为了实现扩展的二元相移键控(EBPSK)调制的多载波传输,提出了一种基于时分的EBPSK多载波实现方式.首先,利用叠加原理,通过观察冲击滤波器的输出波形,分析了多路EBPSK信号间干扰的原因;然后,给出了消除信号间干扰的具体思路,即将临道信号相对延迟,使各路载波的判决区域在时间上区分开,避免判决区域的碰撞;最后,通过仿真,对比了不同时间保护间隔下基于时分的EBPSK多载波与单载波的误码率性能.仿真结果表明,时间保护间隔为0时干扰较大,多载波的误码率性能较差.在合适的时间保护间隔下,多载波的误码率性能几乎与单载波一致.基于时分的EBPSK多载波实现方式能够有效消除各路EBPSK信号间的干扰,使得多路EBPSK信号同时传输且误码率性能损失不明显.

In order to realize multi-carrier transmission of extended binary phase shift keying (EB-PSK)modulation,a realization method is proposed based on time-division.First,based on the su-perposition principle,the cause of interference among EBPSK multi-carrier signals is analyzed by ob-serving the output waveform of the impacting filter.Then,the detailed method for eliminating inter-nal channel interference is given;that is,the judgment areas of the EBPSK multi-carrier signals are separated by relatively delaying neighboring signals to avoid the collision of the judgment areas.Fi-nally,the bit error rate (BER)of the EBPSK multi-carrier based on time-division and that of the EBPSK single carrier are compared under different time guard intervals.The simulation results show that the internal channel interference is larger and the BER performance of EBPSK multi-carrier is worse when the time guard interval is zero.Under the proper time guard interval,the BER perform-ance of the EBPSK multi-carr

针对重叠码调制的正交频分复用(SCM-OFDM)系统在高速移动环境中,将产生复杂的载波间干扰和层间干扰问题,提出了一种用于SCM-OFDM系统在高速信道中的干扰估计和抵消算法。该算法利用译码器反馈的软信息,分别对载波间干扰和层间干扰进行估计和消除。仿真结果表明,提出的算法能够有效地改善SCM-OFDM系统在高速环境下的性能。

Superposition Coded Modulation-Orthogonal Frequency Division Multiplexing(SCM-OFDM)systems are prone to the problem of serious interference from multiple-layers and inter-carriers when mobile terminals are in a high speed environ-ment. To alleviate this problem, an interference estimation and cancellation algorithm is proposed for SCM-OFDM systems in high speed channels. In this algorithm, the Intercarrier Interference(ICI)and Multiple-Layer Interference(MLI)can be estimated and cancelled separately based on the soft information fed back from decoders. Simulation results show that the proposed algo-rithm can improve the performance of SCM-OFDM systems in the high speed movement.

针对异构网络存在小区间干扰的问题，提出了一种基于频域载波聚合的干扰协调管理机制。该机制将所有小区的用户分为中心用户和边缘用户，采用可降低干扰的信漏噪比（SENR）准则，动态调度用户和选择小区载波，并将每种小区载波选择方案对应一种调度用户分组的机制，即对小区的中心用户和边缘用户采用不同优先级，以此有效避免小区间的干扰，其中优先级采用比例公平和SLNR准则。仿真结果表明，由于在系统目标最大化时实现了频率复用增益和干扰消除增益间实现最佳的平衡，可有效取得系统流量的分流和总吞吐量的提升。

In order to minimize inter-cell interference in heterogeneous networks,a new interference coordination mechanism based on carrier aggregation is proposed. The proposed method first divides the users into center users and edge users,then uses the signal-to-leakage-plus-noise ratio(SLNR)criterion to schedule the different users across the cells to share the same carrier resources. As a result,the method selects cells and carriers dy-namically,and schedules users corresponding to each specific combination of carrier and cell. The scheduling method is based on modified PFS and SLNR criterion which gives different priority for center users and edge users. Simulation results show that the proposed scheme can realize the best tradeoff between the gain of fre-quency reuse and interference avoidance when maximizing the system objective,so as to effectively offload sys-tem flow from the Macro cell to Pico cell and improve system throughput.

在随钻声遥测技术中,周期性钻柱结构产生的多重回波极易造成严重的码间干扰和较高误码率,为此,根据钻柱信道的多径传输特性,基于短钻杆条件下多载波传输的实验分析,建立了多节钻杆与管箍的周期性信道有限差分模型。考虑地面噪声和信道内多径回波干扰,利用最小均方自适应均衡,基于"4钻杆-3管箍"信道结构进行了多载波调制性能仿真分析。仿真结果表明,与单载波PSK(Phase-Shift-Keying)调制相比,OFDM(Orthogonal Frequency Division Multiplexing)多载波调制可使误码率平均降低约50%;在非周期性结构下其传输性能受信道变化敏感,但相同条件下仍优于PSK调制,且通过子载波相位补偿可有效改善误码率、提高传输性能。

The multiple echoes caused by periodic structure of a drillstring in acoustic telemetry during drilling tend to lead to the serious intersymbol interference and high bit error rate. According to the multipath transmission characteristics of a drillstring,based on the multi-carrier acoustic transmission test analysis along a short drill pipe,a finite difference model for a periodic channel composed of multiple drill pipes and tool joints was established.Considering the ground surface noises and multipath echo interferences in the channel,a least mean square adaptive equalization method was introduced.Then,the multi-carrier modulation performance was simulated by using a drillstring structure with four drill pipes and three tool joints.The simulation results showed that the orthogonal frequency division multiplexing (OFDM)-based multi-carrier modulation can obtain a bit error rate (BER)which is 50 % less than that of the phase-shift-keying (PSK)modulation;although its transmission charat

为了对抗无线信道传输的多径效应和码间干扰(ISI),采用了SC?FDE(单载波频域均衡)技术.在系统仿真中,发送端发送连续的基于UW 的数据帧结构,通过多径瑞利信道和高斯白噪声信道,在接收端采用滑动窗原理先进行帧同步检测,后采用最小二乘(LS)算法进行频域均衡,获得系统的误码率曲线图,验证了单载波频域均衡技术具有对抗多径效应和码间干扰的特点.

The SC?FDE(single carrier transmission with frequency domain equalization) technology is used to overcome the channel multi?path effect and ISI(Inter?Symbol Interference) of the wireless broad band transport system. In the system simulation,the consecutive frames with ideal training sequences(UW)get through the channel compounded with the multipath Rayleigh fading channel and AWGN channel,and first the frame synchronization is solved by sliding window theory and then LS algorithm is adopted for frequency domain equalization in the receiver. Finally,the BER(bit error rate)of the scheme is got and the simulation result proves that the scheme has good performance in multi?path effect and ISI.