Research And Implementation Of GSM Physical Layer Simulation Platform For Improved

Although the Chinese3G operators has matured over the years.sharing the market of around30%, but the vast majority of users still using2G mobile phone functions.2G has a great mass base,it’s network construction is very marure.Besides,GSM is the world’s most extensive coverage,with the most users (3.5billion) network standard.And operators who launche3G services are also choose to switch between GSM and3G mode. Thus, GSM still has great vitality.A GSM terminal tester can simulate GSM base stations and core network part feature, you can create simple business connection with the terminal, including:voice call services and emergency call services and supports GPRS and EDGE. This instrument has a lot of test functions, but there are many deficiencies. First, the terminal does not support the tester CS encryption and decryption functions, and data transmission services existing CS hollow mouth among almost all in the context of encrypted proceed. Secondly, the tester only supports full-rate business in the voice channel, the cell capacity nervous when you can not switch to the half-rate traffic to improve cell capacity.Furthermore, in terms of the physical channel,it only supports a few meter stage traffic channel basis functions, the terminal can not meet the test requirements for the physical channel rates. Finally,there are also limitations in the channel combinations of the terminal tester, and it is unable to meet the various channel flexible configuration requirements. In recent years, these shortcomings has little impact on the users, but with improved technology and GSM terminal function, more and more users tend to function better instrument.Currently, perfect GSM terminal test instruments are produced in foreign or joint ventures abroad, such as Datang PCT cascade with Agilent instruments, domestic GSM terminal test instrument function is not perfect these issues are key issues currently restricting terminal instrument function, so improve GSM physical layer simulation platform is important for terminal test instrumentation applications.This paper focuses on the design and verification of these issues. The main contents include four aspects:Encryption and decryption in the CS domain, the design and commissioning of the uplink and downlink voice channels and its subsidiary channel encryption and decryption process, as well as the upper and interfaces. The new commercial terminal test instruments also have included this feature.Half rate speech channel carries, the added voice channel uplink, including mapping half rate coding and half-rate channel multiframe. After several rounds of testing, this module has also been used in commercial test instruments.The rate of the physical channel, the improvement is achieved relevant. The main design rate encoding process for each channel, and its validation.In support of various combinations of channels, the main frame is designed mapping process more complex combinations of channels.Currently CS domain encryption and half-rate voice service modules have been applied to new commercial terminal test instruments.