16
Fanny Mlinarsky - May 06, 2014 As cellular and Wifi systems move from single to multiple wireless signals, handsets and the chipsets that go inside them need testing. Because of the multiple signals in a MIMO (multiple input, multiple output) system, testing handsets using a wired connection doesn’t emulate the needed test conditions. This 3-part series will take a deep dive into the modern radio architecture and MIMO signaling. It will examine sophisticated new baseband algorithms designed to optimize throughput of 802.11n/ac and 4G systems. We will study the nature of a MIMO airlink channel and RF propagation and outline the factors that impact MIMO throughput. Finally, we will look at methods of measuring throughput and characterizing the behavior of baseband algorithms. How MIMO radios work Getting repeatable and consistent performance measurements of 802.11n/ac and LTE MIMO devices is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to the changing channel conditions. Wireless environment constantly changes vs. time, frequency and motion of radios and reflectors. The time-variability of path loss, multipath, Doppler and interference often baffles the decision- making logic of the adaptation algorithms and sometimes puts radios into unintended states. IEEE 802.11ac radios can change their data rate over three orders of magnitude, ranging from 1 Mbit/s to over 1 Gbit/s for products sold today, with a theoretical maximum rate of 6.9 Gbits/s. Data rate adaptation happens on a packet-by-packet basis in response to time-variable airlink impairments, such as signal fades or interference. The sophisticated adaptation capability resides in the Baseband layer of the radio—the intelligent logic layer. Radios have evolved since mobile phones first emerged in the 1970s from purely analog to very sophisticated logic and this logic we will examine here. Early radios directed the voice signal out of the microphone to modulate the RF carrier (Figure 1 left). Modern radios include a baseband layer that houses the (DSP)—a technology that changes everything about radios and enables dynamic adaptation to the time-variable channel conditions, resulting in vast improvements in throughput and range.

Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

  • Upload
    others

  • View
    2

  • Download
    0

Embed Size (px)

Citation preview

Page 1: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

Fanny Mlinarsky - May 06, 2014

As cellular and Wifi systems move from single to multiple wireless signals, handsets and the chipsetsthat go inside them need testing. Because of the multiple signals in a MIMO (multiple input, multipleoutput) system, testing handsets using a wired connection doesn’t emulate the needed testconditions.

This 3-part series will take a deep dive into the modern radio architecture and MIMO signaling. Itwill examine sophisticated new baseband algorithms designed to optimize throughput of 802.11n/acand 4G systems. We will study the nature of a MIMO airlink channel and RF propagation and outlinethe factors that impact MIMO throughput. Finally, we will look at methods of measuring throughputand characterizing the behavior of baseband algorithms.

How MIMO radios workGetting repeatable and consistent performance measurements of 802.11n/ac and LTE MIMO devicesis, for several reasons, a monumental challenge. For example:

Modern wireless devices are designed to adapt automatically to the changing channel conditions.●

Wireless environment constantly changes vs. time, frequency and motion of radios and reflectors.●

The time-variability of path loss, multipath, Doppler and interference often baffles the decision-●

making logic of the adaptation algorithms and sometimes puts radios into unintended states.

IEEE 802.11ac radios can change their data rate over three orders of magnitude, ranging from 1Mbit/s to over 1 Gbit/s for products sold today, with a theoretical maximum rate of 6.9 Gbits/s. Datarate adaptation happens on a packet-by-packet basis in response to time-variable airlinkimpairments, such as signal fades or interference.

The sophisticated adaptation capability resides in the Baseband layer of the radio—the intelligentlogic layer. Radios have evolved since mobile phones first emerged in the 1970s from purely analogto very sophisticated logic and this logic we will examine here.

Early radios directed the voice signal out of the microphone to modulate the RF carrier (Figure 1left). Modern radios include a baseband layer that houses the (DSP)—a technology that changeseverything about radios and enables dynamic adaptation to the time-variable channel conditions,resulting in vast improvements in throughput and range.

Page 2: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

Figure 1. A traditional analog radio (left) would modulate a signal onto an RF carrier. In abaseband radio (right), baseband logic can make the radio adaptable to time-variable

wireless channel conditions.

Today's MIMO 802.11n/ac and LTE radios have more complex adaptation algorithms than legacySISO (Single Input Single Output) 2G/3G and 802.11a/b/g devices. While SISO devices only varymodulation, MIMO radios work with a more complex MCS (Modulation Coding Scheme).

An MCS includes the following variables: modulation, coding rate, GI (guard interval), channelwidth, and the number of spatial streams. Thus, MIMO adaptation algorithms have several degreesof freedom, as summarized in Table 1. A spreadsheet found here provides the formulas andcomputes data rates for all 802.11n and 802.11ac MCSs as they are defined in the IEEE 802.11standard. By studying the spreadsheet, you will understand how the variables listed in Table 1combine to set the data rate on the airlink.

Table 1. Wireless adaptation techniques typically supported by baseband logic.

The technique of transmitting multiple spatial streams in the same frequency channel is called SM(Spatial Multiplexing). SM only works under favorable channel conditions, that is, in wirelesschannels with low signal to noise ratio (SNR) and low MIMO correlation. MIMO modes oftransmission are explained in Table 2.

Page 3: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

Table 2: MIMO modes of transmission.

Commercial wireless chipsets typically support a subset of the MIMO modes outlined in Table 2 andsome implement other proprietary modes. In the fast-changing wireless environment and with real-time decision making process, adaptation algorithms are still evolving and engineers are strugglingto optimize throughput under all conditions. Any odd behavior or faults with adaptation algorithmscan be difficult to catch in the field amidst constantly changing uncontrolled interference and motionof devices and reflectors.

Let’s look at the time-variable factors that impact MIMO throughput, outlined in Table 3. These areexplained in detail in the octoScope white paper, Throughput Test Methods for MIMO Radios.

Page 4: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

Table 3. Factors that impact MIMO throughput.

When considering a controlled environment wireless testbed, you can use Table 3 as a guide. In part2, we will focus on controlled environment MIMO test beds.

Page 5: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

0HDVXUH�WKURXJKSXW�RI�FHOOXODU�DQG�:L)L0,02�UDGLRV��SDUW��)DQQ\�0OLQDUVN\���0D\���������

,Q�3DUW���RI�WKLV�VHULHV��ZH�SUHVHQWHG�WKH�EDFNJURXQG�RI�KRZ�0,02�UDGLRV�ZRUN��:H�H[DPLQHGZLUHOHVV�DGDSWDWLRQ�WHFKQLTXHV�DQG�0,02�PRGHV�RI�WUDQVPLVVLRQ��:H�DOVR�RXWOLQHG�WKH�IDFWRUV�WKDWLPSDFW�0,02�WKURXJKSXW��1RZ�LQ�3DUW����ZH�FRPSDUH�WKH�FRQGXFWHG�PHDVXUHPHQW�WHFKQLTXHV�WRQHZ�RYHU�WKH�DLU��27$��WHFKQLTXHV��:HOO�H[SORUH�WKH�FKDOOHQJHV�RI�0,02�27$�WHVW�PHWKRGV�DQGIDFWRUV�WKDW�FDQ�PDNH�PHDVXUHPHQWV�QRQ�UHSHDWDEOH�

&RQWUROOHG�FKDQQHO��UHSHDWDEOH�WHVWV$V�RXWOLQHG�LQ�3DUW����HQJLQHHUV�WHVWLQJ�0,02�UDGLRV�QHHG�WR�FUHDWH�D�UDQJH�RI�FKDQQHO�FRQGLWLRQVIURP�ZKLFK�WR�YDOLGDWH�D�UDGLRV�DGDSWDELOLW\�DQG�WKURXJKSXW�SHUIRUPDQFH��7KLV�FDQ�EH�DFFRPSOLVKHGXVLQJ�D�0,02�IDGHU�VXFK�DV�$]LPXWK�$&(��6SLUHQW�95���RU�$QLWH�3URSVLP���RU�D�PXOWLSDWK�HPXODWRU�VXFK�DV�WKH�RFWR6FRSH�03(��$�IDGHU�RU�D�PXOWLSDWK�HPXODWRU�FDQ�FRQQHFW�WZR�RU�PRUH�GHYLFHVWKURXJK�FDEOHV�WR�WKH�GHYLFH�DQWHQQD�SRUWV�RU�RYHU�WKH�DLU��)RU�GHYLFHV�VXFK�DV�VPDUWSKRQHV��WDEOHWV�RU�VHQVRUV�ZLWK�GLIILFXOW�WR�UHDFK�LQWHUQDO�DQWHQQDV��27$�FRXSOLQJ�LV�KLJKO\�GHVLUDEOH�

:KHQ�PRVW�ZLUHOHVV�FRPPXQLFDWLRQ�UDGLRV�ZHUH�6,62��VLQJOH�LQSXW�VLQJOH�RXWSXW��DQG�DQWHQQDVZHUH�H[WHUQDO��\RX�FRXOG�WHVW�D�KDQGVHW�RU�RWKHU�GHYLFH�E\�GLVFRQQHFWLQJ�LWV�DQWHQQD�DQG�FRQQHFWLQJD�SURJUDPPDEOH�DWWHQXDWRU�RU�D�IDGHU�EHWZHHQ�D�0DVWHU��UHIHUHQFH��GHYLFH�DQG�D�'87��)LJXUH���OHIW���7HVWLQJ�RI�0,02�UDGLRV�ZLWK�LQWHUQDO�DQWHQQDV�UHTXLUHV�D�0,02�27$�WHVWEHG��)LJXUH���ULJKW�WKDW�VXSSRUW�VWDEOH�DQG�UHSHDWDEOH�0,02�PHDVXUHPHQWV��2I�FRXUVH��FKDOOHQJHV�DULVH�ZKHQ�ZHFRXSOH�VLJQDOV�RYHU�WKH�DLU�LQ�D�VKLHOGHG�ER[�

)LJXUH����5DGLR�WHVW�EHG�DUFKLWHFWXUH�LV�HYROYLQJ�IURP�FRQGXFWHG�6,62�WR�0,02�27$�

Page 6: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

27$�VLJQDO�FRXSOLQJ7KHUH�DUH�WZR�LVVXHV�ZLWK�27$�PHDVXUHPHQWV�LQVLGH�D�PHWDO�HQFORVXUH��)LUVW��WKH�VLJQDO�FDQ�UHIOHFWIURP�WKH�PHWDO�ZDOOV�DQG�IRUP�QXOOV�FRPSOHWHO\�DOWHULQJ�WKH�VKDSH�RI�WKH�ILHOG�DQG�LQWURGXFLQJSRVLWLRQDO�YDULDWLRQ�RI�VLJQDO�SRZHU��$QHFKRLF�FKDPEHUV�PXVW�EH�XVHG�WR�DYRLG�WKLV�YDULDWLRQ��5HIHUWR�RFWR6FRSH�ZKLWH�SDSHU��7KURXJKSXW�7HVW�0HWKRGV�IRU�0,02�5DGLRV��IRU�PRUH�GHWDLOV�

6HFRQG��ZKHQ�WHVWLQJ�GHYLFHV�ZLWK�LQWHUQDO�DQWHQQDV��GHYLFH�RULHQWDWLRQ�ZLWK�UHVSHFW�WR�WKH�WHVWDQWHQQDV�FDQ�KDYH�D�VLJQLILFDQW�LPSDFW�RQ�WKH�PHDVXUHG�WKURXJKSXW��7KH�UHDVRQ�LV�WKDW�WKH�UDGLDWHGILHOG�LV�RIWHQ�QRQ�XQLIRUP�ZLWK�VWURQJ�OREHV�DQG�QXOOV��DV�VKRZQ�LQ�)LJXUH���RQ�WKH�ULJKW��7KH�ILHOG�RIDQ�LQWHUQDO�DQWHQQD�W\SLFDOO\�KDV�QXOOV�DQG�SHDNV�EHFDXVH�WKH�VLJQDO�FDQ�EH�EORFNHG�E\�EDWWHULHV�3&%�JURXQG�SODQHV��DQG�RWKHU�PHWDO�VXUIDFHV�

)LJXUH����/HIW��$Q�RFWR%R[�VPDOO�DQHFKRLF�FKDPEHU�ZLWK�D�EXLOW�LQ�WXUQWDEOH�FDQ�URWDWH�WKH'87�ZKLOH�PHDVXULQJ�0,02�WKURXJKSXW�SHUIRUPDQFH��5LJKW��$Q�H[DPSOH�0,02�DQWHQQDILHOG�SDWWHUQ�VKRZV�UHG�DUHDV�LQGLFDWLQJ�KLJK�DQWHQQD�JDLQ�DQG�EOXH�DUHDV�LQGLFDWLQJ�QXOOVLQ�WKH�DQWHQQD�ILHOG�

:KHQ�SHUIRUPLQJ�27$�WHVWV��\RX�VKRXOG�URWDWH�WKH�GHYLFH�ZLWK�UHVSHFW�WR�WKH�WHVW�DQWHQQDV��7KDW�OHWV\RX�DYHUDJH�WKH�SHUIRUPDQFH�YHUVXV�RULHQWDWLRQ�RU�\RX�FDQ�ILQG�WKH�RSWLPXP�DQG�ZRUVW�FDVH�'87RULHQWDWLRQ�

%HDPIRUPLQJ�WHVW�XVLQJ�D�WXUQWDEOH7KH�ODWHVW�������DF�$3V��DFFHVV�SRLQWV��IHDWXUH�EHDPIRUPLQJ�FDSDELOLWLHV�b�WKH�DELOLW\�RI�WKH�$3�WRDGDSW�WKH�SRZHU�DQG�SKDVH�RQ�HDFK�RI�LWV�0,02�DQWHQQDV�WR�GLUHFW�VLJQDO�HQHUJ\�VR�DV�WR�RSWLPL]HWKH�UDQJH�RI�WKH�OLQN��%HDPIRUPLQJ�W\SLFDOO\�UHTXLUHV�WKDW�D�FKDQQHO�VRXQGLQJ�EH�SHUIRUPHG�EHWZHHQWKH�$3�DQG�WKH�WDUJHW�FOLHQW�

2QH�SRVVLEOH�ZD\�WR�WHVW�EHDPIRUPLQJ�FDSDELOLW\�RI�WKH�QHZ�������DF�GHYLFHV�LV�WR�XVH�D�WXUQWDEOH�WRURWDWH�WKH�'87�ZLWK�UHVSHFW�WR�WHVW�DQWHQQDV��ILUVW�ZLWK�EHDPIRUPLQJ�RQ�DQG�WKHQ�ZLWK�EHDPIRUPLQJRII��7KH�GLIIHUHQFH�LQ�SHUIRUPDQFH�YHUVXV�'87�RULHQWDWLRQ��VLJQDO�SRZHU��DQG�PXOWLSDWK�FRQGLWLRQVZLOO�LQGLFDWH�KRZ�PXFK�LPSDFW�EHDPIRUPLQJ�KDV�RQ�WKURXJKSXW�

,WV�LPSRUWDQW�WR�SHUIRUP�WKLV�WHVW�LQ�WKH�SUHVHQFH�RI�PXOWLSDWK�DQG�SDWK�ORVV�EHFDXVH�WKH�LPSDFW�RIEHDPIRUPLQJ�PD\�QRW�EH�DSSDUHQW�LQ�LGHDO�FRQGLWLRQV��(PXODWLRQ�RI�PXOWLSDWK�DQG�SDWK�ORVV�LQ�WKHWHVWEHG�ZLOO�EH�GLVFXVVHG�LQ�3DUW���

0XOWLSDWK

0XOWLSDWK

Page 7: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

7R�KHOS�HQJLQHHUV�RSWLPL]H�UDGLR�GHVLJQ�IRU�VSHFLILF�HQYLURQPHQWV��H�J��SKRQHV�IRU�RXWGRRUV��$3V�IRULQGRRUV���WKH�ZLUHOHVV�LQGXVWU\�KDV�GHYHORSHG�D�IHZ�VWDQGDUG�FKDQQHO�PRGHOV�IRU�LQGRRU�DQG�RXWGRRUVSDFHV��&RPPHUFLDO�IDGHUV�LPSOHPHQW�WKHVH�FKDQQHO�PRGHOV�WR�HQDEOH�UDGLR�WHVWLQJ�LQ�D�UDQJH�RIVWDQGDUGV�EDVHG�HPXODWHG�HQYLURQPHQWV�

,(((�������Q�DF�FKDQQHO�PRGHOV�FKDUDFWHUL]H�LQGRRU�HQYLURQPHQW��$�VXPPDU\�RI�,(((�������Q�DFFKDQQHO�PRGHOV�LV�VKRZQ�LQ�7DEOH����1RWLFH�KRZ�GHOD\�DQG�GHOD\�VSUHDG�LQ�7DEOH���LQFUHDVHV�DVODUJHU�VSDFHV�DUH�EHLQJ�PRGHOHG�E\�WKH�,(((�PRGHOV�$�WKURXJK�)�

7DEOH����,(((�������Q�DF�VWDQGDUG�FKDQQHO�PRGHOV�� 0RGHO�$�LV�D�IODW�IDGLQJ�PRGHO��QRGHOD\�VSUHDG�DQG�QR�PXOWLSDWK�

'HOD\�VSUHDG�LV�WKH�GLIIHUHQFH�EHWZHHQ�WKH�ORQJHVW�DQG�VKRUWHVW�GHOD\V�RI�WKH�UHIOHFWLRQV�DQG�LVVWDWLVWLFDO�LQ�QDWXUH��5DGLRV�DUH�GHVLJQHG�WR�RSHUDWH�ZLWK�D�FHUWDLQ�UDQJH�RI�PXOWLSDWK�GHOD\�VSUHDG�ZKLFK�FDQ�EH�ORQJHU�RXWGRRUV�DQG�VKRUWHU�LQGRRUV��,(((�������Q�DF�FKDQQHO�PRGHOV�DUH�GHILQHG�LQWHUPV�RI��FOXVWHUV��RI�PXOWLSDWK�UHIOHFWLRQV��$�FOXVWHU�LV�D�JURXS�RI�UD\V�UHIOHFWLQJ�WRJHWKHU�IURP��IRUH[DPSOH��D�FRUQHU�RI�D�URRP�RU�D�ZDOO�DQG�SURSDJDWLQJ�DV�D�JURXS��7KH�,(((�0RGHO�%��PRGHOLQJ�DKRXVH��KDV�WZR�FOXVWHUV��0RGHO�'��PRGHOLQJ�D�ODUJHU�VSDFH��KDV�WKUHH�FOXVWHUV�

$�FOXVWHU�W\SLFDOO\�DUULYHV�DW�WKH�UHFHLYHU�PXOWLSOH�WLPHV�DV�LW�ERXQFHV�EDFN�DQG�IRUWK�EHWZHHQRSSRVLWH�VXUIDFHV��(DFK�WLPH�WKH�FOXVWHU�DUULYHV�DW�WKH�UHFHLYHU��LWV�SRZHU�LV�ORZHU��)RU�LQGRRUPRGHOV��VXFK�DV�WKH�,(((�PRGHOV��PXOWLSOH�FOXVWHUV�FDQ�RYHUODS�LQ�WLPH��IRUPLQJ�D�SDUWLFXODU�3'3�3RZHU�'HOD\�3URILOH��RI�WKH�VLJQDO�DW�WKH�UHFHLYHU��)LJXUH���VKRZV�WKH���FOXVWHU�3'3�RI�0RGHO�'�

Page 8: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

)LJXUH����,Q�DQ�,(((�0RGHO�'���FOXVWHU�3'3��HDFK�FOXVWHU�ERXQFHV�EDFN�DQG�IRUWK�PRQRWRQLFDOO\�GLPLQLVKLQJ�LQ�SRZHU�ZLWK�HDFK�ERXQFH��0XOWLSOH�FOXVWHUV�RYHUODS�LQ�WLPH

DQG�DGG�WRJHWKHU�WR�IRUP�3'3�

3'3�LV�D�SORW�RI�FOXVWHUHG�HQHUJ\�UHIOHFWLRQV�YV��WLPH��)LJXUH����DQG�LV�D�IXQFWLRQ�RI�GHOD\�VSUHDG�LQWKH�FKDQQHO��3'3�IRU�VWDQGDUGV�EDVHG�FKDQQHO�PRGHOV�LV�GHILQHG�E\�VWDQGDUGV�ERGLHV��VXFK�DV�,(((DQG��*33�

3'3�LV�DNLQ�WR�D�VLJQDWXUH�RI�D�ZLUHOHVV�FKDQQHO�DQG�LV�XQLTXH�IRU�HDFK�HQYLURQPHQW��%HFDXVH�HYHU\HQYLURQPHQW�LV�XQLTXH��ZH�XVH�WKH�UHSUHVHQWDWLYH�LQGXVWU\�VWDQGDUG�PRGHOV�LQ�7DEOH���IRU�WHVWLQJUDGLRV��6WDQGDUGV�EDVHG�FKDQQHO�PRGHOV�VSHFLI\�VWDWLVWLFDOO\�W\SLFDO�3'3V�IRU�D�IHZ�UHSUHVHQWDWLYHHQYLURQPHQWV��$�ZLUHOHVV�WHVWEHG�VKRXOG�EH�DEOH�WR�DFFXUDWHO\�PRGHO�LQGXVWU\�VWDQGDUG�FKDQQHOFRQGLWLRQV��LQFOXGLQJ�PXOWLSDWK�DQG�LQWHUIHUHQFH�

3DUW���IRFXVHV�RQ�HPXODWLQJ�UHDO�OLIH�FKDQQHO�FRQGLWLRQV�DQG�RQ�0,02�27$�WHVWLQJ�LQ�D�VPDOODQHFKRLF�FKDPEHU�

Dave Barnes
Highlight
Page 9: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

0HDVXULQJ�WKURXJKSXW�RI�FHOOXODU�DQG�:L)L0,02�UDGLRV��3DUW��)DQQ\�0OLQDUVN\���-XQH���������

,Q�3DUW���RI�WKLV�VHULHV��ZH�FRPSDUHG�FRQGXFWHG�WKURXJKSXW�PHDVXUHPHQW�WHFKQLTXHV�WR�QHZ�27$�RYHU�WKH�DLU��WHFKQLTXHV��:H�H[DPLQHG�WKH�FKDOOHQJHV�RI�0,02�27$�WHVW�PHWKRGV��LQFOXGLQJ�WLPH�YDULDEOH�ZLUHOHVV�HQYLURQPHQWV�DQG�DQWHQQD�ILHOG�QRQ�XQLIRUPLW\��,Q�WKLV�ILQDO�LQVWDOOPHQW��ZH�GLVFXVVWKH�UHTXLUHPHQWV�DQG�FKDOOHQJHV�RI�FRQVWUXFWLQJ�D�0,02�27$�WHVW�EHG�

0D[LPL]LQJ�0,02�27$�WKURXJKSXW$�0,02�27$�WHVW�EHG�KDV�WR�GHPRQVWUDWH�WKH�XSSHU�OLPLW�RI�WKH�'87�SHUIRUPDQFH�FRQVLVWHQWO\�UHSHDWHGO\��DQG�DW�PXOWLSOH�ORFDWLRQV�DURXQG�WKH�ZRUOG��5HIHUULQJ�EDFN�WR�3DUW���7DEOH����WR�PD[LPL]H0,02�27$�WKURXJKSXW��ZH�QHHG�WR�FUHDWH�D�PXOWLSDWK�HQYLURQPHQW��PDNLQJ�VXUH�WKDW�

7KH�VLJQDO�DUULYHV�DW�WKH�0,02�'87�ZLWK�D�ZLGH�DQJXODU�VSUHDG��L�H��IURP�DOO�GLUHFWLRQV�●

0XOWLSDWK�UHIOHFWLRQV�FRQIRUP�WR�LQGXVWU\�VWDQGDUG�3'3V��SRZHU�GHOD\�SURILOHV�●

7KH�WHVW�EHG�JXDUDQWHHV�UHSHDWDEOH�UHVXOWV●

)RU�/26��OLQH�RI�VLJKW��WUDQVPLVVLRQ��DQJXODU�VSUHDG�LV�D�IXQFWLRQ�RI�JHRPHWU\��7KH�FORVHU�WKH�WHVWDQWHQQD�DUUD\��WKH�ZLGHU�WKH�DQJXODU�VSUHDG��DV�GHPRQVWUDWHG�LQ�)LJXUH���

)LJXUH����1DUURZHU�DQJXODU�VSUHDG�GXH�WR�ORQJHU�GLVWDQFH�WR�WKH�WHVW�DQWHQQD�DUUD\��WRSOHIW���ZLGHU�DQJXODU�VSUHDG�UHVXOWLQJ�IURP�SUR[LPLW\�WR�WKH�WHVW�DQWHQQD�DUUD\��WRS�ULJKW��

7KH�QH[W�TXHVWLRQ�LV��KRZ�WR�HPXODWH�UHDOLVWLF�PXOWLSDWK�FKDUDFWHUL]HG�E\�D�VWDQGDUGV�EDVHG�3'3�LQ�DVPDOO�DQHFKRLF�FKDPEHU"�3DUW���H[SODLQHG�KRZ�WKH�GHOD\�VSUHDG�RI�D�JLYHQ�ZLUHOHVV�FKDQQHO�LV�DIXQFWLRQ�RI�WKH�VL]H�RI�WKH�SK\VLFDO�VSDFH��'HOD\�VSUHDG�LV�VKRUWHU�IRU�VPDOO�URRPV�DQG�ORQJHU�IRUODUJHU�URRPV�RU�RXWGRRU�VSDFHV��&KDQQHO�HPXODWRUV�VXFK�DV�$]LPXWK�$&(��$QLWH�3URSVLP�DQG�6SLUHQW95��HPXODWH�GHOD\�VSUHDG��QRLVH��DQG�PRWLRQ�LQ�D�ZLUHOHVV�FKDQQHO�

6PDOO1HW%XLOGHU�FRP�XVHV�DQ�RFWR%R[�03(�WHVWEHG�WR�HYDOXDWH�DQG�EHQFKPDUN�WKH�SHUIRUPDQFH�RI�������GHYLFHV��)LJXUH����

Page 10: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

)LJXUH����$�KDQGVHW��OHIW��XQGHU�WHVW�LQ�D�FKDPEHU�WKDW�XVHV�PXOWLSOH�0,02�WHVW�DQWHQQDV�ULJKW��

6PDOO1HW%XLOGHU�PHDVXUHV�WKURXJKSXW�XVLQJ�,[&KDULRW�VRIWZDUH�IURP�,[LD��ZKLFK�VXSSRUWVPHDVXUHPHQWV�RQ�WKH�7&3�,3�RU�8'3�,3�OD\HU��0HDVXUHPHQWV�FDQ�DOVR�EH�UHSRUWHG�LQ�WHUPV�RI�3(5�SDFNHW�HUURU�UDWH��RU�%(5��ELW�HUURU�UDWH���EXW�FROOHFWLQJ�3(5�RU�%(5�VWDWLVWLFV�UHTXLUHV�VSHFLDOL]HGWHVW�VRIWZDUH�WKDW�PD\�QRW�DOZD\V�EH�DYDLODEOH�ZKHQ�WHVWLQJ�RII�WKH�VKHOI�GHYLFHV��7KXV��UHYLHZHUVDQG�TXDOLW\�DVVXUDQFH��4$��HQJLQHHUV�RIWHQ�XVH�OD\HU���WUDIILF�IRU�PHDVXULQJ�WKURXJKSXW�

8VLQJ�SURJUDPPDEOH�DWWHQXDWRUV��6PDOO1HW%XLOGHU�FUHDWHV�SORWV�RI�WKURXJKSXW�YHUVXV�SDWK�ORVV��DVVKRZQ�LQ�)LJXUH���

Page 11: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

)LJXUH����([DPSOH�RI�D�WKURXJKSXW�YV��DWWHQXDWLRQ�SORWV�SURGXFHG�E\ZZZ�VPDOOQHWEXLOGHU�FRP�

7KH�,3�OD\HU�WKURXJKSXW�LV�VWURQJO\�LQIOXHQFHG�E\�WKH�,[&KDULRW�WHVW�ILOH�VL]H��7KDWV�EHFDXVH�WKHQHWZRUN�VWDFN�LPSOHPHQWDWLRQ�DQG�WKH�ZD\�7&3�RU�8'3�IUDPHV�JHW�TXHXHG�LQWR�EXIIHUV�DQG�WKHQFRQYHUWHG�E\�WKH��������0$&�OD\HU�LQWR��������SDFNHWV�RQ�WKH�ZLUHOHVV�QHWZRUN��$VVXPLQJ�EDFN�W��EDFN�SDFNHW�WUDQVPLVVLRQ�ZLWK�D�PLQLPXP�LQWHU�SDFNHW�JDS��WKH�ORQJHU�WKH��������SDFNHWV��WKHKLJKHU�WKH�WKURXJKSXW��(DFK��������SDFNHW�FRQWDLQV��������0$&�OD\HU�DQG�7&3�RU�8'3�,3�OD\HUKHDGHUV��ZKLFK�DUH�RYHUKHDG��/RQJHU�WKH�SDFNHWV�UHVXOW�LQ�D�ORZHU�SRUWLRQ�RI�D�SDFNHW�EHLQJ�WKHRYHUKHDG�WUDIILF��7KXV��ODUJHU�WHVW�ILOHV�UHVXOW�LQ�ORQJHU�SDFNHWV�RQ�WKH��������DLUOLQN�PHGLXP�6PDOO1HW%XLOGHU�XVHV�����������WR�����������%\WH�ILOH�VL]H��+LJKHU�WKURXJKSXW��DV�PXFK�DV�GRXEOHWKH�GDWD�UDWH�LQ�VRPH�FDVHV��PD\�EH�DFKLHYDEOH�XVLQJ�,[&KDULRW�KLJK�SHUIRUPDQFH�WKURXJKSXW�VFULSW�ZKLFK�WUDQVPLWV������������%\WH�ILOHV�

,QGXVWU\�VWDQGDUG�FKDQQHO�PRGHOV

,QGXVWU\�VWDQGDUG�FKDQQHO�PRGHOV

RFWR%R[�03(�PRGHOV�3'3�RI�HDFK�0,02�SDWK�SHU�WKH�,(((�������Q�DF�FKDQQHO�PRGHOLQJVSHFLILFDWLRQV��DV�VKRZQ�LQ�)LJXUH����3'3�RI�WKH�,(((�0RGHO�%�LV�GHILQHG�DV�EHLQJ�FRPSRVHG�RI�WZRFOXVWHUV��$�FOXVWHU�LV�D�PRGHO�RI�PXOWLSOH�EDFN�DQG�IRUWK�UHIOHFWLRQV�ZLWK�HDFK�UHIOHFWLRQPRQRWRQLFDOO\�GHFUHDVLQJ�LQ�SRZHU��DV�GHVFULEHG�LQ�3DUW���RI�WKLV�DUWLFOH�VHULHV�

Page 12: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

)LJXUH����7KH�PHDVXUHG�UHVSRQVH�RI�RFWR%R[�03(��VKRZQ�LQ�EOXH��FORVHO\�DSSUR[LPDWHV�WKH,(((�PRGHO�%�3'3��VKRZQ�DV�JUHHQ�FLUFOHV�IRU�FOXVWHU���DQG�UHG�GLDPRQGV�IRU�FOXVWHU���

7KH�IUHTXHQF\�UHVSRQVH�RI�WKH�03(�LV�VKRZQ�LQ�)LJXUHV���DQG���DQG�LV�UHSUHVHQWDWLYH�RI�W\SLFDOPXOWLSDWK�LQ�WKH�KRPH�HQYLURQPHQW�

Page 13: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

)LJXUH����RFWR%R[�03(�IUHTXHQF\�UHVSRQVH�LQ�WKH�����*+]��WRS��DQG���*+]��ERWWRP��:L�)LEDQGV�

7KH�EURDGEDQG�IUHTXHQF\�UHVSRQVH�RI�WKH�03(�LV�VKRZQ�LQ�)LJXUH���

Page 14: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

)LJXUH����RFWR%R[�03(�ZLGHEDQG�IUHTXHQF\�UHVSRQVH�IURP�QHDU�'&�WR���*+]�

1RZ�WKDW�ZH�FDQ�VHW�XS�D�PXOWLSDWK�HQYLURQPHQW�LQ�D�VPDOO�DQHFKRLF�FKDPEHU��ZH�PXVW�JXDUDQWHHWKDW�WKH�WHVW�UHVXOWV�DUH�UHSHDWDEOH�IURP�ODE�WR�ODE�DURXQG�WKH�ZRUOG�

+RZ�WR�VHOHFW�DQ�5)�LVRODWLRQ�FKDPEHU7KHUH�DUH�WKUHH�LVVXHV�WR�EH�DZDUH�RI�ZKHQ�VHOHFWLQJ�DQ�LVRODWLRQ�FKDPEHU�

,VRODWLRQ�VSHFLILFDWLRQV�FDQ�EH�PLVOHDGLQJ�EHFDXVH�WKH\�RIWHQ�GRQbW�LQFOXGH�WKH�LPSDFW�RI�GDWD�DQG��SRZHU�FDEOHV�WKDW�PXVW�SHQHWUDWH�WKH�ZDOOV�RI�WKH�FKDPEHU�WR�SRZHU�DQG�FRQWURO�WKH�'87�LQVLGHGXULQJ�WKH�WHVW�0RVW�VKLHOGHG�ER[HV�RQ�WKH�PDUNHW�DUH�QRW�GHVLJQHG�IRU�27$�FRXSOLQJ��,Q�DGGLWLRQ�WR�KLJK��LVRODWLRQ��27$�VXSSRUW�UHTXLUHV�DEVRUSWLRQ�DQG�VSHFLDO�FRQGLWLRQV�WR�HQDEOH�PXOWL�VWUHDP�0,02WKURXJKSXW�5)�JDVNHWLQJ�FDQ�ZHDU�RXW�DIWHU�D�\HDU�RI�QRUPDO�XVH��VHYHUHO\�FRPSURPLVLQJ�FKDPEHU�LVRODWLRQ���*DVNHWLQJ�VKRXOG�EH�SHHO�DQG�VWLFN�DQG�HDV\�WR�UHSODFH��DV�VKRZQ�LQ�)LJXUH����:KHQ�JDVNHWV�ZHDURXW��LQWHUIHUHQFH�FDQ�SHQHWUDWH�WKH�ER[�WKURXJK�LPSHUIHFW�5)�VHDO�LQ�WKH�GRRU�DQG�LPSDFW�WHVWUHVXOWV�

Page 15: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

)LJXUH����RFWR%R[�SHHO�DQG�VWLFN�GXDO�URZ�RI�JDVNHWV�LQ�D�JURYH�IRU�HDV\�PDLQWHQDQFH�

6XPPDU\7HVW�HQJLQHHUV�IDFH�GLIILFXOW�FKDOOHQJHV�ZKHQ�PHDVXULQJ�0,02�WKURXJKSXW�EHFDXVH�ZLUHOHVVFKDQQHO�HQYLURQPHQW�LV�FRQVWDQWO\�FKDQJLQJ�DQG�UDGLR�RSHUDWLQJ�PRGH�LV�FRQVWDQWO\�DGDSWLQJ�WR�WKHFKDQJLQJ�HQYLURQPHQW��,Q�RWKHU�ZRUGV��ZH�KDYH��WRR�PDQ\�PRYLQJ�SDUWV���PDNLQJ�LW�GLIILFXOW�WRREWDLQ�UHSHDWDEOH�PHDVXUHPHQWV�

7R�JXDUDQWHH�UHSHDWDEOH�DQG�PHDQLQJIXO�UHVXOWV�WKH�WHVWEHG�PXVW�EH�FDSDEOH�RI�FUHDWLQJ�D�YDULHW\�RIZLUHOHVV�FKDQQHO�FRQGLWLRQV�LQ�D�FRQVLVWHQW�PDQQHU��,W�PXVW�DOVR�EH�ZHOO�HQRXJK�LVRODWHG�WR�NHHSLQWHUIHUHQFH�IURP�LPSDFWLQJ�WKH�SHUIRUPDQFH�RI�KLJKO\�VHQVLWLYH�UDGLRV��3DUW���RI�WKLV�DUWLFOH�VHULHVH[SODLQV�WKH�IDFWRUV�WKDW�LPSDFW�0,02�WKURXJKSXW��7DEOH���VXPPDUL]HV�KRZ�RFWR%R[�03(�WHVWEHGFRQWUROV�WKHVH�IDFWRUV�WR�SURYLGH�DQ�HQYLURQPHQW�ZKHUH�GHYLFH�EHKDYLRU�DQG�SHUIRUPDQFH�FDQ�EHUHOLDEO\�FKDUDFWHUL]HG�

7DEOH����+RZ�RFWR%R[�03(�WHVWEHG�FRQWUROV�IDFWRUV�WKDW�LPSDFW�0,02�WKURXJKSXW�

Page 16: Measure throughput of cellular and WiFiMIMO radios · is, for several reasons, a monumental challenge. For example: Modern wireless devices are designed to adapt automatically to

$�ZLUHOHVV�WHVW�EHG�VKRXOG�HPXODWH�D�YDULHW\�RI�FKDQQHO�FRQGLWLRQV��LQFOXGLQJ�PXOWLSDWK��SDWK�ORVVDQG�QRLVH��$W�WKH�VDPH�WLPH��WKH�WHVW�EHG�VKRXOG�EH�FDSDEOH�RI�HPXODWLQJ�D�0,02�FKDQQHO�WKDWVXSSRUWV�PD[LPXP�WKURXJKSXW�RI�GHYLFHV�EHLQJ�WHVWHG��7KH�WHVW�EHG�VKRXOG�DOVR�JXDUDQWHHUHSHDWDEOH�DQG�FRQVLVWHQW�WHVW�UHVXOWV�LQ�ODEV�DURXQG�WKH�ZRUOG�