RF exposure Information

FCC ID: RI7HE9223GR

RF Exposure Info

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FCCID_3226531

AT4wireless, S.A.U
Parque Tecnologico de Andalucía,
C/ Severo Ochoa 2
29590 Campanillas
Málaga, España

Subject: RF exposure analysis for the equipment with FCC ID: RI7HE9223GR; IC: 5131A-HE9223GR

The device model: HE922-3GR (FCC ID: RI7HE9223GR; IC: 5131A-HE9223GR) is designed to be installed in and used in mobile exposure
conditions.

The antennas used for this device must be installed to provide a separation distance of at least 20 cm from all the persons and must not be co-
located or operating in conjunction with any other antenna or transmitter.

MPE exposure limits

The table below is excerpted from Table 1B of 47 CFR 1.1310 titled Limits for Maximum Permissible Exposure (MPE), Limits for General
Population/Uncontrolled Exposure:

                         Frequency Range (MHz)                       Power density (mW/cm2)                       Averaging time (minutes)
                                300 – 1500                                  f (MHz) /1500                                      30
                              1500 – 100.000                                       1,0                                         30

The table below is excerpted from RSS-102, Issue 5, section 4, titled “RF Field Strength Limits for Devices Used by the General Public
(Uncontrolled Environment)”:

                         Frequency Range (MHz)                          Power density (W/m2)                     Reference Period (minutes)
                                                                                           0.6834
                                300 – 6000                                 0.02619ƒ                                             6
                               6000 - 15000                                           10                                        6
                              15000 - 150000                                          10                                 616000/ ƒ 1.2


Compliance analysis

                               PG
Using the equation       S            to calculate the exposure to electromagnetic fields
                              4R 2
where:      S = power density (in appropriate units, e.g. mW/cm 2)
            P = power input to the antenna (in appropriate units, e.g., mW)
            G = power gain of the antenna in the direction of interest relative to an isotropic radiator
            R = distance to the center of radiation of the antenna (appropriate units, e.g., cm)

compliance with FCC and IC MPE and EIRP limits is demonstrated based on the following calculations:

      1. Standalone analysis
         1.1    RF exposure in 2.4 GHz band:

Calculations done using the antenna gain specified for this band.


                                                 Maximum
                                     Reference
                                                 conducted                             Evaluation   Antenna              MPE limit    MPE limit
                         Frequency   frequency                                                                   S                                  Worst    MPE Ratio
Frequency                                          output                Duty cicle     distance     gain                 in USA     in Canada
               Mode        Range      (Lowest                TX slots                                         (mW/cm^2                            case MPE    (S/MPE
   Band                                            power                    (%)
                           (MHz)        freq.)                                                                    )                                 limit      limit)
                                                                                           R (cm)    (dBi)               (mW/cm2)    (mW/cm2)
                                        (MHz)
                                                 Pin (dBm)

                           2402 -
  2,4 ISM      BLE                    2402,0       5,49        N/A        100,0%             20      2,30      0,0012     1,0000      0,5351       0,5351     0,0022
                            2480
             BL + EDR      2402 -
  2,4 ISM                             2402,0       6,27        N/A        100,0%             20      2,30      0,0014     1,0000      0,5351       0,5351     0,0027
              (GFSK)        2480
             BL + EDR
                           2402 -
  2,4 ISM      (pi/4-                 2402,0       6,90        N/A        100,0%             20      2,30      0,0017     1,0000      0,5351       0,5351     0,0031
                            2480
              DQPSK)
             BL + EDR      2402 -
  2,4 ISM                             2402,0       6,82        N/A        100,0%             20      2,30      0,0016     1,0000      0,5351       0,5351     0,0030
             (8-DPSK)       2480
              WiFi 2.4
                           2412 -
  2,4 ISM       GHz                   2412,0       19,32       N/A        100,0%             20      2,30      0,0289     1,0000      0,5366       0,5366     0,0539
                            2462
             (802.11b)
              WiFi 2.4
                           2412 -
  2,4 ISM       GHz                   2412,0       17,21       N/A        100,0%             20      2,30      0,0178     1,0000      0,5366       0,5366     0,0332
                            2462
             (802.11g)
              WiFi 2.4
                GHz        2412 -
  2,4 ISM                             2412,0       16,42       N/A        100,0%             20      2,30      0,0148     1,0000      0,5366       0,5366     0,0276
            (802.11n20      2462
                 ))


     1.2    Maximum antenna gains for GSM and UMTS interfaces. Calculations done to comply with
MPE and EIRP limits
Now we calculate the maximum antenna gains so compliance with MPE and EIRP in both USA and Canada is fulfilled.

                                                                                                                                                                      Maximu
                                                                                                                                                                          m
                                                                                                                                                                      Antenna
                                                                                                                                                                        gain
                                         Maximu                                                                                         Maximu    Maximu    Maximu
                                                                                                                    IC EIRP                                               to
                              Referen       m                                                              FCC                Antenna       m         m         m
                                                                                                                      limit                                           comply
                                  ce     conduct                        Evaluati     MPE        MPE       EIRP                  gain    Antenna   Antenna   Antenna
                   Frequen                                                                                             per                                              MPE
                              frequen       ed                  Duty      on       limit in   limit in     limit              to meet     gain      gain      gain
                      cy                                                                                             SRSP-                                              limit
Frequen                           cy      output                cicle   distanc      USA      Canada        per                 FCC     to meet   to meet   to meet
           Mode     Range                           TX slots                                                          503,                                               and
cy Band                       (Lowest     power                            e                             §22,913,               MPE       FCC      ISED      ISED
                                                                                                                     SRSP-                                             EIRP
                                freq.)     (per                 (%)                (mW/cm     (mW/cm     §24,232                limit    EIRP       MPE      EIRP
                    (MHz)                                                                                              510                                              in all
                                         tune-up)                        (cm)        ^2)        ^2)                                       limit     limit     limit
                                                                                                                                                                       bands
                               (MHz)                                                                       (W)                G (dBi)
                                                                                                                     (W)                                              in USA
                                          (dBm)                                                                                         G (dBi)   G (dBi)   G (dBi)
                                                                                                                                                                         and
                                                                                                                                                                      Canada

                                                                                                                                                                       (dBi)


          GSM/G
  PCS      PRS     1850,2 -
                              1850,2      30,90        4       50,0%      20        1,00       0,45        2,00      2,00      9,12      2,11      5,63      2,11
  1900    (class    1909,8
            10)




 UMTS              1852,4 -
          WCDMA               1852,4      23,40       N/A      100,0%     20        1,00       0,45        2,00      2,00      13,61     9,61      10,12     9,61       2,11
  B2                1907,6




 UMTS              1852,4 -
          HSUPA               1852,4      23,40       N/A      100,0%     20        1,00       0,45        2,00      2,00      13,61     9,61      10,12     9,61
  B2                1907,6




          GSM/G
  GSM      PRS     824,2 -
                               824,2      32,50        4       50,0%      20        0,55       0,26       11,48      11,50     4,92      8,09      1,63      8,10
  850     (class    848,8
            10)




 UMTS              826,4 -
          WCDMA                826,4      23,50       N/A      100,0%     20        0,55       0,26       11,48      11,50     10,92     17,09     7,63      17,10      1,63
  B5                846,6




 UMTS              826,4 -
          HSUPA                826,4      23,50       N/A      100,0%     20        0,55       0,26       11,48      11,50     10,92     17,09     7,63      17,10
  B5                846,6




2.        Co-location analysis
2.1       Co-location with other transmitter in mobile exposure conditions
As specified in the operational description, cellular transmitter can work simultaneously with the transmitter in the 2.4GHz band so an analysis of the
co-location with other transmitter in mobile exposure conditions is required.

Only one of these 2.4 GHz modes works at a given moment and it can work simultaneously with any of the cellular modes.

According to KDB 447498 D01 General RF Exposure Guidance v06, 7.2:

          Simultaneous transmission MPE test exclusion applies when the sum of the MPE ratios for all simultaneous transmitting antennas
          incorporated in a host device, based on calculated or measured field strengths or power density, is ≤ 1.0.

As the maximum calculated MPE ratio for the device is 0.0539 in the mode WiFi 2.4 GHz (802.11n20), the product can be co-located with other
antennas in the cellular mode providing that the sum of the MPE ratios for all the other simultaneous transmitting antennas incorporated in a host
device, based on calculated or measured field strengths or power density is ≤ 1.0 – 0.0539 = 0.9461


2.2         RF exposure for GSM and UMTS modes

The antenna gains calculated in 1.2 are in compliance with 2 criteria, MPE and EIRP limits for both countries, USA and Canada.

Nevertheless there is a third criterion that we need to meet. As the cellular interface can work simultaneously with the 2.4 GHz interface, the MPE
ratio for each cellular mode must also be in compliance with the MPE Ratio for use in co-location defined in 2.1

The antenna gain of 2.11 dBi for the 1900 MHz band is not a problem.

If we would use an antenna gain of 1.63 dBi in the 850 MHz band, the MPE Ratio for the GSM/GPRS (class 10) mode would be greater than
0.9461

Hence, to comply with this third criterion of MPE ratio to work in co-location below 0.9461, the antenna gain has to be reduced until 1.36 dBi

The table below shows the values of S and the MPE ratio under these conditions

                                                                                                                Maximum
                                                                                                                 Antenna
                                                            Maximum                                                gain
                                             Reference      conducted                                           to comply
                             Frequency       frequency        output                 Duty        Evaluation     MPE limit               MPE limit in    MPE limit in    Worst    MPE Ratio
                                                                                                                               S
Frequency                      Range          (Lowest         power         TX       cicle        distance      and EIRP                  USA            Canada         case
               Mode
  Band                                          freq.)      (per tune-     slots                                   in all                                               MPE       (S/MPE
                                                                                                                            (mW/cm^2)
                                (MHz)                          up)                    (%)          (cm)          bands in               (mW/cm^2)        (mW/cm^2)      limit      limit)
                                               (MHz)                                                             USA and
                                                            Pin (dBm)                                            Canada

                                                                                                                  (dBi)
             GSM/GPRS          1850,2 -
PCS 1900                                       1850,2          30,90           4    50,0%           20            2,11       0,1989       1,0000           0,4477       0,4477    0,4444
              (class 10)        1909,8
                               1852,4 -
 UMTS B2      WCDMA                            1852,4          23,40          N/A   100,0%          20            2,11       0,0708       1,0000           0,4480       0,4480    0,1579
                                1907,6
                               1852,4 -
 UMTS B2      HSUPA                            1852,4          23,40          N/A   100,0%          20            2,11       0,0708       1,0000           0,4480       0,4480    0,1579
                                1907,6
             GSM/GPRS          824,2 -
 GSM 850                                       824,2           32,50           4    50,0%           20            1,36       0,2423       0,5495           0,2576       0,2576    0,9407
              (class 10)         848,8
                               826,4 -
 UMTS B5      WCDMA                            826,4           23,50          N/A   100,0%          20            1,36       0,0610       0,5509           0,2581       0,2581    0,2364
                                 846,6
                               826,4 -
 UMTS B5      HSUPA                            826,4           23,50          N/A   100,0%          20            1,36       0,0610       0,5509           0,2581       0,2581    0,2364
                                 846,6



3           Conclusion

To meet all the established criteria, the antenna gains in the cellular modes must be:

            Frequency range                                       Antenna gain
            850 MHz band                                          1.36 dBi
            1900 MHz band                                         2.11 dBi


Final MPE with Co-location.
The worst cases of working in co-location are below.
They are WiFi 2.4 GHz (802.11b) and GSM/GPRS (class 10)

The antenna gain used for the 850 MHz band is the optimum case to comply with the MPE and EIRP limits and additionally give an MPE ratio
below 0.9461 as calculated in 2.2

                                                        Maximum
                                                        conducted
                                          Reference
                                                          output                                   Evaluation     Antenna               MPE limit       MPE limit
                           Frequency      frequency                                                                            S                                      Worst      MPE Ratio
Frequency                                                 power                     Duty cicle      distance       gain                  in USA        in Canada
              Mode           Range         (Lowest                     TX slots                                             (mW/cm^2                                case MPE      (S/MPE
   Band                                                 (per tune-                     (%)
                             (MHz)           freq.)                                                                             )                                     limit        limit)
                                                           up)                                      R (cm)         (dBi)                (mW/cm2)       (mW/cm2)
                                             (MHz)
                                                        Pin (dBm)
             WiFi 2.4
                            2412 -
 2,4 ISM       GHz                         2412,0         19,32          N/A         100,0%           20            2,30      0,0289     1,0000         0,5366         0,5366     0,0539
                             2462
            (802.11b)
            GSM/GPR
                            824,2 -
GSM 850      S (class                       824,2         32,50           4          50,0%            20            1.36      0,2423     0,5495         0,2576         0,2576     0,9407
                             848,8
                10)


The sum of MPE ratios in this case is 0.0539 + 0.9407 = 0.9946 ≤ 1.0

The sum of S for both modes is 0.0289 + 0.2423 = 0.2712 (mW/cm^2)  S = 2.712 W/m^2

In compliance with all limits of MPE, EIRP and MPE for working in co-location

PA




By: Brian Tucker
Title: Senior Vice President of Quality
Company: Telit Wireless Solutions, Inc.



Document Created: 2016-12-12 17:20:56
Document Modified: 2016-12-12 17:20:56

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