The Research Of Power De-Rating And Testing Method Of TD-HSPA UE

As one of the main technologies of 3G, TD-SCDMA achieves the time division through the separation of time slots of up and down, which is especially suit for asymmetric services, such as packet data service. In order to achieve faster data transmission rate to get a better experience for users, the standard organization 3GPP introduced HSDPA technology in the specification of Release 5, and it greatly enhanced the downlink transmission rate; and then HSUPA was also introduced in Release 6, which allows to provide a data rate up to 2.2Mbps/s and 2.8Mbps/s respectively for up and down. In order to achieve this high-rate requirement, HSUPA introduced enhanced uplink transmission channel E-DCH and a series of key technologies that are used to improve the uplink transmission rate, including:Adaptive Modulation and Coding (AMC), fast hybrid automatic retransmission request (HARQ) and fast scheduling of uplink packet based on the NodeB. Then AMC introduced the high-order modulation 16QAM to realize the adaptive change of modulation type and transmission rate operated by UE base on the data transmission environment, which also will makes some negative influences on the peer value and the test method of maximum output power.16QAM can have a transmission rate twice of QPSK modulation, but it also will increase the PAR of signals which requires a more strict demand of power amplifier's linearity, resulting in additional interference out of band and directly affecting the performance of signal reception and demodulation. This paper analyzes several factors impacting the PAR value of signal, and then proposes the corresponding solutions, including modulation type with a lower PAR, PAR suppression technology, and linearization techniques of power amplifier.Bases on the theorem analysis of power amplifier linearization technology, the paper proposes a power de-rating solution that can be applied in TD-HSPA UE. With the simulation platform combining Matlab and ADS, the solution simulates the data processes in physical layer, such as encoding, modulation, spreading, scrambling, and transmitting. And the paper collects the PAR and other related parameters of emission signals and the actual testing results of commercial UE, and calculates the specific value that a TD-HSPA UE need to back off. Then the paper further verifies the factors that impacting the PAR value of LTE UE.In addition, the paper analyzes the problem that the existing testing method of maximum output power in 3GPP specification will cause a failure in case of 16QAM and AMC technology, and proposes a new testing method that uses the E-TFCI value as a testing indicator.