useful adj. 1.有用的,有益的,有效的,有帮助的。 2.〔俚语〕值得称赞的,精通…的 (at)。 make oneself generally useful 事事有用,事事帮得来忙 (He must make himself generally useful. 他可事事都干得来)。 a pretty useful performance 相当精采的演出。 His wife is very useful at cooking. 他的妻子很会做菜。 adv. -ly ,-ness n.
Unlike pilots which are used for estimation of channel and must waste some useful bandwidth , the ppss , whose power can be boosted 3db or 6db to suppress efficiently the additive noise , is useful data transmitted , thus efficiency of the ofdm has been increased 与用于做信道估计的导频符号不同, ppss传输的是有用的数据,因此提高了系统的带宽利用率, ppss的平均功率增加3db或6db可有效抑制信道的加性高斯噪声。