KDB 662911 多天線講義-FCC認(rèn)證

1、 October 31, 2013 Emissions Testing of Transmitters with Multiple Outputs in the Same Band (e.g., MIMO, Smart Antenna, etc) 什么是MIMO?MIMO有哪些技術(shù)？MIMO(Multiple-Input Multiple-Output)技術(shù)指在發(fā)射端和接收端分別使用多個發(fā)射天線和接收天線，使信號通過發(fā)射端與接收端的多個天線傳送和接收，從而改善通信質(zhì)量。它能充分利用空間資源，通過多個天線實現(xiàn)多發(fā)多收，在不增加頻譜資源和天線發(fā)射功率的情況下，可以成倍的提高系統(tǒng)信道容量，顯示出明顯

2、的優(yōu)勢、被視為下一代移動通信的核心技術(shù)。MIMO技術(shù)的應(yīng)用上行傳輸對于R8/R9的LTE終端，主要配置為雙天線，但是采用單發(fā)雙收的工作模式。上行鏈路MIMO的工作方式主要包括以下幾種：單天線傳輸：采用上行單天線傳輸方式，使用固定天線發(fā)送（端口0）。開環(huán)發(fā)送天線選擇分集：采用上行單天線傳輸方式，終端選擇天線進行上行傳輸。閉環(huán)發(fā)送天線選擇分集：網(wǎng)絡(luò)側(cè)通過下行物理控制信道上承載的下行控制信息通知終端采用特定天線進行上行傳輸。上行MU-MIMO：網(wǎng)絡(luò)側(cè)能夠根據(jù)信道條件變化自適應(yīng)地選擇多個終端共享相同的時頻資源進行上行傳輸下行傳輸LTER8/R9版本中下行引入了8種MIMO傳輸模式，其中LTEFDD常用

3、的MIMO傳輸模式為模式1到模式6（TM1TM6），而模式7（TM7）和模式8（TM8）主要應(yīng)用于TDLTE系統(tǒng)中，下面是不同傳輸模式的簡要說明。模式1：單天線端口傳輸（端口0）。模式2：開環(huán)發(fā)射分集。模式3：大延遲CDD空間復(fù)用與開環(huán)發(fā)射分集自適應(yīng)。模式4：閉環(huán)空間復(fù)用與開環(huán)發(fā)射分集自適應(yīng)。模式5：多用戶MIMO與開環(huán)發(fā)射分集自適應(yīng)。模式6：單層閉環(huán)空間復(fù)用與開環(huán)發(fā)射分集自適應(yīng)。模式7：單流波束賦形（端口5）與開環(huán)發(fā)射分集或單天線端口傳輸（端口0）自適應(yīng)。模式8：雙流波束賦形（端口7和端口8）或單流波束賦形（端口7或端口8）與開環(huán)發(fā)射分集或單天線端口傳輸（端口0）自適應(yīng)。A) SCOPE T

4、his document provides guidance for measurement of conducted output emissions of devices or composite systems that employ a transmitter with multiple outputs in the same band or multiple transmitters operating in the same band, with the outputs occupying the same or overlapping frequency ranges. It a

5、pplies to EMC compliance measurements on devices and systems (including hosts with multiple modular transmitters) that transmit on multiple antennas simultaneously in the same or overlapping frequency ranges through a coordinated process. Examples include, but are not limited to, devices and systems

6、 employing beamforming or multiple-input and multiple-output (MIMO.) This guidance applies to both licensed and unlicensed devices wherever the FCC rules call for conducted output measurements or where conducted output measurements are combined with directional antenna gain to demonstrate compliance

7、 with a radiated limit. Guidance is provided for in-band, out-of-band, and spurious emission measurements. KDB 662911工作在同一頻段的多發(fā)設(shè)備處理方法，適用于如下測試項：帶內(nèi)發(fā)射帶外發(fā)射雜散發(fā)射1. 傳導(dǎo)輸出設(shè)備獨立設(shè)備多個輸出多個設(shè)備多個輸出2. 符合系統(tǒng)設(shè)備獨立設(shè)備多個輸出多個設(shè)備多個輸出For devices having two outputs driving a cross-polarized pair of antennas, see Attachment 66291

8、1 D02 of this publication for additional guidance. 對于具有水平極化天線對的雙輸出設(shè)備，請參閱KDB 662911 D02以獲取更多指導(dǎo)。備注：Cross-Polarization水平極化 一般與Co-Polarization垂直極化相對.極化是指在最大輻射方向上輻射電波的極化，其定義為在最大輻射方向上電場矢量端點運動的軌跡，由于天線本身物理結(jié)構(gòu)等原因，天線輻射遠(yuǎn)場的電場矢量除了有所需要方向的運動外，還在其正交方向上存在分量，這就指的天線的交叉極化。B) PURPOSE This document addresses two issues as

9、sociated with conducted testing of emissions from transmitters with multiple outputs in the same band: 1) Summing emissions. 發(fā)射求和The FCCs emission limits apply to the total of emissions from all outputs of the transmitter or of composite system transmitters. Thus, emission measurements from the tran

10、smitter outputs must be summed before comparing measured emissions to the emission limit. FCC的發(fā)射限值適用于發(fā)射器或復(fù)合系統(tǒng)發(fā)射器的所有輸出的發(fā)射總量。 因此，在將測量的發(fā)射與發(fā)射限制進行比較之前，必須對來自發(fā)射機輸出的發(fā)射測量求和。 Accounting for array gain. 陣列增益計算Correlation between signals transmitted from different antennas can lead to array gain, which increase

11、s the directional gain of the device and leads to higher radiated levels in some directions. The contribution of array gain to the directional gain of the transmitter must be considered in rule parts where conducted in-band emission limits vary with directional gain, or in situations in which conduc

12、ted measurements are combined with directional antenna gain to determine compliance with in-band radiated limits. 根據(jù)不同天線發(fā)射的信號之間的相關(guān)性可以引出陣列增益，這增加了設(shè)備的定向增益并且導(dǎo)致在一些方向上的較高輻射水平。 在傳導(dǎo)帶內(nèi)發(fā)射限制隨著方向增益變化的規(guī)則部分中或者在傳導(dǎo)測量與定向天線增益組合以確定符合帶內(nèi)發(fā)射限制的情況下，必須考慮陣列增益對發(fā)射機的定向增益的貢獻 輻射極限。 These issues are unique to conducted emissions m

13、easurements. In most cases, radiated measurements automatically combine the power emitted from multiple outputs and include the effects of directional gain if the measurements are performed in the direction of maximum response of the transmitter.傳導(dǎo)發(fā)射測量：需要計算定向增益輻射測量：不需要計算，因為輻射測試會自動組合從多個輸出發(fā)射的功率，并且包括方向

14、增益的影響 C) LIMITATIONS This document provides guidance only with respect to summing of emission measurements from multiple outputs and performing directional gain computations. It makes no change in other aspects of measurements and compliance, such as the type of power or power spectral density measu

15、rement to be made (e.g., peak or average) or the methods for making those measurements (e.g., spectrum analyzer setup parameters). 這個文檔只對多天線設(shè)備發(fā)射測量和定向增益計算，不涉及其他測試方法和設(shè)置方面D) DEFINITION Measure-and-sum technique. The conducted emission level (e.g., transmit power or power in specified bandwidth) is meas

16、ured at each antenna port. The measured results at the various antenna ports are then summed mathematically to determine the total emission level from the device. Summing is performed in units that are directly proportional to power (e.g., mW or microvolts-squarednot dBm or microvolts). 測量與求和技術(shù)。在每個天

17、線端口處測量傳導(dǎo)發(fā)射功率（例如，指定帶寬中的發(fā)射功率或功率）。 然后在各個天線端口處的測量結(jié)果在數(shù)學(xué)上求和以確定來自設(shè)備的總發(fā)射功率。 以與功率成正比的單位（例如，mW或微伏平方 - 不是dBm或微伏）執(zhí)行求和。E) GUIDANCE FOR SUMMING EMISSION MEASUREMENTS FROM MULTIPLE OUTPUTS OF A TRANSMITTER OR FROM MULTIPLE TRANSMITTERS 發(fā)射器或多個發(fā)射器的多個輸出的發(fā)射測量的指導(dǎo)Acceptable methodologies for summing emission measurement

18、s from multiple transmitter outputs depend on the type of emission measurement being performed. Three types of emission measurements are considered: in-band power measurements; in-band power spectral density measurements; and out-of-band and spurious emissions measurements. 考慮三種類型的發(fā)射測量：帶內(nèi)功率測量; 帶內(nèi)功率譜

19、密度測量; 帶外和雜散發(fā)射測量。1) In-Band Power Measurements The measure-and-sum technique shall be used for measuring in-band transmit power of a device. Total power is the sum of the conducted power levels measured at the various output ports 總功率是在各個輸出端口處測量的傳導(dǎo)功率的總和2) In-Band Power Spectral Density (PSD) Measurem

20、ents When performing measurements for compliance with PSD limits within the band of operation of a transmitter, any of the three techniques below may be used to combine the emission measurements from multiple outputs prior to comparing to the emission limit. The first is the most accurate method. Th

21、e second and third techniques are offered as simpler alternatives, but they may lead to overestimates of the total PSD when emission levels differ between outputs; consequently, if measurements performed using methods b) or c) exceed the emission limit, the test lab may wish to retest using method a

22、) before declaring that the device fails the emission test. With any of the methods, existing rules and guidance shall be applied in performing the measurements on the individual outputs and in determining the maximum permitted PSD for the device. 當(dāng)在發(fā)射器的操作頻帶內(nèi)執(zhí)行符合PSD限制的測量時，下面的三種技術(shù)中的任一種可以用于在與發(fā)射限度比較之前組

23、合來自多個輸出的發(fā)射測量。 第一種是最準(zhǔn)確的方法。第二和第三技術(shù)被提供為更簡單的替代但是當(dāng)輸出之間的發(fā)射水平不同時，它們可能導(dǎo)致總PSD的過高估計; 因此，如果使用方法b）或c）進行的測量超過發(fā)射限值，則測試實驗室可能希望在聲明設(shè)備未通過發(fā)射測試之前使用方法a）重新測試。 使用任何方法，在執(zhí)行各個輸出的測量和確定設(shè)備的最大允許PSD時，應(yīng)應(yīng)用現(xiàn)有規(guī)則和指導(dǎo)。a) Measure and sum the spectra across the outputs. With this technique, spectra are measured at each output of the devic

24、e at the required resolution bandwidth. The individual spectra are then summed mathematically in linear power units. Unlike in-band power measurements, in which the sum involves a single measured value (output power) from each output, measurements for compliance with PSD limits involve summing entir

25、e spectra across corresponding frequency bins on the various outputs i.e., for a device with NANT transmitter outputs, if the spectrum measurements of the individual outputs are all performed with the same span and number of points, the spectrum value (in watts or milliwatts) in the first spectral b

26、in of output 1 is summed with that in the first spectral bin of output 2 and that from the first spectral bin of output 3, and so on up to the NANTth output to obtain the value for the first frequency bin of the summed spectrum. The summed spectrum value for each of the other frequency bins is compu

27、ted in the same way). 舉個例子：對于具有N個發(fā)射機輸出的設(shè)備，如果各個輸出的頻譜測量都使用相同的Span和掃描點數(shù)：測量出第1端口的第一段頻譜圖（以瓦特或毫瓦為單位）測量出第2端口的第一段頻譜圖測量出第3端口的第一段頻譜圖直到測量出第N端口的第一段頻譜圖, 以相同的方式計算每個端口第一段頻譜圖相加b) Measure and sum spectral maxima across the outputs. With this technique, spectra are measured at each output of the device at the require

28、d resolution bandwidth. The maximum value (peak) of each spectrum is determined. These maximum values are then summed mathematically in linear power units across the outputs. These operations shall be performed separately over frequency spans that have different out-of-band or spurious emission limi

29、ts計算最大值：在標(biāo)準(zhǔn)要求的RBW內(nèi)，線性計算所有的輸出端口的最大值的總和c) Measure and add 10 log(NANT) dB, where NANT is the number of outputs. With this technique, spectrum measurements are performed at each output of the device, but rather than summing the spectra or the spectral peaks across the outputs, the quantity 10 log(NANT)

30、 dB is added to each spectrum value before comparing to the emission limit. The addition of 10 log(NANT) dB serves to apportion the emission limit among the NANT outputs so that each output is permitted to contribute no more than 1/NANTth of the PSD limit specified in the rules. (Note that the 10 lo

31、g(NANT) term in this calculation is not related to that used in array gain calculations, to be discussed later in this document.) 在與發(fā)射限值比較之前，將10 log（N）dB的量加到每個端口的測試值上。將10log（N）dB分配到N跟發(fā)射輸出天線上，每個輸出允許的值不超過標(biāo)準(zhǔn)規(guī)定的PSD限值的1 / N。 （請注意，此計算中的10 log（N）項與陣列增益計算中使用的術(shù)語無關(guān)，本文檔后面將對此進行討論。）3) Out-of-Band and Spurious Em

32、ission Measurements a) Absolute Emission Limits （絕對限值）When performing measurements outside of the band of operation of a transmitter (i.e., out-of-band and spurious emissions), any of the three techniques below may be used to combine the emission measurements from multiple outputs prior to comparing

33、 to the emission limit. The first is the most accurate method. The second and third techniques are offered as simpler alternatives, but they may lead to overestimates of the total emission level when emission levels differ between outputs; consequently, if measurements performed using methods (ii) o

34、r (iii) exceed the emission limit, the test lab may wish to retest using method (i) before declaring that the device fails the emission test. With any of the methods, existing rules and guidance shall be applied in performing the measurements on the individual outputs and in determining the maximum

35、permitted emission level for the device. 當(dāng)在發(fā)射機的操作頻帶外（即，帶外和雜散發(fā)射）執(zhí)行測量時以下三種技術(shù)中的任一種可用于在與發(fā)射限度比較之前組合來自多個輸出的發(fā)射測量。第一種是最準(zhǔn)確的方法。第二和第三技術(shù)被提供為更簡單的替代法(i) Measure and sum the spectra across the outputs as described in sectionE)2)a). Note that the summation must be performed in linear power units, or the equivalent.

36、 For example, if measurement units are microvolts or microvolts/meter, the values shall be squared before summing, and then a square root shall be applied to the sum in order to achieve the equivalent of summing in power units. 如E）2）a）部分所述測量和求和輸出的光譜。注意，求和必須以線性冪單位或等效量來執(zhí)行。例如，如果測量單位是微伏或微伏/米，則在求和之前將該值平方

37、，然后對該和應(yīng)用平方根，以便實現(xiàn)功率單位求和的等效值。為什么要先平方后開方呢,標(biāo)準(zhǔn)差的原理是什么?因為標(biāo)準(zhǔn)差只取正值,先平方后開放就能保證這一點.另外,也能說明方差與標(biāo)準(zhǔn)差的關(guān)系,習(xí)慣上就這樣描述了.標(biāo)準(zhǔn)差 ,也稱均方差是各數(shù)據(jù)偏離平均數(shù)的距離的平均數(shù),它是離均差平方和平均后的方根,用表示.標(biāo)準(zhǔn)差是方差的算術(shù)平方根.標(biāo)準(zhǔn)差能反映一個數(shù)據(jù)集的離散程度.平均數(shù)相同的,標(biāo)準(zhǔn)差未必相同.(ii) Measure and sum spectral maxima across the outputs as described in sectionE)2)b). Note that the summatio

38、n must be performed in linear power units, or the equivalent. For example, if measurement units are microvolts or microvolts/meter, the values shall be squared before 測量和總和輸出兩端的頻譜最大值。(iii) Measure and add 10 log(NANT) dB, where NANT is the number of outputs, as described in section E)2)c). 各加10 log(

39、N) dBb) Relative Limits 相對限值When testing out-of-band and spurious emissions against relative emission limits, tests may be performed on each output individually without summing or adding 10 log(NANT) if the measurements are made relative to the in-band emissions on the individual outputs.For example

40、, if a rule states that out-of-band emissions in a 100 kHz bandwidth must be at least 20dB below the 100 kHz bandwidth in-band that contains the highest power, compliance may be established by confirming that the maximum total out-of-band emission is at least 20 dB below the maximum total in-band PS

41、D, as determined by the “measure and sum the spectra” technique in both instances; alternatively, compliance may be demonstrated by confirming that the maximum out-of-band emission on each individual output is at least 20 dB below the maximum in-band PSD (in 100 kHz bandwidth) on that output. Simila

42、rly, if a rule states that out-of-band emissions in a 1MHz bandwidth must be at least X dB below the transmit power (where X does not vary with transmit power), compliance may be established by confirming that the maximum total out-of-band emission, as determined by the “measure and sum the spectra”

43、 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 bel

44、ow 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. 當(dāng)針對相對發(fā)射限制測試帶外和雜散發(fā)射時，可以單獨對每個輸出執(zhí)行測試

45、，而不求和或增加10個對數(shù)（N）如果測量是相對于單個輸出上的帶內(nèi)發(fā)射進行的。例如，如果規(guī)則規(guī)定在100kHz帶寬中的帶外發(fā)射必須比包含最高功率的帶內(nèi)100kHz帶寬低至少20dB，則可以通過確認(rèn)最大總輸出功率帶外發(fā)射比最大總帶內(nèi)PSD低至少20 dB，如在這兩種情況下通過“測量和求和頻譜”技術(shù)所確定的;或者，可以通過確認(rèn)每個單獨輸出上的最大帶外發(fā)射比該輸出上的最大帶內(nèi)PSD（在100kHz帶寬中）低至少20dB來證明順應(yīng)性。類似地，如果規(guī)則規(guī)定1MHz帶寬中的帶外發(fā)射必須至少比發(fā)射功率低X dB（其中X不隨發(fā)射功率而變化），則可以通過確認(rèn)最大總輸出 - 由“測量和總和頻譜”技術(shù)確定的帶外發(fā)射至

46、少比總發(fā)射功率低X dB;或者，可以通過確認(rèn)每個單獨輸出上的最大帶外發(fā)射比該輸出上的最大發(fā)射功率低至少X dB來證明順應(yīng)性。指定為低于發(fā)射功率X + 10 log（P）dB的發(fā)射限值（其中P是發(fā)射功率）是絕對限值，為本指南的目的不被認(rèn)為是“相對限值”。帶外和雜散發(fā)射必須使用上述a）節(jié)中描述的技術(shù)針對絕對限制進行測試。F) GUIDANCE ON DIRECTIONAL GAIN CALCULATIONS 定向增益計算Some rule parts define a limit on output power or power spectral density that is a functio

47、n 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

48、 gain for devices that transmit on multiple outputs simultaneously in the same band, in the same or in overlapping frequency ranges. 有一些標(biāo)準(zhǔn)會定義：天線系統(tǒng)的定向增益的函數(shù)的輸出功率或功率譜密度的限制。 還可能存在其中進行的測量與定向天線增益組合以確定與輻射限制的符合性的情況。在這種情況下，陣列增益的影響必須包括在針對在相同頻帶中，在相同或重疊的頻率范圍中同時在多個輸出上發(fā)射的設(shè)備的總定向天線增益的計算中。 Array gain results when th

49、e 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 sl

50、ightly 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. 當(dāng)從特定方向觀看時，在不同天線上發(fā)射的信號是正相關(guān)的時，得到陣列增益。在大多數(shù)情況下，當(dāng)從預(yù)期波束方向觀察時，波束成形系統(tǒng)嘗試實現(xiàn)發(fā)射信號之間的100相關(guān)，但實際相關(guān)可能略低。從其多個天線發(fā)射相關(guān)信號的發(fā)射機具有產(chǎn)生陣列增益的潛力，即使這不是意圖。For simplicity

51、, 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 b

52、e 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. 為了簡單起見

53、，這里給出的指導(dǎo)將傳輸分類為相關(guān)的（即，在至少兩個天線上的信號之間存在相關(guān)）或完全不相關(guān)。除非基于以下提供的指導(dǎo)，所發(fā)送的信號被分類為完全不相關(guān)的，否則為了計算定向增益的目的，信號必須被認(rèn)為是相關(guān)的。在相關(guān)信號的情況下，將基于100相關(guān)性來計算陣列增益，即使實際相關(guān)性較低，除了在涉及循環(huán)延遲分集或多個空間流的某些情況下。1) Categorization as Correlated or Completely Uncorrelated分類：相關(guān)或完全不相關(guān)For the purposes of this guidance, transmitter output signals are cons

54、idered correlated if any of the following are true: 以下情況被視為是相關(guān)性的 The same digital data are transmitted from two or more antennas in a given symbol period, even with different coding or phase shifts; Correlation between two transmitted signals exists at any frequency and time delay; or, Multiple tran

55、smitter outputs serve to focus energy in a given direction or to a given receiver; The operating mode combines correlated techniques with uncorrelated techniques. 在給定符號周期中，即使具有不同的編碼或相移，從兩個或更多個天線發(fā)送相同的數(shù)字?jǐn)?shù)據(jù);兩個發(fā)射信號之間的相關(guān)性存在于任何頻率和時間延遲; 或者多個發(fā)射器輸出用于在給定方向或給定接收器聚焦能量;操作模式將相關(guān)技術(shù)與不相關(guān)技術(shù)相結(jié)合。Otherwise, the output si

56、gnals are considered completely uncorrelated. 否則就是無相關(guān)性的產(chǎn)品Correlated signals include, but are not limited to, signals transmitted in any of the following modes: 以下產(chǎn)品均為相關(guān)性的 Any transmit beamforming mode, whether fixed or adaptive (e.g., phased array modes, closed loop MIMO modes, Transmitter Adaptive

57、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

58、, 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 requi