iPhone4S trap signal door: the mobile frequency band suspected of being castrated by Apple

Before and after the Spring Festival, the Apple iPhone 4S also caused an embarrassment in the industry: During the Spring Festival, Apple's official direct sales shop 4S hard to find, authorized dealers around the country are increasing sales; the first week after the holiday, Unicom announced its own channels Sales of iPhone4S bare metal; other latest rumors that China Telecom will start selling CDMA version 4S next week. In addition, 4S users who use mobile phones broke the news on the Internet and said that in some office buildings using 4S, there will be a phenomenon that the signal is full but they cannot make calls to answer the phone... All kinds of news on this mobile phone make people feel numb, but these "Chaos" is still reflected in Apple's strong dominance, as well as the operator's embarrassment.

One side is the world's most popular telecom operator, while the other is the world's most popular smartphone, but the two nevertheless never come together.

After a long wait, China Mobile's fruit powder users have not only waited for an iPhone supporting TD-LTE, but also encountered a lot of joke from iPhone4S to users. Some users have found that using the mobile SIM card does not properly activate the iPhone 4S, and using the mobile SIM card in the iPhone 4S can sometimes result in a situation where the signal is unstable or the signal is full but cannot be answered.

The above problems have caused great difficulties for China Mobile’s iPhone4S users. What is the reason for this? To this end, the reporter launched an investigation.

Multi-User Encounter Signal Gate On January 19th, a user named "koyota211" posted on Weifeng.com, claiming that the 4S version 5.0.1 (9A406) purchased on the 13th had a signal in the unit and could not normally make and receive calls. In the case of SMS, messages cannot be received, but they are used normally in places other than the unit.

The user stated that he had used 3 national bank 4S tests, one of which was the Unicom contract machine. Through testing, it is found that as long as the 4S enters the coverage area of ​​the EG frequency point, there will be a signal but no call or even a signal, but the call test in the PG frequency coverage area is normal.

According to report, the current mobile network coverage frequency is 885 to 909 MHz for the upstream frequency band, 930 to 954 MHz for the downlink frequency band, with 885 to 890 MHz upstream and 930 to 935 MHz downstream, and each 5 MB bandwidth for the uplink and downlink is the EGSM frequency, that is, the EG frequency band. ~ 909MHz, 935 ~ 954MHz, 19MB bandwidth for the uplink and downlink PGSM frequency coverage area, which is PG frequency.

In fact, the failure of koyota211 is not a single case. Reporter's reporter noticed that many mobile users in various forums and message areas reflected the above problems. In addition, there are users that use the mobile SIM card can not properly activate iPhone4S mobile phone.

Beijing user Yang is one of them. According to him, the licensed 4S that he purchased from the dealer channel could not activate the 4S mobile phone. He had repeatedly moved to the mobile business office to replace the card. None of them solved the above problem. Finally, he could only ask the dealer for a 4S.

According to Mr. Yang, the customer service staff of the mobile business office once told him that currently China Mobile has launched a 4S dedicated SIM card, but at present, it has been piloted in Guangdong, Beijing has not yet arrived, can change the special card after arrival and try again, while waiting for the apple Latest firmware.

On the other hand, netizen koyota211 also found Apple's technical advisor to inquire about the frequency problem. The technician promised him to put together the technical issues mentioned in the above posts, translate it into English, and send it to Apple's headquarters in the United States. The Chinese Engineering Department will also be in contact with China Mobile to jointly solve the problem.

However, Apple's public relations source said that compared with the iPhone4, 4S signal has been very good, the person also denied having discussed with China Mobile to discuss the above issues.

EG frequency band was deleted by mistake?

In fact, according to the existing network layout of operators, the mobile EG band should not be shielded. What is the reason for this?

User koyota211 gave a preliminary conjecture: iPhone4S shielded the CDMA network when it introduced the mainland market, and the frequency of the CDMA network and the frequency of the mobile EGSM network are very close. The CDMA downlink frequency band is 870-880MHz, and the starting value of the mobile uplink frequency band is only With a difference of 5MHz, this 5MHz frequency is likely to be mistakenly deleted. However, the user stated that it is currently impossible to determine whether Apple has removed the CDMA band hardware or locked the CDMA band through firmware.

Koyota211's conjecture was recognized by operators insiders. An insider of the operator told reporters that the 4S mobile phone may enter China to shield CDMA network support and deal with the mobile phone's baseband RF unit. However, this may be due to the inaccurate processing.

The above-mentioned operator insiders pointed out that operators protect their market share through frequency restrictions, and on the other hand, they also restrict competitors.

However, it is not yet possible to speculate whether the shielding of the band is required by China Unicom in cooperation with Apple or Apple's own "mistakes." Yesterday, reporters called Apple and China Unicom, respectively, the above companies declined to comment.

A dealer in Zhongguancun said in an interview with reporters that from the perspective of his understanding, the US version, Hong Kong version, and China Unicom version 4S that he sold all had signs of instability or were unable to make phone calls.

"In the 4S I sold, there were 2 of the 5 units that had the above situation." The distributor stated that the iOS 5.0 version previously sold did not have the above problems, but when it came to iOS 5.0.1, the system appeared unstable, especially Version 5.0.1 (9A405). In order to solve this problem, he could only refresh some of the machines to 5.0.1 (9A406), and the situation improved after brushing.

Earlier media reports said that the US headquarters engineers are upgrading the iOS system and will launch the iOS 5.1 version in the future. The new version will solve incompatibilities.

However, in the view of the operators mentioned above, the most fundamental reason is that Apple's mistakes in the processing of mobile phone baseband RF units resulted. "If Apple does not deal with hardware, will Unicom's Apples be able to turn into telecommunications through firmware updates? China Unicom will not take this risk."

Some experts pointed out that the agencies responsible for network inspection can give technical monitoring reports to determine the problem. If it is really a hardware problem, then Apple may face the risk of product recall.

China Mobile's injuries and injuries Even the powerful company such as China Mobile has suffered an "injury and injury" after meeting Apple. Just like China Unicom’s secretly moving "Guan Gong Riding Trojan" ad, China Mobile's 3G has always encountered the embarrassment of "a hero is useless."

As of now, iPhone4S supports WCDMA/CDMA/GSM three network formats, which means that China Telecom already has the prerequisites for operating iPhone4S, and now the only thing missing is China Mobile's TD-SCDMA.

"There is no clear news that Unicom 4S will be sold and 4S Telecom will be launched soon. However, there is no clear news about the introduction of 4S to mobile TD. If even the 4G of the 2G castrated version cannot operate normally, it will undoubtedly have a relatively large impact on China Mobile's high-end market." Industry insiders who would like to be identified have expressed this.

According to estimates from a dealer in Zhongguancun, there are currently several million iPhone4S in the Chinese market, of which the estimated mobile network usage is no more than 200,000. Therefore, the impact of frequency gates on China Mobile is still relatively small.

However, although the "castrated version" 4S has a technical blind spot, it is not an unresolved method. Xiang Xianggang, CEO of Feixiang.com, disclosed to reporters that mobile can completely solve this problem by testing and changing its EG frequency to PG frequency.

In fact, since China Unicom's successful introduction of the iPhone 4 at the end of 2010, the loss of high-end users of China Mobile has been severe, and global brands have suffered a full blow. Creating star terminals that are attractive enough has also become a problem that China Mobile must solve. Based on the various advantages of the iPhone, China Mobile can only sell the iPhone without help, although these users' machines do not support China Mobile's TD network.

Fu Liang, a communication expert, believes that due to the imperfections of the TD-SCDMA industry chain, China Mobile’s 3G terminal growth has been in adversity. Although terminal manufacturers have hinted that they will strongly support the growth of TD handsets, they are less than words, leading to mobile 3G mobile phones. Insufficient competitiveness. "For the troubled China Mobile, it is necessary to step up planning for the development of 3G and 4G and step up the launch of star products."

User koyota211 gives a preliminary guess:

iPhone 4S shielded the CDMA network when it introduced the mainland market, and the frequency of the CDMA network and the frequency of the mobile EGSM network are very close. The downlink frequency band of the CDMA is 870-880 MHz, which is only 5 MHz lower than the initial value of the mobile uplink frequency band. This 5 MHz frequency is very high. May be mistakenly deleted.