In recent years, be in China as brand of Chinese mobile phone the market and international market are strong rise abruptly, the competition of smartphone domain was entered turn white-hot. But the maturity as a result of chip and hardware technology, mobile phone function more and more hasten is the same as, performance data is more and more similar also, the poor dissimilation between mobile phone brand is more and more difficult. In the meantime, new character and run cent parameter causes aesthetic exhaustion easily to consumer. Accordingly, consumer values the user experience of the mobile phone, stability and wear more and more. Accordingly, whether offer first-rate user experience and reliable quality continuously, become future of mobile phone brand whether successful key.

 

Today’s smartphone is simple communication tool no longer, however one lets people can connect net, job and —— of platform of recreational individual operation at any time and place and Internet join, it is the job and recreational foundation. At present two old techniques can provide network link on the mobile phone, it is the beehive shift network that companion is born as the mobile phone, 2 it is a bit late occurrence Dan Fei the IEEE 802.11 of fast development is wireless sth resembling a net of local area network (WLAN)—— more is with Wi-Fi this name is used. 802.11 technologies work is in avoid accredit (Unlicensed) frequency paragraph, have cost low, rate tall, deploy is simple and enclothe wide characteristic. The circumstance waiting in interior of family, bazaar, hotel, enterprise and public facilities is an user receive take the first selection kind to Internet. According to statistic, on the mobile phone, the data flow of user use Wi-Fi is ambitious the data flow that generates at using beehive communication technology.

Mobile network and Wi-Fi discharge are had rate quite. Stationary / Wi-Fi discharge surmounts stationary since 2018 / wired (Wired) network discharge (origin: Cisco)

 

Because Wi-Fi component bore the weight of,the data flow with smartphone most user is mixed use time, the use that with quality land of very old rate is affecting an user experiences the function of Wi-Fi component. However, because brand of a few mobile phones takes seriously not quite to Wi-Fi component quality, the user experience that brings about a mobile phone and brand are approbated degree reduce continuously. Among them, wi-Fi signal weak, online speed slow, defer is advanced a few big questions got more user is complained, brought negative effect to the figure of these mobile phone brands. Accordingly, how to improve the quality of mobile phone Wi-Fi, become the issue that each manufacturer takes seriously urgently. The article tries from technical angle, because answer,the matter that discusses quality of Wi-Fi of influence mobile phone deep reachs his method, announce complete Wi-Fi checks the importance to the smartphone.

 

 

The user passes through the Wi-Fi icon that examines upper part of mobile phone screen, what can understand current Wi-Fi signal directly is strong weak. Occasionally the mobile phone of two different brands is in obviously same position, indication signal division number is different however, then the user can complain signal case counts difference of little signal of mobile phone Wi-Fi. The function of this and receiver of mobile phone Wi-Fi is concerned. Wi-Fi component is in with the road by implement below join condition, radio frequency (RF) receiver can be measured regularly receive take a place (the broadcast that AP) gives out seals a bag, cipher out is wireless receive signal strength (RSSI) , the size that is worth according to RSSI again, lose by force in what signal shows on the operating system. Below normal circumstance, the mobile phone is apart from a road by implement closer, RSSI cost is higher, state the Wi-Fi signal that receives is stronger; The mobile phone is apart from a road by implement further, RSSI is lower, state Wi-Fi signal is weaker.

 

Through calibration and had checked mobile phone, measure gotten RSSI value and signal division number and receive signal intensity truely to agree, to the reception of signal of be issued to lower levels performance also has been compared. And the mobile phone that checks without crossing calibration, RSSI value and signal division number and receive signal truely abhorrent, the reception to signal of be issued to lower levels performance is poorer. Accordingly, the mobile phone Wi-Fi that did not undertake receiver calibration checks shows signal is weak not only, the limits of online speed and job should need the mobile phone that checks at classics calibration, the place that often receives Wi-Fi signal quite in normal hand function shows however without signal, bring about an user to experience not beautiful.

 

The mobile phone that another kind of circumstance is the person that use can see the Wi-Fi signal of one case above obviously occasionally, effective online rate is very slow however, even form break a string together, user experience is affected badly. The mobile phone shows signal explains receiver does not have a problem, so does the problem go where? The answer is on the catapult power of the mobile phone. To the mobile phone, very important —— projects catapult power power is exorbitant, can make report of mobile phone bad news too fast, need charges often. And emissive power is too low, can make go up the road cannot be reached normally after signal passes method attenuation by implement receving antenna, reduced the real work scope of the mobile phone thereby. Accordingly, in production process of mobile phone production, must launch power to have strict calibration and test in the light of Wi-Fi, launch the accuracy of power in order to ensure.

 

Because wireless communication is two-way, through Wi-Fi of machine of the adversary in producing production course emissive power and receiver sensitivity have strict calibration and test, can ensure of the mobile phone go up link (Uplink) and link of be issued to lower levels (Downlink) maintains inside limits of the biggest job match, and won’t appear the circumstance of among them lug hind leg.

 

The catapult of the smartphone and receiver are undertaking calibration test around is compared

 

The 3rd kind of circumstance, because Wi-Fi main job is in,avoid accredit frequency paragraph, spectrum is more crowded, the user that has experience so often can choose the road by implement switch arrives the specific frequency with lesser interference. But use different frequency to receive when user mobile phone take a route by implement when, can discover signal intensity can have with online rate sometimes drop apparently. Because Wi-Fi job is in,this is two main frequency paragraph, 2.4GHz and 5GHz. Every frequency paragraph fractionize is many frequency, like 2.4GHz frequency paragraph have can use frequency to 14 of 2484MHz from 2412MHz, and 5GHz frequency paragraph because bandwidth is wider, have distributing to arrive in 5180MHz 24 frequency inside 5825MHz limits. To component of mobile phone Wi-Fi, different frequency paragraph the RF property performance of usable frequency inside limits can have very big different. Because this is when manufacturing test process is medium, should right these two frequency paragraph the many frequency inside are ordinal have calibration and test, all in 2.4GHz and 5GHz frequency after ensuring the mobile phone leaves factory thereby can be run normally.

 

 

Discuss online career next. Wi-Fi regards a kind of wireless local area network as technology of subsidiary channels in the human body through which vital energy, enclothe limits to cover range as beehive mobile, terminal position is secured relatively normally. So, the frequency of located and wireless channel mixes Wi-Fi signal optionally the beehive network that dimensional orthogonality sex wants excel to be enclothed extensively. Accordingly, wi-Fi can use tall bandwidth and the dominant position of many aerial technology effectively, promote rate considerably. At present the product of 802.11ac Wave 2 of market main trend can have supported be as high as 160MHz bandwidth and much user – much input is outputted more (MU-MIMO) technology. With be being connected high (floating platform of 835/836 of Qualcomm) brave dragon is exemple, it is supportable 802.11ac 2×2 MU-MIMO, before transmission rate is compared, acting product promotes one times above. And floating platform will support prospective mobile phone taller bandwidth and more MIMO antenna number.

 

However, if producing the neglect in production process new to these character has a test, bring about a product probably to appear in be used actually the problem with online slow rate. For example, a lot of inchoate test instruments support 80MHz only or the generation of bandwidth signal reconciles under 40MHz tone, bring about high speed of the part in producing a test to lead mode to fail to have a test, accordingly we cannot be informed a product to fall to whether be put in quality problem in high rate mode, and will exist after the product appears on the market quality risk. Although a few manufacturers adopt the method of spectrum joining together to obtain the catapult of module of mobile phone RF to check a result, but because was used,be not real time sampling (cent second pick take) , such result cannot reflect the real character of signal well and truly, put in the error of certain level. The wireless communication instrument that passes through newest generation (be like LitePoint IQXel-MW) , support the signal demodulation of 160MHz and generation, can lead mode to have complete test to these high speed.

 

And the issue that also is put in likeness to the test of MIMO, because inchoate instrument has analyzer of signal of a vector only mostly / vector signal generator (VSA/VSG) combination, because this is same,time can is opposite only link of a RF undertakes test and verify. Be aimed at the mobile phone that supports MIMO, the means that can use time-sharing switch only is ordinal to each RF link test and verify. The firm that uses this kind of method cannot is informed wait for measure content (DUT) job is behaved in the real property of MIMO mode. Through wait for new wireless communication instrument like IQXel-MW, can support synchronism of passageway of MIMO of most 4~8 road to check, the function of link of mobile phone RF below implementation MIMO setting checks.

 

Different bandwidth and the combination that MIMO antenna counts

 

 

There are a few new popular applications on Internet, for example online game, as a result of sex of its real time and interactive sex, very tall to the requirement of network latency time. Defer is lower, game experience is better, defer is taller, game experience is poorer, even cannot normal play. Accordingly, defer is a when evaluate a smartphone to link net performance main indicator. The cause that causes delay has a lot of. Because IEEE 802.11 is the job,in the media under TCP/IP agreement the visit is controlled (MAC) layer and physical layer (PHY) agreement, used multichannel of monitor of “ carrier wave to access / collision detects the conflict of ”(CSMA/CD) avoids a mechanism. Accordingly, as a result of,the defer of Wi-Fi wireless network basically is quality of mobile phone signal not the interference that beautiful perhaps comes from other Wi-Fi device is caused for many times pass again cause. Nevertheless, the receiver performance of the mobile phone is bad to also be met those who bring about be issued to lower levels is heavy pass increase.

 

The main indicator that assesses quality of transmit of mobile phone Wi-Fi is error vector extent (EVM) . EVM mirrorred attune of IQ of signal of mobile phone catapult to change the degree that deviate ideal is worth. EVM is taller, signal quality is poorer, repass is wireless after the attenuation of the passageway, road by implement receiver is very difficult normal demodulation this signal, cause the involuntary discharge of urine that seal a bag to become estranged to be passed again, lengthened transmission defer thereby. Accordingly, the signal quality that we expect to launch end in the mobile phone as far as possible good, ability ensures transmitted stability and low defer. In production process of mobile phone production, we use the RF signal that catapult of machine of VSA instrument adversary issues to undertake demodulation is analysed, can calculate an EVM value.

 

Because EVM is worth the noise function that reflective is RF link, so if the noise layer that checks an instrument (Noise Floor) is exorbitant, add with respect to meeting alternate wait for the accuracy that measure signal and affects EVM to measure an outcome. Generally speaking, the noise layer of the instrument wants the 10dB left and right sides that asks under EVM standard. For example, the EVM of 11ac 256QAM signal asks cannot prep above – 32dB, a confusion of voices of VSA believes a need under – 42dB ability gets relatively accurate EVM measures an outcome quite. And the air that the 802.11ax standard of next generation asks to support 1024QAM runs, EVM must be achieved – 35dB. The EVM of afore-mentioned IQXel-MW can be achieved – 48dB is the following, have the surplus of 13dB above at the requirement of 11ax relatively, because this can measure these high-ranking attune accurately,change the EVM value of signal. Besides EVM, error of frequency of symbol of frequency sum of errors also is the main indicator that judges quality of signal of mobile phone Wi-Fi, must use test instrument to have a test to these two finger.

Diverse mix runs the EVM index requirement of rank number

 

A when Wi-Fi signal disturbs each other between the mobile phone main reason is the interference between photograph adjacent passageway. Because photograph adjacent passageway is divulged,this interference basically is cause; Photograph adjacent passageway is divulged than (the energy proportion that ACLR) reflected signal of mobile phone catapult to divulge photograph adjacent channel. This proportion is higher, the interference of mobile phone signal in working to other frequency is bigger. If the photograph adjacent passageway of the mobile phone is restrained not beautiful, the interference that causes to the environment is met very big, of whole network pass again because of,meet this grow in quantity, cause defer to increase to be reduced with transmission rate. 802.11 standards basically pass through transmission spectrum screen (the spectrum function of signal of machine of adversary of Transmit Spectral Mask) undertakes assessment. Through support transmission spectrum screen tests test equipment of the function, this index that is aimed at a mobile phone undertakes assessment, ability ensures the product reduces the interference of pair of photograph adjacent passageways as far as possible in real work.

 

The receiver function of the mobile phone is very main also to defer, a good receiver can receive the data that issues remotely correctly to seal a bag. If admit failure, can cause pass again and data rate falls, produce bigger delay thereby. The method that evaluates receiver performance basically is give out diverse mix to change by the VSG of test gear encode mechanism (the Wi-Fi standard signal of MCS) , lead through the mistake sealing a bag that measures mobile phone receiver (the function that PER) will come to judge receiver. To VSG, the requirement supports bigger dynamic range, and also have higher demand to noise layer.

 

 

Today, the smartphone is almost indispensable in our life, each big smartphone brand still is undertaking the technology is innovated ceaselessly. But no matter the smartphone increases what kind of new character and new function, among them Wi-Fi component still is bearing the weight of most network discharge. Accordingly, the function of Wi-Fi component and the brand self-identity of the use experience that quality is affecting smartphone user and smartphone are spent. The article analyses the common Wi-Fi quality problem in the smartphone from technical angle, the cause of formation that waits like signal intensity, rate and defer; If why producing the implementation in production process,from the test at the same time angle provides mobile phone manufacturer complete and accurate test method, make thereby mobile phone course of study person can reduce these quality problems as far as possible.