[introduction]Wi-Fi and 5G are to promote nobody to drive the car develops prompt a factor. Spectrum interference can drive to car and passenger safety causes adverse effect, accordingly of these technologies work in coordination and coexist means still is a challenge. Article discussion supports car connective technology, and how does solution of select-high sex filter answer V2X and Wi-Fi coexistence to challenge, correspond in order to realize car.

 

Wi-Fi and 5G are to promote nobody to drive the car develops prompt a factor. Spectrum interference can drive to car and passenger safety causes adverse effect, accordingly of these technologies work in coordination and coexist means still is a challenge. Article discussion supports car connective technology, and how does solution of select-high sex filter answer V2X and Wi-Fi coexistence to challenge, correspond in order to realize car.

Car connective foundation

To let true nobody drive the navigation below the circumstance that the car intervenes in nobody, must mix with other vehicle all round the data that infrastructure lasts to share all types in real time.

This will is opposite through the car everythings on earth (V2X) communication system comes true. V2X includes a car to the car (V2V) , vehicle is right infrastructure (V2I) , vehicle is right network (V2N) and vehicle are right pedestrian (V2P) corresponds.

V2X is a foundation with technology of communication of 5.9GHz special stone’s throw, apply to fast and mobile object. Although be below condition of blame line of sight, it also can establish reliable radio link. This kind of authentic link makes the driver can realize state of ahead occurrence danger, reduce potential car collision and casualty accidents thereby.

In addition, be about to appear to traffic has the warning that block up and offer optional course proposal through giving out, v2X can raise the whole world to carry efficiency, reduce carbon dioxide discharge capacity, still can reduce car to uphold requirement at the same time.

Because V2X can be C-V2X (the vehicle that is based on beehive technology is right everythings on earth) , use beehive technology to establish direct communication link namely, also can be DSRC (special short be apart from communication) , it is a foundation with IEEE 802.11p standard namely, and once was technology of exclusive practicable V2X, come true so nobody drive the total latent capacity of the car is more complex.

However, different car manufacturer and country / the area supports a kind or another kind of standard, however, can use identical spectrum to solve same problem, and OK and concomitant.

Understand join technology

To understand concomitant challenge better, the technology that we must involve in understanding car join and its function (graph 1) . Because every kinds of technology has his own character, so they can alternant and the performance that won’t reduce other technology.

Graph 1: Car join technology

These technologies include:

• The V2X that uses at automobile safety (DSRC and C-V2X) : Infrastructure of V2X general and car, roadside and whole annulus condition have communication, in order to enhance security, found to drive automatically method.

• Apply to the 4G/5G cloud join that car OEM serves: 4G/5G join application can include to be diagnosed remotely move with monitoring car, the software in taking line space is updated, carry out long-range operation and hold those who accuse to share is automatic drive motorcade.

• Can bring 4G/5G cloud connective the experience inside the car: Driver and passenger can use this kind of join to enjoy the experience inside brand-new car, include to be based on system of entertainment of the navigation that enhances reality, backlash and music to shed media service to wait.

• Can offer the experience inside high grade car and the Wi-Fi that car dealer serves: Driver and passenger can enjoy a lot of buildup that are based on Wi-Fi the experience inside the car. For example: The efficient Wi-Fi join of whole car is supportable freeboard Qing Dynasty (UHD) video circulates be defeated to many indication screen, support compatible equipment and wireless reserve photograph the screen mirror that resembles a head. Wi-Fi still can support car dealer service, implementation is registered automatically, diagnostic data is transmitted and software is updated.

• Bluetooth? : Driver and passenger can broadcast high fidelity music through blue tooth, still can enjoy a few economic services, if use the smartphone as remote control key.

• SDARS (broadcast of satellitic number frequency serves) : Through serving to join with the radio that is based on a satellite, no matter car is used person where be, can receive the radiobroadcast that love repeatedly.

The coexistence of 5G and LTE is challenged

Through understanding the function of all sorts of technologies / advantage, we can understand concomitant challenge better, mix with 5G especially the compatibility of LTE.

5G (technology of beehive of the Five Dynasties) can raise data rate, reduce delay and increase the flexibility of wireless service. 5G spectrum cent is 6 GHz the following spectrum and millimeter wave.

Wi-Fi moves below 2.4GHz, 5.2GHz and 5.6GHz spectrum, and 2.4GHz Wi-Fi must be mixed with LTE B40 B41 frequency paragraph concomitant. The 2.4GHz of data rate prep above of 5GHz Wi-Fi, because,this is 5GHz frequency paragraph bandwidth is bigger, can bind more channel together. This means radio frequency engineer to must use right filter product (be in namely photograph adjacent frequency paragraph in have enough attenuation property, the reception that has come true sensitivity) , make full use of thereby wider frequency paragraph.

Graph 2: V2X and 5GHz Wi-Fi are concomitant

Should drive automatically when the passenger in the car uses 5.6GHz heat, 5.6GHz Wi-Fi and V2X (graph 2) coexistence makes another challenge. The only way that realizes link of reliable V2X radio ensures namely relatively low receiver sensitivity deterioration. Use the proper filter solution that offers the attenuation outside ample area in 5.6GHz Wi-Fi only, just achieve this one goal likely (graph 3 with the graph 4) .

High-powered filter wave solution — why LTCC is not enough

More and more function array increased the amount that radio differs in the car, nowadays, a car is had amount to 5 radio (namely V2X, 4G/5G, Wi-Fi, blue tooth, SDARS) . This means many radio to send and receive implement each other are stood by, in different frequency paragraph in move. If the emissive power of catenary of a RF exceeds the signal power level that around receiver receives, can produce receiver sensitivity problem.

Concomitant filter conduces to reduce these ” interference signal ” the interference of generation, avoid receiver sensitivity problem and the problem that do not accord with code thereby. However, the filter that is not all claiming that have concomitant function suits this application. For example: Graph 3 compared B47 body sound wave (BAW) filter and low temperature burn pottery and porcelain in all (the function of LTCC) broadband filter and systematic impact.

Graph 3: QPQ2200Q and LTCC undertake comparative: Broadband function.

… nowadays, a car is had amount to 5 radio…

LTCC can filter only broadband frequency. B47 BAW filter is had insert loss similarly with LTCC filter, but have frequency of taller 5GHz UNII 1-3 paragraph control function. B47 BAW filter can replace LTCC filter in Tx/Rx method, or place only in Rx side. Graph 4 explained how LTCC filter doesn’t restrain UNI-3 frequency paragraph, and how to mix to UNII-2 UNI-1 frequency paragraph provide poorer curb system.

Graph 4: QPQ2200Q and LTCC undertake comparative: B47 BAW filter can restrain frequency of 5GHz UNII 1-3 paragraph

Next, we compare LTCC and B47 V2X concomitant filter from system and implementation angle. Graph 5 compared implementation 1, the V2X that place of link of 000 meters of V2X needs and Wi-Fi antenna are kept apart. The V2X system that Zun Tu shows (TCU + active antenna) there is filter of a LTCC only on Tx method, ask the antenna that is more than 80dB is kept apart right now, this comes true possibly in practice hard quite. The V2X system that right graph shows has concomitant filter of a B47 V2X in TCU, come true 1, link of 000 meters of V2X, need the active antenna that 15dB antenna keeps apart only. If design / systematic engineer can realize the aerial segregation that exceeds 20dB, so they may need to install concomitant filter of a V2X in active antenna only. Besides the Wi-Fi inside the car, still need to consider another use case when deciding filter solution, namely whether is car had new the Wi-Fi function that introduce. That is to say, aerial keeps apart the decision of heat of mobile phone Wi-Fi that uses by the passenger.

Graph 5: Realize the V2X that place of reliable V2X link needs and Wi-Fi antenna segregation: QPQ2200Q B47 and LTCC undertake comparative.

The filter product of Qorvo uses the BAW technology that already won patent, can satisfy complex alternative requirement through optimizing, standard frequency limits comes for 1.5GHz 6GHz. For example: Qorvo QPQ2200Q filter is global head money is solved drive automatically the filter of the V2X in the car and 5.6GHz Wi-Fi concomitant problem. Another give typical examples is filter of Qorvo QPQ2254Q 2.4GHz Wi-Fi, its design supportive Wi-Fi 2.4G and LTE B40 and B41 to coexist at the same time. The size of these filter is smaller than filter of pottery and porcelain, rose to design flexibility thereby.

However, even if BAW belt connects filter to also cannot solve the concomitant problem in V2X environment completely. We still must consider the main effect that defect wave filter produces. Outside taking a filter to be able to provide ample area, restrain of above paragraphs discussion, and the filter of QPQ2230Q defect wave of Qorvo but ” eliminate ” 5GHz Wi-Fi method is in the Rx frequency of V2X paragraph the noise of generation, prevent Rx frequency thereby paragraph noise coupling arrives in V2X system, cause sensitivity deterioration problem, if fasten all calculator (graph 6) in be shown. Graph 7 show, if defect wave filter was not used on 5GHz Wi-Fi method, the sensitivity deterioration that is as high as 18dB can appear in V2X receiver, and use BAW technology dominant position and the defect wave filter of elaborate design, its sensitivity deterioration is almost 0.

Graph 6: Filter of V2X defect wave is contained on 5GHz method (the Wi-Fi front of QPQ2230Q) .

Graph 7: The Rx frequency when use and using filter of QPQ2230Q defect wave paragraph noise and sensitivity deterioration.

The key that another need takes seriously highly is challenged even if, v2X need and electron collect fees (ETC) is concomitant. Right now problem depends on, ETC spectrum (Europe is 5795-5815MHz, china is 5790-5800MHz UL, 5830-5840MHz DL) be close to V2X spectrum too (North America and Europe are 5855-5925MHz, china is 5905-5925MHz) , if pursue 8 in be shown.

Graph 8: Global ETC spectrum and V2X are concomitant.

A kind of method that solves this problem uses the filter with reasonable design to come on V2X method namely eliminate ETC spectrum. Let us understand European situation. Graph 9 compared the spectrum that input end is used and does not use defect wave filter in V2X FEM to divulge. The spectrum that Zun Tu shows to PA outputs end is divulged cannot ask through ETC norms (- 65dBm/MHz) , because this V2X cannot coexist with ETC, unless be in ETC radio, the method that perhaps adopts avoid of a few software solved this problem. Right graph shows, if the defect wave filter of elaborate design was inserted in V2X radio, criterion V2X can coexist with ETC.

Graph 9: Europe: Spectrum divulges pattern plate to undertake comparative, use and do not use filter of ETC defect wave.

Now, the spectrum state that the country takes a fancy to in light of us (graph 10) . From inside Zun Tu we can see, ETC cannot coexist with V2X, unless this problem was solved in ETC radio. When right graph showed the filter that uses elaborate design in V2X radio, accord with ETC norms to ask (- 65dBm/MHz) and abundant capacity is sufficient.

Graph 10: China: Spectrum emissive screen undertakes comparative, use and do not use filter of ETC defect wave.

Token is high-powered two parameter of filter product are resonator quality, namely quality factor (Q) and coupling factor (K2) . Utmost decreases insert loss to need tall Q value, and the bandwidth with tall K2 broader support. The technical progress of resonator level conduces to improvement inserting loss and alternative function, the filter product that makes bandwidth wider is OK move below the frequency condition that is as high as 6GHz.

Conclusion

Tall Q belt connects filter and defect wave implement combination can is drive automatically the concomitant challenge in car design offers the most complete solution. The data that discusses above the basis, LTCC filter is not true concomitant filter, in Wi-Fi and V2X each other act well far from in the distinctive car environment of adjacent.

Know filter and solution of defect wave filter through using advanced BAW to take, can implement all technologies on spectrum of car couplet net without seam coexistence, the mobile world that ensures we expand increasingly thereby more on the safe side, have life fun more.

(origin: Qorvo semiconductor, author Ali Bawangaonwala, manager of Qorvo advanced sale)

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