cylxl 2007-1-7 14:33
问一个关于ＩＥＥＥ８０２．１６Ｅ里的问题
wimax ＰＨＹ层中用到了ＯＦＤＭ技术，８０２．１６Ｅ标准规定
8.4.2 OFDMA symbol description, symbol parameters and transmitted signal
8.4.2.3 Primitive parameters
Change this subclause as indicated:
The following four primitive parameters characterize the OFDMA symbol:
— BW: This is the nominal channel bandwidth.
— Nused: Number of used subcarriers (which includes the DC subcarrier).
— n: Sampling factor. This parameter, in conjunction with BW and Nused determines the subcarrier
spacing, and the useful symbol time. [u]This value is set to 8/7 as follows: for channel bandwidths that
are a multiple of 1.75 MHz then n = 8/7 else for channel bandwidths that are a multiple of any of
1.25, 1.5, 2 or 2.75 MHz then n = 28/25 else for channel bandwidths not otherwise specified then
n = 8/7. [/u]— G: This is the ratio of CP time to “useful” time. The following values shall be supported: 1/32, 1/16,
1/8, and 1/4.
有谁知道为什么采样因子Ｎ要设为８／７或２８／２５ ？
请高手指教，非常感谢！！