The first part of the introduction
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With the development of mobile communication technology and the popularity of mobile data services and terminals that can carry data services, competition based on traditional voice services is no longer the focus of mobile telecom operators; a variety of value-added operations running on mobile data platforms Business has become a magic weapon for mobile operations to improve their competitiveness. Despite the collapse of the IT bubble in the global stock market, the construction of 3G mobile networks and the launch of 3G services have been greatly delayed, and telecom operators are still actively seeking appropriate solutions; they are pursuing high-speed mobile digital networks and reducing the cost of network construction. Looking for a compromise, the compromise result is that 2.5G network technology (CDMA1X and GPRS), which can be better compatible with 2G networks, has been adopted in the world in the past two years, and the corresponding value-added services on 2.5G networks have also been obtained. Rapid development.
In China, with the establishment of CDMA1X and GPRS networks, a variety of business needs based on 1X and GPRS data networks have emerged. These include Internet services, mail receiving and dispatching services, MMS services, GPS services, mobile VOD services, mobile MOD services, videophone services, and VideoEMAIL services. We believe that mobile VOD services and video telephony services are the services that best reflect the value of CDMA1X networks, while Mobile MOD (Music On Demand) and enhanced video MMS services (VIDEOMAIL) can best reflect the existing features of GPRS.
The second part of the technical background
Let's briefly review the current state of several key technologies involved in our approach.
1,2.5/3G mobile data network
At present, China Unicom is actively promoting various applications on the CDMA1X network. It can be expected that a large number of mobile broadband network-based applications will emerge along with the CDMA1X data network. As a typical 2.5G technology, CDMA1X has greatly improved the network transmission bandwidth. China Unicom claims that the peak download speed of CDMA1X network can reach 144Kbps; the test shows that in the case of good signal, the average download speed of CDMA1X terminal It can reach 40Kbps to 80Kbps. Another test shows that under normal circumstances, the upload speed of CDMA1X can reach 32Kbps. Obviously, CDMA1X network has great application potential.
China Mobile's GPRS network has also been built. Mobile claims that GPRS maximum download speed can reach 40Kbps. Our test shows that its average download speed can reach 20Kbps. The advantage of the mobile GPRS network is that it has a wide range of coverage and can support a wide variety of terminals.
Telecom operators claim that peak download speeds will be 2 Mbps in future 3G networks. The industry expects the Chinese government to approve at least two 3G licenses by 2005.
However, compared to 2.5G networks in Europe, the United States, Japan, South Korea and other developed countries, China's 2.5G network has great limitations. The main performance is that the average transmission bandwidth is low. The transmission bandwidth of CDMA1X is only 1/2 of that in developed countries. The transmission bandwidth of GPRS is only 1/3 of that in developed countries, and the stability is poor. This situation has caused domestic 2.5G data services to be monotonous and difficult to popularize. It is difficult to directly copy the mature models and technologies of foreign value-added services based on 2.5G networks to China's 2.5G networks. This provides us with tremendous opportunities and challenges.
In summary, we have entered an era in which mobile bandwidth can initially carry multimedia services. Intense market competition is imperative for mobile multimedia services. The limitations of China's 2.5G network will make mobile multimedia compression technology and streaming media transmission technology play a more important role in the promotion and application of mobile data services.
2, multimedia coding technology
We have noticed that multimedia coding technology has been used in an unprecedented way in the last decade. The popularity of VCD and DVD series products in China is a concrete manifestation. In order to transmit better quality video and audio content under the same network conditions, we need to introduce better image and sound coding techniques. We believe that the MPEG-2 encoding standard, H.263 standard and MEPG-4 SP encoding standard widely used in current VOD systems do not work well in the current Chinese 2.5G network environment; the newly completed H.264 standard has The main reasons for the widespread application of 2.5G mobile networks in China are:
1) The compression performance of H.264 is 3 times higher than that of MPEG-4 SP and 2 times higher than H.263++. The advantage of H.264 is more obvious under low bandwidth. Compared to foreign mobile video coding (such as PacketVideo), the MPEG-4 SP standard is widely used. The compressed image output by our H.264 encoder is more than doubled in bandwidth requirements of the same quality, so that our video stream is in China. The smoothness and clarity of running on mobile networks is far superior to current solutions abroad.
2) H.264 introduces anti-error function in encoding, which is most suitable for noisy wireless transmission environment.
3) In terms of speech coding, G.722.2 is the first wideband audio coding standard that can be operated in a mobile environment. Its sound quality is significantly improved compared to GSM and traditional CDMA, and the required bandwidth is basically unchanged. G.722.1 is the first ITU wideband audio compression standard, and at the same rate, compression performance is significantly improved over MP3.
Considering the network status of China's 2.5G and the coding performance of H.264 and G.722, we believe that it is now the best time to promote mobile VOD services and mobile videophone services based on H.264 technology.
3, terminal processing technology
We know that the requirements for terminals in multimedia services are higher than those for traditional services. In a mobile environment, this contradiction is more prominent due to power consumption limitations. However, in recent years, chip manufacturers have made significant progress in low-power, high-performance processors. Intel introduced the high-frequency XScale series of mobile CPUs with Wireless MMX enhancements. And more and more PDAs and mobile phones based on Xscale and Microsoft WinCE series operating systems. TI's OMAP CPU also shows powerful processing power in the mobile space. This year, there will be five to seven mobile phone manufacturers in China that will launch PDAs or SmartPhones using the above CPUs and operating systems.
In addition, traditional mobile phone manufacturers like Nokia's new mobile phones have begun to adopt more powerful processors and have more memory. Internet access and support for MMS services have become the basic configuration of mainstream mobile phone models.
Therefore, smart multimedia mobile terminals that are becoming mainstream can support the mobile VOD and mobile videophone services that we are going to launch.
The third part of the business description
According to the characteristics of China 2.5 network, combined with the advantages of our own technology and system solutions, we have launched a mobile VOD, enhanced mobile video mail, mobile video phone system solution for CDMA1X network. On the GPRS network, mobile audio on demand services and mobile video mail services were launched. Below we give a detailed description of these businesses.
First, the mobile VOD program
1. Service Description The basic business process of a mobile VOD service is:
1) The terminal browses the program directory,
2) Select content that needs to be on demand. The program directory includes real-time program streams (such as TV news) and non-real-time program streams (such as movies).
3) The terminal sends the selected program number to the server to make an on-demand request, and the on-demand request can also select the play mode, and then the terminal waits to accept the program stream.
4) The server receives the on-demand request number, obtains the program data stream to be transmitted from the video database or the real-time program source, sends it to the cache, and then transmits the program content to the terminal.
5) The terminal receives and decodes and plays the program content in real time, and can be saved on the terminal when needed.
The mobile VOD system can meet the needs of mobile users to understand instant video news and learn about the latest entertainment information.
2, system structure The structure of the entire system is shown below
The description of each function module is as follows:
1) The software installed on the terminal by the terminal system can browse and select the program source, can accept the streaming media of the server in real time, and decompress the video and audio data stream in real time and display and play it on the terminal.
2) The VOD directory server is responsible for responding to the user's login request, querying the location of the program in the database, notifying the stream server of the terminal information and program location, and making the necessary statistics.
3) The streaming server stream server is responsible for concurrently transmitting the program content to the terminal, and retransmitting at the breakpoint if necessary.
4) The video database is used to store programs that are already being produced.
5) Real-time video server encodes video and audio programs in real time. 6) The billing server can use different billing modes to perform statistics according to the playing time, traffic, time period and number of times.
3, technical indicators 1) number of concurrent users: 30,000 concurrent users, 500,000 registered users.
2) Response speed: less than 5 seconds 3) Data transmission bandwidth: 48Kbpss to 100Kbps per channel on CDMA1X, 16Kbps to 32Kbps on GPRS.
4) Maximum program length: less than 60 minutes 5) Video quality: Image size QCIF, frame rate from 5 frames to 15 frames 6) Audio quality: The audio quality is better than the current CDMA audio quality, and the quality exceeds MP3 on the same bandwidth.
4, running platform 1) Supported terminals: notebook, PDA (iPAQ, ET180), SmartPhone, Nokia 7650, Nokia 3650. Supports XScale-based CPU-based mobile terminals, OMAP-based mobile terminals.
2), supported operating systems: support Pocket PC 2002, 2003, support Symbian, support SmartPhone.
3) Network platform: CDMA1X, GPRS, broadband network.
5, related standards 1) transport protocol RTP real-time media transmission (IETF RFC 2190)
RTSP real-time streaming (IETF RFC 2326)
RTCP Real-Time Media Transmission Control (IETF RFC 1889)
SDP session description (IETF RFC 2327)
2) Video coding: H.264 standard 3) Audio coding: G.722.1 standard, G.722.2 standard
Second, mobile video mail solution
1, the basic business process of mobile VideoEmail:
1) Start recording video and audio clips, encoding video and audio content,
2) The terminal sends a request to the server to send an EMAIL. 3) The terminal simultaneously caches and sends the video and audio content to the server.
4) The server saves EMAIL.
5) The server sends EMAIL to the destination via the Internet.
2, the main technical indicators: video size is QCIF, video frame rate is 5 to 15 frames per second, audio quality is not lower than the phone quality.
Third, mobile video phone solution
1, business description
The basic business process of moving VideoPhone is:
1) The calling terminal issues a call request.
2) The server responds to the request and the server calls the called terminal. Establish a connection between the calling and called terminals.
3) The calling terminal encodes the video and audio data streams in real time and transmits them to the called terminal.
4) The called terminal decodes the data stream. At the same time, the called terminal encodes the video and audio data streams and transmits them to the calling terminal, and the calling party interrupts decoding the video and audio data streams.
5) Apply to terminate the call at either end. Server terminal session.
2, schematic
A videophone system across various networks and terminals is shown below:
system:
1) Various terminals including notebooks, PC computers, PDAs, and mobile phones 2) Interactive visual communication can be performed across broadband and CDMA1X mobile networks.
3, technical indicators.
1) Number of concurrent users: 50,000 simultaneous concurrent users
2) Response speed: less than 5 seconds
3) Data transmission bandwidth: 32Kbps-64Kbps per way
4) Video and audio quality: image size QCIF, frame rate 3 to 15 frames, audio quality is better than current CDMA audio quality
3, related standards 1) transport protocol RTP real-time media transmission (IETF RFC 2190)
RTSP real-time streaming (IETF RFC 2326)
RTCP Real-Time Media Transmission Control (IETF RFC 1889)
SDP session description (IETF RFC 2327)
2) Video coding: H.264 standard
3) Audio coding: G.722.2 standard
Third, customized business for China Mobile GPRS
We have customized two services for GPRS.
1, Music Online Business (Mobile Music On Demand)
The terminal can quickly query the music that you want to order, and then the terminal selects the on-demand program, and the server can be played online after being authenticated. It can also be played online continuously in accordance with the mode set by the user. The quality of its sound is equivalent to AM broadcast.
2, MTV download service uses H.264 and G.722.1 encoding technology to process the data stream size is 1/3 to 1/2 of other similar system code output, which can save users double the transmission time and traffic charges.
3, VideoEmail
A video clip of about 15 seconds can be uploaded via GPRS to a designated E-mail address or mobile device with our client software installed. The terminals it supports include mobile terminals that can support MMS services.
The fourth part concludes
Our goal is to apply the latest video and audio codec and streaming server technologies to include wired broadband and mobile data networks. Extend the successful business model related to video and audio in the broadband Internet to the mobile network, and give full play to the convenience and flexibility of the mobile network. We believe that the business model we develop and the operational system platform will create new service value for mobile operators, value-added service providers, and mobile end users.
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