单项选择题
Which cell pattern is recommended for use with frequency hopping?（）
A. 4/12 B. 3/9 C. 7/21 D. 7/7 E. None of these
单项选择题 What does Grade of Service (GoS) mean? （）
单项选择题 What type of interference is produced by other transmitters on the same frequency? （）
单项选择题 Which unit is used for measuring traffic? （）
