Transmitter System Analysis and Design

Abstract

Chapter 5 kHz is the proper bandwidth for its transmission power measurement in the frequency domain. The main lobes of CDMA and GSM signal spectra are given in Section 2. 4.4.3, Fig. 2.35, and Section 2.4.4.2, Fig. 2.33.The maximum output power of a mobile transmitter will affect the overall wireless system performance, such as cell size and capacity, and the mobile station power consumption as well. It is well defined in all the wireless communication systems and is generally classified based on power levels and operating frequency bands. For the GSM system, in the 900 MHz band, the nominal maximum output powers of power class 2, 3, 4, and 5 are 39, 37, 33, and 29 dBm, respectively, but in the 1800 MHz band, the nominal maximum output powers of power class 1,2, and 3, are respectively 30, 24, and 36 dBm [2]. For the WCDMA system, in the UMT (2.0 GHz) frequency band, the nominal maximum output powers of power class 1 to 4 are 33, 27, 24 and 21 dBm, respectively [I]. In the CDMA system, the maximum output power is defined slightly different from the GSM and the WCDMA systems, and there lower and upper limits of the maximum output power are used instead of the nominal value [3]. These limits for the 800 MHz Cellular band and 1900 MHz PCS band CDMA mobile transmitters are 23 and 30 dBm for their popularly used power classes 3 and 2, respectively. However, the most commonly used maximum transmission powers in the practical mobile transmitter design of various wireless communication systems are presented in Section 3.1.3.2, Table 3.2. In reality, the maximum output power of a mobile transmitter might be also limited by compromising transmission power within the tolerance range for a better transmitter linearity and/or for meeting requirements of the spec@ absorption rate (SAR) * [4]. Modulation Accuracy Error Vector Magnitude E VM and Waveform Quality Factor pModulation accuracy is one of the key parameters for the wireless communication transmitters. The modulation accuracy is represented by error vector of modulation, which is the difference between the actual symbol location and the theoretical symbol location on the modulation vector constellation diagram. This may be better explained through an example. In the CDMA reverse link, offset QPSK (OQPSK) modulation is * SAR is used to measure the amount of RF power that a mobile station through its antenna delivers to the human body.