aggregated CCs occupy channels within a single LTE frequency band. These channels may be contig- uous (adjacent), non-contiguous, or both if more than three CCs are used (Figure 2). Som