功率效率和频谱效率一般不能两全齐美。
Power efficiency and the general efficiency of spectrum-the United States can not be both loyal and filially pious.
同样，高的功率效率也要牺牲一定的频谱效率。
Similarly, the high power efficiency also needs to sacrifice certain frequency spectrum efficiency.
频谱资源是有限的，为了实现高速通信必须提高频谱效率。
In order to get high data rate communication, we must enhance frequency efficiency because mat frequency resource is limited.
研究采用可变速率传输的满负荷蜂窝无线通信系统的面积频谱效率。
The area spectral efficiency of fully loaded cellular radio communication systems with variable-rate transmission is investigated.
此方案可以提高光传输中的频谱效率，以及应用在全光逻辑器件领域。
The proposed scheme may be used for increasing spectral efficiency and all-optical logic device.
FQPS K是针对高频谱效率和高功率效率要求产生的一种调制方式。
FQPSK is a modulation technique that fits for high spectrum efficiency and high power efficiency request.
不需要大量计算，ERQ可以通过最佳连续码率和功率适应提高频谱效率。
Without any exhaustive numerical search, the ERQ can increase the spectral efficiency with the optimal continuous rate and power adaptation.
它可以提供在同一区域，时间和频段高出小学和CR用户共存的频谱效率。
It can provide higher spectrum efficiency by coexistence of primary and CR users at the same region, time, and spectrum band.
相比原有协议，改进方案分别在频谱效率或传输可靠性方面有不同程度提升。
Compared with existing protocols, improved ones enjoy better performance in terms of spectral efficiency or transmission reliability, respectively.
通过比较不同频谱效率下的不同转发方式的中断率性能，选择合适的传输方法。
The proper forward method can be found by the comparison of the outage probability under different spectral efficiencies.
运用功率分配和空时编码技术可以在MIMO系统中提高频谱效率、改善系统性能。
Power Allocation(PA) and Space Time Codes(STC) are the key techniques of the Multiple-Input Multiple-Output(MIMO) to increase spectral efficiency and improve performance.
OFDMA的最大的优点是能够抵抗频率选择性衰落，同时能够有效地提高频谱效率。
The biggest merit of OFDMA is the ability to resist frequency - selective fading, simultaneously can raise the frequency spectrum efficiency effectively.
考虑反馈信道存在延时的实际情况，推导了系统在延时信道条件下的频谱效率表达式。
Considering the practical case of delayed feedback environment, the closed-form expressions of system spectral efficiency under delayed channel were derived.
为了提高分布式无线通信系统(DWCS)的频谱效率，提出了一种下行功率分配算法。
A downlink power allocation scheme was developed to improve the spectral efficiency of distributed wireless communication systems (DWCS).
传统的CDMA技术存在严重的多址干扰现象，使得信道的频谱效率不能达到最佳状态。
The traditional CDMA technology has serious multi address interference phenomenon, so the frequency spectrum efficiency of the channel can′t reach the optimal state.
在未来的宽带无线通信系统中，存在着两个严峻的挑战：无线信道的多径衰落和频谱效率。
There are two serious challenges in the future broadband wireless communication systems: multi-path fading in the wireless channel and spectral efficiency.
此外，我们分析了成功的CR用户的通信概率和证明的频谱效率可以大大提高我们的计划。
Furthermore, we analyze the successful communication probabilities of CR users and demonstrate that the spectrum efficiency can be considerably improved by our scheme.
它具有提高连接性能和能量效率、提高网络覆盖率、提高频谱效率、增加网络容量等优点。
It has increased connectivity and energy efficiency, improved network coverage, increased spectral efficiency and increased network capacity and so on.
MIMO中继技术结合了多天线系统和中继技术的优点，进一步提高了中继系统的频谱效率。
MIMO relay channels, which combines the multiple antenna system and the relay, can improve the spectral efficiency of relay network.
仿真结果表明，采用最佳协作比的功率分配算法能显著减少系统功率消耗和提高系统频谱效率。
Simulation results show that the performances of power consumption and achievable rate can be improved significantly by adopting the optimal cooperative level and power allocation.
本文对照频分多址和时分多址系统的频谱效率，阐述了码分多址系统提高系统容量的几项关键技术。
The author has described several key techniques for improving the capacity of CDMA digital celullar system, comparing to the spectral efficiency of FDMA and TDMA cellular system.
在物理层技术层面上，具有高频谱效率和功率效率，并能适应环境和业务变化的技术成为研究的热点。
From a physical layer aspect, those techniques feature high frequency and power efficiency, and are able to adapt to changing environments and services, will win in the long run.
纠错编码技术可以提高光码分多址系统的频谱效率，并可以抑制频谱效率随码长的增加而减小的特性。
Error correction coding is used to increase the spectral efficiency, and it can avoid the spectral decrease with the increase of the length.
当可用带宽在WDMA与OCDMA之间不同的分配情况下，研究了该混合系统的总用户数和频谱效率。
Total users and spectral efficiency are studied under different proportion of total available bandwidth that is allocated to OCDMA and WDMA.
仿真实验得到：频谱效率小于一定值的情况下，利用放大和网络编码转发方式的性能大大高于直接传输方式。
Simulation results indicate if the spectral efficiency is less than some certain value, the performance of amplify-forward and network coding forward are much better than that of direct transmission.
通过自然的符号叠加形成了编码约束关系，不仅大幅度的提高了系统的频谱效率，而且有效的提高了系统性能。
Based on the overlapped symbols which can achieve coding constrain, it can be improved frequency efficiency and system performance.
线性MMSE检测子的峰值频谱效率与发送天线数有关，随发送天线数的增加而减小，随接收天线数的增加而增大。
The peak spectral efficiency of MMSE detectors decreases as the number of transmission antennas increases and increases as the number of receiving antennas increases.
由于高速数据占用更宽的带宽，所以在调制制式上应该寻找一种适合于跳频通信特点的具有高频谱效率的调制方案。
Because high-speed data take up wide bandwidth, looking for one which have high efficiency modulation scheme and suitable for frequency hopping communication system is needed.
由于高速数据占用更宽的带宽，所以在调制制式上应该寻找一种适合于跳频通信特点的具有高频谱效率的调制方案。
Because high-speed data take up wide bandwidth, looking for one which have high efficiency modulation scheme and suitable for frequency hopping communication system is needed.
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