发布时间 : 星期一 文章KDB 662911 多天线讲义-FCC认证更新完毕开始阅读8f1edeafa1116c175f0e7cd184254b35eefd1ab7
as determined by the “measure and sum the spectra” technique, is at least X dB below the total transmit power; alternatively, compliance may be demonstrated by confirming that the maximum out-of-band emission on each individual output is at least X dB below the maximum transmit power on that output.
Emission limits specified as X + 10 log(P) dB below the transmit power (where P is the transmit power) are absolute limits and are not considered “relative limits” for purposes of this guidance. Outof-band and spurious emissions must be tested against absolute limits using techniques described in section a) above.
当针对相对发射限制测试带外和杂散发射时，可以单独对每个输出执行测试，而不求和或增加10个对数（N）
如果测量是相对于单个输出上的带内发射进行的。
例如，如果规则规定在100kHz带宽中的带外发射必须比包含最高功率的带内100kHz带宽低至少20dB，则可以通过确认最大总输出功率带外发射比最大总带内PSD低至少20 dB，如在这两种情况下通过“测量和求和频谱”技术所确定的;或者，可以通过确认每个单独输出上的最大带外发射比该输出上的最大带内PSD（在100kHz带宽中）低至少20dB来证明顺应性。类似地，如果规则规定1MHz带宽中的带外发射必须至少比发射功率低X dB（其中X不随发射功率而变化），则可以通过确认最大总输出 - 由“测量和总和频谱”技术确定的带外发射至少比总发射功率低X dB;或者，可以通过确认每个单独输出上的最大带外发射比该输出上的最大发射功率低至少X dB来证明顺应性。
指定为低于发射功率X + 10 log（P）dB的发射限值（其中P是发射功率）是绝对限值，为本指南的目的不被认为是“相对限值”。带外和杂散发射必须使用上述a）节中描述的技术针对绝对限制进行测试。
F) GUIDANCE ON DIRECTIONAL GAIN CALCULATIONS 定向增益计算
Some rule parts define a limit on output power or power spectral density that is a function of the directional gain of the antenna system. There may also be cases in which conducted measurements are combined with directional antenna gain to determine compliance with radiated limits. In such cases, the effect of array gain must be included in the calculation of overall directional antenna gain for devices that transmit on multiple outputs simultaneously in the same band, in the same or in overlapping frequency ranges.
有一些标准会定义：天线系统的定向增益的函数的输出功率或功率谱密度的限制。
还可能存在其中进行的测量与定向天线增益组合以确定与辐射限制的符合性的情况。
在这种情况下，阵列增益的影响必须包括在针对在相同频带中，在相同或重叠的频率范围中同时在多个输出上发射的设备的总定向天线增益的计算中。
Array gain results when the signals transmitted on different antennas are positively correlated when viewed from a specific direction. In most cases, beamforming systems attempt to achieve 100 percent correlation between the transmitted signals when viewed from the intended beam direction, though actual correlation may be slightly lower. A transmitter that transmits correlated signals from its multiple antennas has the potential to create array gain even when that is not the intent. 当从特定方向观看时，在不同天线上发射的信号是正相关的时，得到阵列增益。
在大多数情况下，当从预期波束方向观察时，波束成形系统尝试实现发射信号之间的100％相关，但实际相关可能略低。
从其多个天线发射相关信号的发射机具有产生阵列增益的潜力，即使这不是意图。
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For simplicity, the guidance presented here categorizes transmissions as correlated (i.e., correlation exists between the signals on at least two antennas) or completely uncorrelated. Unless the transmitted signals are categorized as completely uncorrelated based on the guidance provided below, the signals must be considered correlated for the purposes of computing directional gain. In the case of correlated signals, array gain will be computed based on 100 percent correlation even if the actual correlation is lower except in certain cases involving cyclic delay diversity or multiple spatial streams.
为了简单起见，这里给出的指导将传输分类为相关的（即，在至少两个天线上的信号之间存在相关）或完全不相关。
除非基于以下提供的指导，所发送的信号被分类为完全不相关的，否则为了计算定向增益的目的，信号必须被认为是相关的。
在相关信号的情况下，将基于100％相关性来计算阵列增益，即使实际相关性较低，除了在涉及循环延迟分集或多个空间流的某些情况下。
1) Categorization as Correlated or Completely Uncorrelated分类：相关或完全不相关 For the purposes of this guidance, transmitter output signals are considered correlated if any of the following are true:
以下情况被视为是相关性的
?
?
? The operating mode combines correlated techniques with uncorrelated techniques.
·在给定符号周期中，即使具有不同的编码或相移，从两个或更多个天线发送相同的数字数据;
?两个发射信号之间的相关性存在于任何频率和时间延迟; 或者多个发射器输出用于在给定方向或给定接收器聚焦能量;
?操作模式将相关技术与不相关技术相结合。
Otherwise, the output signals are considered completely uncorrelated.
否则就是无相关性的产品
Correlation between two transmitted signals exists at any frequency and time delay; or, ?
Multiple transmitter outputs serve to focus energy in a given direction or to a given receiver;
The same digital data are transmitted from two or more antennas in a given symbol period, even with different coding or phase shifts;
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Correlated signals include, but are not limited to, signals transmitted in any of the following modes: 以下产品均为相关性的
? Any transmit beamforming mode, whether fixed or adaptive (e.g., phased array modes,
closed loop MIMO modes, Transmitter Adaptive Antenna modes, Maximum Ratio Transmission (MRT) modes, and Statistical Eigen Beamforming (EBF) modes).
beamforming 模式
? Cyclic Delay Diversity (CDD) modes, also known as Cyclic Shift Diversity (CSD)
(including modes for 802.11n and later devices to communicate with legacy 802.11 devices). In CDD modes, the same digital data is carried by each transmit antenna, but with different cyclic delays. The signals are highly correlated at any one frequency, though not necessarily at zero time delay. In particular, correlations tend to be high over the bandwidths specified for in-band PSD measurements in FCC rule parts that require reductions in PSD when directional gain exceeds a threshold.
CDD/CSD
循环延迟分集（CDD）模式，也称为循环移位分集（CSD）（包括用于802.11n和以后的设备与传统802.11设备通信的模式）。
在CDD模式中，相同的数字数据由每个发射天线承载，但具有不同的循环延迟。 信号在任何一个频率处高度相关，但不一定是零时间延迟。
特别地，在定向增益超过阈值时需要减小PSD的FCC规则部分中，针对带内PSD测量而指定的带宽上的相关性趋向于高。
Completely uncorrelated signals include those transmitted in the following modes, if they are not combined with any correlated modes, such as beamforming:
? Space Time Block Codes (STBC) or Space Time Codes (STC) for which different digital
data is carried by each transmit antenna during any symbol period (e.g., WiMAX Matrix A [Alamouti coding]).
? Spatial Multiplexing MIMO (SM-MIMO), for which independent data streams are sent to
each transmit antenna (e.g., WiMAX Matrix B). WiMAX Matrix C, which adds diversity, also produces uncorrelated transmit signals.
The FCC Laboratory may consider adjustments to this guidance as new modes of operation are brought to its attention.
完全不相关的信号包括以下模式中传输的信号，如果它们不与任何相关模式组合，例如波束形成： ·在任何符号周期期间由每个发射天线承载不同数字数据的空时块码（STBC）或空时码（STC）（例如，WiMAX矩阵A [Alamouti编码]）。 ·空间复用MIMO（SM-MIMO），对于该空间复用MIMO，独立的数据流被发送到每个发射天线（例如，WiMAX矩阵B）。 添加分集的WiMAX Matrix C也产生不相关的发射信号。
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FCC实验室可以考虑对本指南进行调整，因为新的操作模式已引起注意
2) Directional Gain Calculations for In-Band Measurements带内测量的定向增益计算
a) Basic methodology with NANT transmit antennas, each with the same directional gain GANT
dBi, being driven by NANT transmitter outputs of equal power. Directional gain is to be computed as follows:
(i) If any transmit signals are correlated with each other, Directional
gain = GANT + 10 log(NANT) dBi
(ii) If all transmit signals are completely uncorrelated with each other,
Directional gain = GANT
a）具有N发射天线的基本方法，每个具有相同的定向增益Gn dBi，由具有相等功率的N发射机输出驱动。 定向增益计算如下：
（i）如果任何发射信号彼此相关，则方向增益= Gn + 10log（N）dBi （ii）如果所有发射信号彼此完全不相关，则方向增益= Gn
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