1. For QPSK, each PRB pair can carry 252 bits (2*126), so 300 bits information needs at least two PRB pairs. These PRB pairs can be schedule in the frequency domain (PRB bundling) or in the time domain (TTI bundling). Both cases are considered as following to calculate the system capacity. To gurantee the QoS of VoIP, packet error rate of 1% is assumed in this paper. The SNR decoding threshold (S/N)thand Eb/N0decoding thresholds for 1% packet error rate are abtained by MATLAB simulations for different number of bundled PRB pairs or TTIs. The results for both downlink and uplink are shown in Fig. 5, and will be used forthesystem capacitycalculation. 2 3 4 5 6 7 8 -5 -4 -3 -2 -1 0 1 2 3 4
2. If NpPRB pairs are used within 1 TTI, the bandwidth of the VoIP link is B = Np* 180KHz. If the number of VoIPcarriers that can be supported is denoted as Nc, the EIRP for one carrier is 75 - 10lgNc,thenthereceive SNRattheuser terminalcanbeexpressed as ( ) ( )
3. This work is supported by China's 863 Project (2012AA01A502), National Basic Research Program of China (2012CB316000), International Science and Technology Cooperation Program (2012DFG12010), Key grant Project of Chinese Ministry of Education (No.313005), and Sino-Japan Joint Fund "Key Technique Research for GSS Integrated Mobile SatelliteCommunications".