CAJ | 학술논문

为提高系统容量,提出了一种基于无碰撞区(NHZ)跳频序列的两级FFH/MFSK系统(称为NHZ/FFH系统).系统中全体用户被分成若干组,每组分配一个互不相同的NHZ跳频序列.由于NHZ跳频序列的汉明互相关在NHZ内等于0,只要用户间相对延迟不超过无碰撞区,就可以消除组间用户的干扰,多址干扰只来源于同一组内的用户.通过采用适于异步系统的多用户检测器,可以进一步提高系统的检测性能,且多用户检测器的规模和复杂度只与组内用户数有关.结合系统模型进行了干扰分析和仿真研究,结果表明,与现有MS/FFH系统相比,在相同的信道条件下,对于相同的误码率级别,NHZ/FFH系统支持的用户数多.
위제고계통용량,제출료일충기우무팽당구(NHZ)도빈서렬적량급FFH/MFSK계통(칭위NHZ/FFH계통).계통중전체용호피분성약간조,매조분배일개호불상동적NHZ도빈서렬.유우NHZ도빈서렬적한명호상관재NHZ내등우0,지요용호간상대연지불초과무팽당구,취가이소제조간용호적간우,다지간우지래원우동일조내적용호.통과채용괄우이보계통적다용호검측기,가이진일보제고계통적검측성능,차다용호검측기적규모화복잡도지여조내용호수유관.결합계통모형진행료간우분석화방진연구,결과표명,여현유MS/FFH계통상비,재상동적신도조건하,대우상동적오마솔급별,NHZ/FFH계통지지적용호수다.
To improve system capacity,a two-stage FFH/MFSK(fast frequency hopping/multilevel frequency-shift-keying)system based on frequency hopping sequence with no-hit zone(NHZ),named as NHZ/FFH system,was proposed.In this system,users are divided into a number of groups,and each group is assigned a unique NHZ FH(frequency hopping)sequence.Because the cross-correlations of NHZ FH sequences are equal to zero within no-hit zone,the multiple-access interference (MAI)between users of different groups can be eliminated as long as their relative delays do not exceed the no-hit gone.Therefore,MAI is only imposed on users belonging to the same user group.Furthermore.the muhiuser detection scheme used in an asynchronous system is utilized to improve thedetection performance,and the size and complexity of the multiuser detector are only decided by the number of users within a group.Interference analysis and simulation were carried out based on the system model.The simulation results show that compared with the existing MS/FFH system,the number of users supposed by the proposed NHZ/FFH system is great for the same BER(bit error rate)level under the same channel condition.