CN103402229B - A kind of data download method and system - Google Patents

Abstract

The invention relates to a data downloading method and system. Wherein, the data downloading method is used for downloading data from the cellular network, including: dividing the original data to be downloaded into a plurality of original data fragments, performing random linear coding on each of the original data fragments, and obtaining a plurality of encoded fragments; An intelligent mobile device downloads part of the coded fragments of the original data from a content server of the cellular network; the first intelligent mobile device receives from at least one second intelligent mobile device having the coded fragments of the original data through short-distance communication Obtaining the remaining coded slices of the original data at the device, the remaining coded slices and the partial coded slices constitute all the coded slices of the original data; All coded slices of the data are subjected to random linear decoding to recover the original data. The data downloading method and system of the present invention reduce the traffic usage of the cellular network of the smart mobile device.

Description

A data download method and system

technical field

The invention relates to the communication field, in particular to a data downloading method and system.

Background technique

In recent years, smart mobile devices such as mobile phones and tablet computers have widely penetrated into people's daily life, and mobile (cellular network) users are increasingly eager to access the Internet anytime and anywhere. These two factors have led to a surge in the traffic of cellular networks . Cellular network operators predict that from 2009 to 2014, the global cellular network traffic will increase 39 times, and the traffic will reach 3.6 exabytes per month. The demand for bandwidth will far exceed the amount that existing 3G and 4G standards can provide. Therefore, the cellular network will be overloaded, and the quality of service will also deteriorate. In order to alleviate the cellular network congestion problem, researchers and network providers have tried to offload the traffic of cellular network to WiFi-based wireless local area network and piconet (Femtocell). However, these networks have not been widely adopted due to limited coverage and high installation and maintenance costs. Some research work points out that the traffic of the cellular network is highly repetitive, and caching some downloaded content on the base station can reduce the traffic between the base station and the Internet by 40%. But this mechanism cannot reduce the traffic between the base station and the mobile device.

There are many non-real-time applications on mobile devices, such as downloading of popular videos and music files, software updates, etc. Some scholars take advantage of the delay tolerance characteristics of these applications to design cellular network traffic offloading mechanisms. They propose to cache downloaded content on mobile devices and share content through opportunistic communication when mobile devices meet, thereby reducing the amount of data downloaded directly through the cellular network. This type of mechanism is called collaboration based on opportunistic networks. Download mechanism. One can imagine a scenario where popular video content on sites like YouTube and Youku may be accessed tens of thousands of times a day by mobile devices. If these data are all downloaded through the cellular network (as shown in Figure 1(a)), a large amount of bandwidth will be consumed. The cooperative downloading mechanism based on opportunistic network utilizes the opportunistic network formed among mobile devices to perform offloading and downloading, as shown in Figure 1(b). First, the server selectively sends a popular video to some mobile devices. Then, when the mobile devices meet, the mobile device that has the video will transmit the video to its neighbor. Through such opportunistic communication, the video gradually propagates from the first few source devices to all mobile devices. Some recent research works have shown that the cooperative download mechanism based on opportunistic networks can effectively reduce the traffic overhead of cellular networks.

However, the existing collaborative downloading mechanisms based on opportunistic networks simply assume that the amount of data to be downloaded is small, transmit the content as a whole during the data distribution process, and consider that the content can be completely retrieved at any one encounter. ground transmission. These assumptions may have been true in the past, but due to the increasing data size of various popular content on the Internet in recent years, these assumptions have become unreasonable. For example, in 2010, the average size of the most popular video clips on YouTube per day was over 10MB. As another example, in 2012, the average size of the top 20 most downloaded software on iTunes was close to 300MB. Taking Bluetooth 2.0 as an example, its maximum throughput is 100KB/s, and it takes at least 5 minutes to transmit 30MB of content. On the other hand, due to the mobility of people and the short-distance characteristics of wireless communication technology used in opportunistic networks, the duration of each encounter between people is relatively short. By analyzing the encounter data between the mobile devices of the participants in an international academic conference, it was found that 60% of the encounters lasted less than 8 seconds, and nearly 80% of the encounters lasted less than 2 minutes. Combining the realities of the above two aspects, it is not difficult to see that the existing assumptions of cooperative downloading mechanisms based on opportunistic networks have become untenable. Therefore, in practical applications, existing cooperative download mechanisms are difficult to achieve their claimed performance.

Contents of the invention

The technical problem to be solved by the present invention is to provide a data download method and system to reduce the data flow of the cellular network.

In order to solve the above technical problems, the present invention proposes a data download method for downloading data from a cellular network, including:

In step a, the content server of the cellular network divides the original data to be downloaded into multiple original data fragments, performs random linear coding on each of the original data fragments, and obtains multiple coded fragments, and each coded fragment contains all Partial information of original data fragmentation;

Step b, the first smart mobile device to download the original data downloads part of the encoded fragments of the original data from the content server of the cellular network;

Step c, the first smart mobile device obtains the remaining coded slices of the original data from at least one second smart mobile device having the coded slices of the original data through short-distance communication, and the remaining coded slices slices and the partial coded slices constitute all coded slices of the original data, the second smart mobile device downloads and stores the partial coded slices of the original data from the content server of the cellular network in advance, and the first The part of code fragments downloaded by the second smart mobile device is different from the part of code fragments downloaded by the first smart mobile device;

In step d, the first smart mobile device performs random linear decoding on all coded slices of the obtained original data to recover the original data.

Further, the above-mentioned data downloading method may also have the following characteristics, step b includes:

Suppose the total number of original data fragments of the original data is M, m is the number of original data fragments downloaded by the first smart mobile device, T is the preset total download delay, and T' is the remaining download time;

Judging whether the actual download progress is less than the expected download progress, the actual download progress is equal to the ratio m/M of m and M, and the expected actual download progress is equal to the ratio T'/T of T' to T;

If it is smaller, then download a coded fragment of the original data from the content server of the cellular network, otherwise no longer download the coded fragment of the original data from the content server of the cellular network.

Further, the above data downloading method may also have the following characteristics, step c includes:

When the first smart mobile device and the second smart mobile device are within the short-distance communication range, receive the coded fragments of the original data sent by the second smart mobile device, and send the coded fragments to the second smart mobile device The device sends its own encoded fragments of the original data, and the number of encoded fragments received by the first smart mobile device is equal to the number of transmitted encoded fragments;

The first smart mobile device judges whether the received coded slice sent by the second smart mobile device is linearly independent from the coded slice it already has, and if so, continues to exchange coded slices with the second smart mobile device , otherwise stop exchanging coded fragments with the second smart mobile device.

Furthermore, the above data downloading method may also have the following feature, the data volume of the original data fragments is smaller than the preset fragmentation volume threshold.

Further, the above data downloading method may also have the following features, in step c, the short-distance communication is Bluetooth communication or WiFi communication.

In order to solve the above technical problems, the present invention proposes a data download system for downloading data from a cellular network, including:

Fragmentation and encoding module, used to divide the original data to be downloaded into multiple original data fragments, perform random linear coding on each of the original data fragments, obtain multiple coded fragments, and store them on the content server of the cellular network , each coded slice contains partial information of all original data slices;

A download module, configured to download part of the encoded fragments of the original data from the content server of the cellular network, and store them on the first smart mobile device to download the original data;

An acquisition module, configured to enable the first smart mobile device to acquire the remaining coded slices of the original data from at least one second smart mobile device having the coded slices of the original data through short-distance communication, the The remaining coded slices and the partial coded slices constitute all the coded slices of the original data, and the second smart mobile device downloads and stores the partial coded slices of the original data from the content server of the cellular network in advance, and The part of code fragments downloaded by the second smart mobile device is different from the part of code fragments downloaded by the first smart mobile device;

The decoding module is configured to perform random linear decoding on all coded slices of the original data obtained by the first smart mobile device to recover the original data.

Further, the above-mentioned data downloading system can also have the following characteristics, assuming that the total number of original data fragments of the original data is M, m is the number of original data fragments downloaded by the first smart mobile device, and T is the preset total download delay, T' is the remaining download time, and the download module includes:

The first judging unit is used to judge whether the actual download progress is less than the expected download progress, the actual download progress is equal to the ratio m/M of m to M, and the expected actual download progress is equal to the ratio T'/T of T' to T;

A processing unit, configured to download a coded fragment of the original data from a content server of the cellular network when the judgment result of the first judging unit is that the actual download progress is less than the expected download progress, otherwise no longer download from the content server of the cellular network The server downloads the encoded fragments of the original data.

Further, the above-mentioned data downloading system may also have the following characteristics, and the acquisition module includes:

A switching unit, configured to receive the coded fragments of the original data sent by the second smart mobile device when the first smart mobile device and the second smart mobile device are within the short-distance communication range, and send The second smart mobile device sends its own coded slices of the original data, and the number of coded slices received by the first smart mobile device is equal to the number of sent coded slices;

The second judging unit is used to judge whether the code segment received by the first smart mobile device and sent by the second smart mobile device is linearly independent from the code segment already possessed by the first smart mobile device, and if so, continue Perform code fragment exchange with the second smart mobile device, or stop code fragment exchange with the second smart mobile device.

Furthermore, the above data downloading system may also have the following feature, the data volume of the original data fragments is smaller than the preset fragmentation volume threshold.

Further, the above data downloading system may also have the following features, the short distance communication is Bluetooth communication or WiFi communication.

The data download method and system of the present invention enable smart mobile devices to download part of the data through the cellular network first, and then share the downloaded data with each other through an opportunistic network data distribution mechanism based on random linear coding, and finally make each smart mobile device have a complete Data, on the premise of meeting the content download delay, reduces the cellular network traffic usage of all smart mobile devices, thereby reducing the cellular network data traffic.

Description of drawings

Figure 1(a) is a schematic diagram of a traditional cellular network data download method;

Figure 1(b) is a schematic diagram of collaborative data downloading based on opportunistic networks;

Fig. 2 is the flowchart of the data downloading method in the embodiment of the present invention;

Fig. 3 is a schematic diagram of a network applying the data downloading method of the present invention;

Fig. 4 is a structural block diagram of a data downloading system in an embodiment of the present invention.

detailed description

The principles and features of the present invention are described below in conjunction with the accompanying drawings, and the examples given are only used to explain the present invention, and are not intended to limit the scope of the present invention.

The application scenario of the present invention is that all devices in a collection of smart mobile devices need to download the same content with a large amount of data from a content server on the Internet (Internet), such as downloading software updates and video clips.

Fig. 2 is a flowchart of a data downloading method in an embodiment of the present invention. As shown in Figure 2, in this embodiment, the flow of the data download method may include the following steps:

Step S201, the content server of the cellular network divides the original data to be downloaded into multiple original data fragments, performs random linear coding on each original data fragment, and obtains multiple coded fragments, wherein each coded fragment contains all Partial information of original data fragmentation;

Smart mobile devices are usually carried by people, and the encounter duration of people is short and the data volume of the downloaded content is large, so the original content (that is, the original data to be downloaded, the same below) is divided into multiple small The data shards can make it possible to transmit at least one data shard in most of the encounter time.

In order to ensure that at least one data fragment can be transmitted within the meeting time, a fragmentation threshold can be set according to the specific application situation. When fragmenting, the data volume of the original data fragment is smaller than the preset fragmentation threshold.

In order to prevent different smart mobile devices from downloading the same segment, the segments downloaded by the smart mobile device through the cellular network need to be processed by random linear coding first. Assuming that the original content is divided into M pieces [b ₁ ,b ₂ ,…,b _M ], the coded pieces can be obtained by the following formula (1):

$c_i=\underset{j=1}{\overset{m}{\mathrm{\Σ}}}{\mathrm{\β}}_{i,j}\×b_j$ Formula 1)

In formula (1), the encoding coefficients β _i,1 , β _i,2 ,..., β _i,M are randomly selected from the Gaussian field (GaloisField, GF), and the operators are all performed in the corresponding Gaussian field operation. After random linear encoding, each encoded slice will contain partial information of all original data slices. Any M linearly independent encoding slices can recover the original M slices.

Step S202, the first smart mobile device to download the original data downloads part of the encoded fragments of the original data from the content server of the cellular network;

Wherein, the first smart mobile device and the second smart mobile device mentioned below may be mobile phones. Smart mobile devices have long-distance cellular network communication interfaces and short-distance WiFi and Bluetooth communication interfaces, so they can communicate with all devices on the Internet through cellular networks, and can also communicate with nearby smart mobile devices through WiFi and Bluetooth (Bluetooth). Device communication.

Step S203, the first smart mobile device obtains the remaining coded slices of the original data from at least one second smart mobile device that describes the coded slices of the original data through short-distance communication, and the remaining coded slices are the same as those downloaded in step S202. Partially coded slices constitute all coded slices of the original data, and the second smart mobile device downloads and stores the partial coded slices of the original data from the content server of the cellular network in advance, and the partial coded slices downloaded by the second smart mobile device are different Part of the code segment downloaded on the first smart mobile device;

Wherein, the short distance communication may be Bluetooth communication or WiFi communication.

What needs to be explained here is that both the first smart mobile device and the second smart mobile device are smart mobile devices that need to download original data from the content server of the cellular network. fragments, but each smart mobile device downloads part of the coded fragments of the original data from the content server of the cellular network, which may be the same or different. way to obtain all encoded slices of the original data. Here, the purpose of distinguishing the first smart mobile device from the second smart mobile device is only to illustrate that the two are not the same smart mobile device, and that the partial code segments downloaded by the two are different.

In step S204, the first smart mobile device performs random linear decoding on all coded slices of the obtained original data to restore the original data.

In the embodiment of the present invention, step S202 may include the following sub-steps, and herein, this specific download strategy is referred to as an adaptive download strategy:

Suppose the total number of raw data fragments of raw data is M, m is the number of raw data fragments downloaded by the first smart mobile device, T is a preset total download delay, and T' is the remaining download time;

Judging whether the actual download progress is less than the expected download progress, the actual download progress is equal to the ratio m/M of m and M, and the expected actual download progress is equal to the ratio T'/T of T' to T;

If it is smaller, then download a coded segment of the original data from the content server of the cellular network, otherwise no longer download the coded segment of the original data from the content server of the cellular network.

In the embodiment of the present invention, step S203 may include the following sub-steps:

When the first smart mobile device and the second smart mobile device are within the short-distance communication range, it receives the encoded fragments of the original data sent by the second smart mobile device, and sends the second smart mobile device its own The coded slices of the original data, the number of coded slices received by the first smart mobile device is equal to the number of coded slices sent;

The first smart mobile device judges whether the received coded slices sent by the second smart mobile device are linearly independent from the coded slices it already has, if so, continue to exchange coded slices with the second smart mobile device, otherwise stop communicating with the second smart mobile device The second smart mobile device performs coded fragment exchange.

This specific embodiment adopts the idea of "barter" based on random linear coded opportunistic network data distribution mechanism to solve the fairness problem and motivate smart mobile devices to download partial fragments through the cellular network. When two smart mobile devices meet, they exchange a re-encoded segment with each other via WiFi or Bluetooth. Assume that the existing coded slices (including recoded slices) of a certain device are [c ₁ ,c ₂ ,…,c _k ], and the recoded slices are obtained by the following formula (2):

$c=\underset{j=1}{\overset{k}{\mathrm{\Σ}}}{\mathrm{\β}}_j\×c_j$ Formula (2)

In formula (2), the encoding coefficients β ₁ , β ₂ , ..., β _k are randomly selected from the Gaussian domain, and the operators are all operated in the corresponding Gaussian domain. There is no essential difference between re-encoded slices and encoded slices, and no distinction is made during transmission. After the smart mobile device receives the coded slice sent by the neighbor device, it can use the Gaussian elimination method to check the linear independence. If the newly received coded slice is nonlinearly independent from the coded slice it has stored, it will stop encoding with the neighbor. Shard exchanges; if linearly independent, proceed to encode shard exchanges.

The present invention will be further described in detail through a specific application example below.

Fig. 3 is a schematic diagram of a network applying the data downloading method of the present invention. In this embodiment, the content server adopts a common Internet server, and the smart mobile device adopts an operating system above Android 2.0 and a smart phone with a Bluetooth communication function. The mobile phone memory is above 218MB, and the external memory is above 4GB. When new content is generated, on the one hand, the content server divides the original content into fragments with a size of 500KB, and uses a random linear coding algorithm to encode these original fragments into a certain number of coded fragments; on the other hand, the content server sends a message To all smart mobile devices that have subscribed to the content, notify the smart mobile devices to start downloading the content.

After receiving the download notification, on the one hand, the smart mobile device continuously downloads coded fragments through the cellular network according to the above-mentioned adaptive download strategy; If you also subscribe to the content, then according to the above-mentioned opportunistic network data distribution mechanism based on random linear coding, the "barter exchange" of coded fragments will be carried out. The above two processes continue until the mobile device has enough coded fragments, that is, enough coded fragments to be able to recover the complete original content.

In the data downloading method of the present invention, the smart mobile device first downloads part of the data through the cellular network, and then shares the downloaded data with each other through an opportunistic network data distribution mechanism based on random linear coding, so that each smart mobile device has complete data at last. Under the premise of meeting the content download delay, the cellular network traffic usage of all smart mobile devices is reduced, thereby reducing the data traffic of the cellular network.

The present invention also proposes a data downloading system for executing the above data downloading method.

Fig. 4 is a structural block diagram of a data downloading system in an embodiment of the present invention. As shown in FIG. 4 , in this embodiment, the data downloading system may include a fragmentation and encoding module 410 , a downloading module 420 , an obtaining module 430 and a decoding module 440 . The fragmentation and encoding module 410, the downloading module 420, the obtaining module 430 and the decoding module 440 are connected in sequence. Wherein, the fragmentation and encoding module 410 is used to divide the original data to be downloaded into multiple original data fragments, perform random linear coding on each original data fragment, obtain multiple coded fragments, and store them on the content server of the cellular network , where each coded slice contains partial information of all original data slices. The downloading module 420 is used for downloading part of coded slices of the original data from the content server of the cellular network, and storing them on the first smart mobile device to download the original data. The acquiring module 430 is configured to enable the first smart mobile device to acquire the raw data from at least one second smart mobile device having coded slices of the raw data through short-distance communication (the short-distance communication may be Bluetooth communication or WiFi communication). The remaining coded slices, the remaining coded slices and the partial coded slices downloaded by the download module 420 constitute all the coded slices of the original data, the second smart mobile device downloads the partial coded slices of the original data from the content server of the cellular network in advance and stored, and the part of the code segment downloaded by the second smart mobile device is different from the part of the code segment downloaded by the first smart mobile device. The decoding module 440 is configured to perform random linear decoding on all coded slices of the original data obtained by the first smart mobile device to restore the original data.

In the embodiment of the present invention, the download module 420 may further include a first judging unit and a processing unit. The first judging unit is used to judge whether the actual download progress is less than the expected download progress, wherein the actual download progress is equal to the ratio m/M of m and M, and the expected actual download progress is equal to the ratio T′/T of T′ and T, and M is the original The total number of original data segments of the data, m is the number of original data segments downloaded by the first smart mobile device, T is the preset total download delay, and T' is the remaining download time. The processing unit is used to download an encoded segment of the original data from the content server of the cellular network when the judgment result of the first judging unit is that the actual download progress is less than the expected download progress, otherwise no more downloading of the original data from the content server of the cellular network Encode slices.

In the embodiment of the present invention, the acquiring module 430 may further include a switching unit and a second judging unit. Wherein, the switching unit is configured to receive the encoded fragments of the original data sent by the second smart mobile device when the first smart mobile device and the second smart mobile device are within the short-distance communication range, and send the coded fragments to the second smart mobile device. The mobile device sends its own encoded fragments of the original data, and the number of encoded fragments received by the first smart mobile device is equal to the number of transmitted encoded fragments. The second judging unit is used for judging whether the encoded slice received by the first intelligent mobile device and sent by the second intelligent mobile device is linearly independent from the encoded slice already possessed by the first intelligent mobile device, and if so, continues to communicate with the second intelligent mobile device Code segment exchange, otherwise stop the code segment exchange with the second smart mobile device.

In the embodiment of the present invention, a fragmentation threshold can be set, and the data volume of the original data fragmentation is smaller than the preset fragmentation threshold.

The data downloading system of the present invention, by executing the above-mentioned data downloading method, enables the smart mobile device to download part of the data through the cellular network first, and then share the downloaded data with each other through the opportunistic network data distribution mechanism based on random linear coding, and finally makes each All smart mobile devices have complete data. On the premise of meeting the content download delay, the cellular network traffic usage of all smart mobile devices is reduced, thereby reducing the data traffic of the cellular network.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (8)

1. a data download method, for from Cellular Networks downloading data, is characterized in that, comprising:

Step a, the initial data that the content server of Cellular Networks will be downloaded is divided into multiple initial data burst, carry out stochastic linear coding to each described initial data burst, obtain multiple coded slices, each coded slices comprises the partial information of all initial data bursts;

Step b, the first Intelligent mobile equipment downloading described initial data downloads the code segment burst of described initial data from the content server of Cellular Networks; Step b comprises:

If total number of the initial data burst of described initial data is M, m is the initial data burst number that described first Intelligent mobile equipment has been downloaded, T is that default total download postpones, and T ' is residue download time;

Judge whether actual download progress is less than expectation download progress, described actual download progress equals the ratio m/M of m and M, and described expectation download progress equals the ratio T '/T of T ' and T;

If be less than, then download the coded slices of a described initial data from the content server of Cellular Networks, otherwise no longer download the coded slices of described initial data from the content server of Cellular Networks;

Step c, described first Intelligent mobile equipment passes through short-range communication, the residue coded slices of described initial data is obtained from least one second Intelligent mobile equipment of the coded slices with described initial data, described residue coded slices and described code segment burst form whole coded slices of described initial data, described second Intelligent mobile equipment is downloaded the code segment burst of described initial data from the content server of Cellular Networks in advance and is stored, and the code segment burst that described second Intelligent mobile equipment is downloaded is different from the code segment burst that described first Intelligent mobile equipment is downloaded,

Steps d, the whole coded slices of described first Intelligent mobile equipment to the described initial data obtained carry out stochastic linear decoding, recover described initial data.

2. data download method according to claim 1, is characterized in that, step c comprises:

When described first Intelligent mobile equipment and described second Intelligent mobile equipment are near field communication range, receive the coded slices of the described initial data that described second Intelligent mobile equipment sends, and the coded slices of the described initial data oneself had is sent to described second Intelligent mobile equipment, the coded slices that described first Intelligent mobile equipment receives is equal with the coded slices quantity of transmission;

Described first Intelligent mobile equipment judges the coded slices the Line independent whether coded slices that described second Intelligent mobile equipment received sends has had with oneself, if then continue to carry out coded slices exchange with described second Intelligent mobile equipment, otherwise stop carrying out coded slices exchange with described second Intelligent mobile equipment.

3. data download method according to claim 1, is characterized in that, the data volume of described initial data burst is less than default burst amount threshold value.

4. data download method according to claim 1, is characterized in that, in step c, described short-range communication is Bluetooth communication or WiFi communication.

5. a data downloading system, for from Cellular Networks downloading data, is characterized in that, comprising:

Burst and coding module, initial data for downloading is divided into multiple initial data burst, stochastic linear coding is carried out to each described initial data burst, obtain multiple coded slices, deposit on the content server of Cellular Networks, each coded slices comprises the partial information of all initial data bursts;

Download module, for downloading the code segment burst of described initial data from the content server of Cellular Networks, deposits in and will download on the first Intelligent mobile equipment of described initial data; If total number of the initial data burst of described initial data is M, m is the initial data burst number that described first Intelligent mobile equipment has been downloaded, T is that default total download postpones, and T ' is residue download time, and described download module comprises:

First judging unit, for judging whether actual download progress is less than expectation download progress, described actual download progress equals the ratio m/M of m and M, and described expectation download progress equals the ratio T '/T of T ' and T;

Processing unit, for in the judged result of described first judging unit be actual download progress be less than expect download progress time, download the coded slices of a described initial data from the content server of Cellular Networks, otherwise no longer download the coded slices of described initial data from the content server of Cellular Networks;

Acquisition module, short-range communication is passed through for making described first Intelligent mobile equipment, the residue coded slices of described initial data is obtained from least one second Intelligent mobile equipment of the coded slices with described initial data, described residue coded slices and described code segment burst form whole coded slices of described initial data, described second Intelligent mobile equipment is downloaded the code segment burst of described initial data from the content server of Cellular Networks in advance and is stored, and the code segment burst that described second Intelligent mobile equipment is downloaded is different from the code segment burst that described first Intelligent mobile equipment is downloaded,

Decoder module, the whole coded slices for the described initial data obtained described first Intelligent mobile equipment carry out stochastic linear decoding, recover described initial data.

6. data downloading system according to claim 5, is characterized in that, described acquisition module comprises:

Crosspoint, for when described first Intelligent mobile equipment and described second Intelligent mobile equipment are near field communication range, receive the coded slices of the described initial data that described second Intelligent mobile equipment sends, and the coded slices of the described initial data oneself had is sent to described second Intelligent mobile equipment, the coded slices that described first Intelligent mobile equipment receives is equal with the coded slices quantity of transmission;

Second judging unit, for judging the coded slices the Line independent whether coded slices that described second Intelligent mobile equipment that described first Intelligent mobile equipment receives sends has had with described first Intelligent mobile equipment, if then continue to carry out coded slices exchange with described second Intelligent mobile equipment, otherwise stop carrying out coded slices exchange with described second Intelligent mobile equipment.

7. data downloading system according to claim 5, is characterized in that, the data volume of described initial data burst is less than default burst amount threshold value.

8. data downloading system according to claim 5, is characterized in that, described short-range communication is Bluetooth communication or WiFi communication.