GSM Multi-band Mobile Terminal Radio Frequency Study

GSM system has more than 20 year history. GSM phone is also very popular in china before about 10 years ago. In 2004, the domestic brand phone have 50% market share, but in 2005, the market share is sharply decreased to 30%. One of the reason is our domestic brand company have not core technology, such as BB chip, Protocol, RF technology. These companys directly used the solution that foreign vendor given, the quality can't be controled by the themselves, so the market share is decreased.Although the RF technology is developed too years, but cost and quality is always concerned by the end of customer. In 2004, the GSM association also asked the industry for lower than 20$ phone. This requirement pushed the RF technoloy continuing to improve and innovate. So this paper Study the RF transceiver based the GSM air interface character and the optimized solution is proposed. The paper analyzes three sorts transmitter, IF/RF up-conversion, Zero IF up-conversion and OPLL up-conversion. Also three sort receiver, superheterodyne, Zero IF and Low IF receiver. The OPLL up-conversion transimitter and Low IF receiver is best choice from current technology, because the lower cost, and easy to get high performance.Accoding to GSM specification [4], come out the the transimitter and receiver sub-module design requirements. The followe key issues is covered, power consumption,power control,frequency and phase error,power vs.time mask,spurs,noise figure,dynamic range,cochannel and adjacent channel interfer,blocking,intermodulation and PLL phase noise.A high performance and low cost engineering solution is also proposed. This solution use Low IF receiver and OPLL transimitter. The solution is met the RF sub-module requirement, have the high intergration and lower cost advantage.