WO2006075276A2

WO2006075276A2 - Piconetworking systems

Info

Publication number: WO2006075276A2
Application number: PCT/IB2006/050069
Authority: WO
Inventors: Jozef P. Van Gassel; Ozcan Mesut; Hendrikus B. Van Den Brink; Artur Burchard; Siarhei Yermalayeu; Steven B. Luitjens
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2005-01-12
Filing date: 2006-01-09
Publication date: 2006-07-20
Also published as: WO2006075276A3

Abstract

A method of transferring data between devices over a network is disclosed wherein a source device having desired data available for transfer is selected, from a plurality of such devices, to transfer such data in dependence upon the power characteristics of the source device concerned.

Description

Piconetworking systems

The present invention relates to networking systems, and in particular but not exclusively, to wireless networks.

A wireless in-home network typically connects various kinds of entertainment and productivity devices with each other and enables them to share content with one another. Home media center, TV, personal audio-video jukebox, touch screen remote control, personal computer (PC), notebook, personal digital assistant (PDA) are all examples of such devices. The personal audio-video jukebox synchronizes (automatically) with the home media center wirelessly or wired in its cradle while recharging its battery. The PDA synchronizes the same way with the PC. All devices and their services can be visible on a display of a control device. One preferred control device is a remote control device which uses a touch screen. Using the control device, the user can start content exchange between devices or stream content from media servers (media center, personal jukebox PC) to media Tenderers (TV, personal jukebox, remote control, audio set).

However, existing networks of this type have the disadvantage that when a user chooses content, e.g. audio or video, to be streamed/transferred from a battery powered mobile server to a media renderer, the battery of the mobile server may be drained, and the transfer might stop abruptly if the battery runs empty. Another disadvantage of existing networks is that when media content is streamed from a battery powered mobile server to a media renderer, battery power can be wasted if the bandwidth of the battery powered device is not fully utilized. This under utilization can be caused, for example, if the receiving device does not have the required bandwidth capability, does not have enough storage capability to buffer the incoming media content stream, and/or has a slow wireless connection.

Accordingly, it is desirable to provide networking techniques which avoid such disadvantages. According to one aspect of the present invention, there is provided a method of transferring data between devices over a network wherein a source device having desired data available for transfer is selected, from a plurality of such devices, to transfer such data in dependence upon the power characteristics of the source device concerned. According to another aspect of the present invention, there is provided an access control device for controlling data transfer between devices, interconnected by a computer network, the access control device being operable to control transfer of data items between devices by selecting a source device having desired data available for transfer, from a plurality of such devices, in dependence upon the power characteristics of the source device concerned.

In one particular embodiment of the present invention, the selection of the source device is made upon receipt of a data transfer request, whilst in another embodiment a preferred source device for each available data item is selected in advance of receipt of a transfer request. The selected device can be selected as follows: the device is mains powered

(i.e. receives its power from a mains electricity supply), the device has the highest available power of the device in the said group, the device has the lowest power per data bit transferred ratio of the devices in the said group, or the device has sufficient available power to complete the requested transfer of the desired data items. Alternatively, if none of the devices in the group of devices has enough power to complete the transfer of the desired data items, then the transfer commences with a first device of the group, and continues with further devices of the group as power is depleted in the first and further devices.

According to a further aspect of the present invention, there is provided a method and control device for transferring data between devices over a network, wherein a receiving device for desired data items is selected in dependence upon the available data reception rate of the device concerned.

Brief description of the drawings:

Fig. 1 illustrates an example network according to the present invention; Fig. 2 illustrates a device for use in the networked Fig. 1; and Fig. 3 illustrates steps in a method embodying the present invention. Fig. 4 illustrates an alternative method embodying the present invention. Figure 1 illustrates a network 1 embodying the present invention. The network 1 comprises network areas 10, 20, 30, which correspond to rooms 1, 2 and 3 respectively. The example network shown in Figure 1 is of a home network in which various rooms contain various network devices. In addition to the three fixed network areas 10, 20 and 30, a mobile server 40 is provided.

Network area 10 (room 1) comprises, in the example shown in Figure 1, a media server 12 and a media renderer 14. The second area 20 includes a media server 22, and the area 30 comprises a media renderer 34. A media server (MS) stores data relating to individual media files and supplies these files to the media renderer. The media renderer converts the received files into media output for the user. For example, a television is a media renderer that converts media data files into video and audio signals for output on a display device and loudspeakers respectively.

Each of the servers 12, 22 and 40, and Tenderers 14, 34 and 40 are able to communicate with one another using network infrastructure, which is not shown in Figure 1 for the sake of clarity. The network can include fixed or wireless networking devices, or a combination of the two. Each of the devices shown in Figure 1, which utilize the present invention, preferably use UPnP protocols for the control of transfer of media content.

Figure 2 illustrates an access control device which is used in embodiments of the present invention. The access control device 50 includes a network interface 54 which operates to transfer data to and from the network. A controller 52 serves to control access to the network, communicates with a user via a user interface 56, and is operable to store and retrieve information from a storage device 58. The access control device 50 can be provided by any one or more of the network devices, or by a separate control device connected to the network. In particular, this functionality could be part of the stationary Media Center, the mobile device (with a built-in control point) or a third separate physical control point.

Operation of the network 1 of Figure 1 and the access control device of Figure 2 will now be described with reference to the flow chart of Figure 3. In the example of Figure 3, a user is described as using the mobile server 40 of Figure 1. However, it will be readily appreciated that any device can operate according to the method described below.

At step A, a user of the mobile server 40 selects a media content item that they wish to download to the mobile server from a media server or media renderer in the other parts of the network. This downloading can be real time streaming or could be a "best-effort" (i.e. as fast as possible) data transfer. At step B, the access control device 50 determines whether the media server is "power aware". A "power aware" device is one that stores power information regarding the status of its power source and power consumption properties. For example, the device may be mains powered, or battery powered. If the device is battery powered, then the stored power information will preferably include details of the state of charge of the battery, its expected remaining lifetime etc. The access control device must determine whether the requested source of the requested data (i.e. the content) has the required power to enable delivery of the data items to the mobile server 40 to be completed. If the source device is power aware, then the access control device determines possible alternate sources for the data (step C). To locate alternative sources of the requested media content for requested data stream, the access control device 50 searches other servers and Tenderers on the network for the data stream concerned. This search can take place in any suitable manner. For example, in UPnP, the Content Directory Service (CDS) can be used to find appropriate content. Alternatively, or additionally, a search algorithm can be used to search the server container (i.e. directory) and item (i.e. file) structure. In one implementation of the present invention the control points queries the stationary Media Server(s) using the Content Directory Service (CDS) to find (alternative locations) for the desired content in the fixed network. Items in the CDS can have multiple references to physical representations of the same content (possibly in different locations) or can be stored in different objects. Detecting different versions of the same identical content can be achieved using standard technologies like for instance CRC or MD5SUM hashes.

The exact location of the content needs to be resolved by examining the URL of the stored objects. This URL needs to be checked against the list of known devices of the control point (which can be acquired using the UPnP discovery mechanism), which then subsequently results in the UDN (unique device number). By using a special service or vendor specific actions, special properties of the servers can be collected from a particular server with the given UDN. By comparing the properties of different Media Servers offering the same content, the control point or media server can select the most optimum Media Server based on the above-mentioned criteria. Subsequently the actual streaming will take place from the most optimum Media Server to the Media Renderer. The control device resolves the unique device number (UDN) from the host name (step D), and then queries the power properties of the alternate sources for the requested data stream. One of the available sources of the requested data stream is selected on the basis of power property criteria (step F), and then a connection is set up between the requesting device media renderer and the selected source device (MS), as illustrated in step G. At step H, the media renderer can start playback of the content.

As an alternative, a Media Server could compile the optimum source information in advance of receiving a particular request. In that case, the Media Server would then only supply information to a requesting device about the optimum source, and would not have to compile the information in real time. Figure 4 illustrates this alternative method. At step I, the Media Server searches for data source devices, and resolves the UDNs from the hostnames at step ii. The power characteristics of each such device are then queried (step iii), and an optimum data source device is selected for each data item (step v). When a request for data is received (step vi), data transfer between the optimum source device and the receiving device is initiated (step vii).

Selection of the source for the requested data is made by consideration of power characteristics of the potential source devices. Various different criteria can be used to identify the most appropriate source device for the requested data stream and the following are given as examples only. A mains electricity connected device is considered to have limitless power available, and so is always the preferred source device. Where only battery powered sources are available, other characteristics are taken into account. For example, the overall available power levels of the battery-powered devices can be compared and the highest available power battery selected. Alternatively, the device with the lowest power requirement per bit of data transferred can be selected. A further alternative is to select the battery powered device which is able to complete the data transfer. These different criteria can be balanced against one another, for example if the potential choice of source device is not clear.

The devices in the network 1 or, at least the control-points thereof, must know, depending upon the criterion used for device selection:

1. Which devices are battery-powered and which ones are not.

2. The energy consumption per transferred bit of each device.

3. The data transfer rate of each device.

4. The remaining battery energy of each mobile device. Internet Protocol (IP)-based networks typically use the UPnP for streaming between a server device and a renderer device. This is standardized in the UPnP A/V Architecture using Connection Manager and AV Transport services. In order to make the correct source selection decision, a provision must be added to UPnP that allows control points in the network to query characteristics of the devices and the connections it needs to establish. In embodiments of the present invention, actions (or services) are added to UPnP that are used to query battery status, energy per bit, data transfer rates, power type (battery or mains) etc.

The present invention can be applied to all battery powered devices with storage and wireless connectivity and to home media servers/access points that can connect to the mentioned mobile devices wirelessly. The present invention is particularly suited to audio/visual (AV) data, but it will be readily appreciated that the principles are applicable to any data transfer.

Implementing the first aspect of the present invention enables power optimized data transfer to be performed in wired/wireless networks. It is particularly relevant to have networking and other networks that provide streaming media data to and from battery powered devices.

In a second aspect of the present invention, the bandwidth of the receiving device is compared to the transmitting bandwidth available to the battery-powered device. If the receiver's available receiving bandwidth is less than that available to the battery-powered device for transmission of a data stream, then it is desirable to choose an alternative receiving device. The alternative receiving device is chosen in order to allow the battery-powered device to transfer the media content at full speed (i.e. to use fully its available transmitting bandwidth), and then enter a low power mode, such that battery power can be saved. It is preferable to choose a mains electricity powered device as the alternative device, in order to avoid a knock-on effect of using battery power in other devices. The alternative receiving device can then transfer the received data to the original target receiving device. As the alternative device is preferably mains powered, the lower transfer rate allowed by the originally chosen receiving device is less of an issue. This is because the alternative receiving device does not have the same power consumption issues as the transmitting device.

In order to implement this aspect of the present invention, the devices attached to the network must be able to detect whether another device is battery powered, and the available data transfer rate of each of the devices.

Claims

CLAIMS:

1. A method of transferring data between devices over a network wherein a source device having desired data available for transfer is selected, from a plurality of such devices, to transfer such data in dependence upon the power characteristics of the source device concerned.

2. A method as claimed in claim 1, comprising the steps of: receiving, from a requesting device, a data transfer request for desired data items to be transferred to a sink device; determining a group of at least one device, the or each device in the group having the desired data items available for transfer; selecting a source device from the said group for transfer of the desired data items in dependence upon the power characteristics of the source device; and transferring the desired data items from the selected source device to the sink device over the network.

3. A method as claimed in claim 1, comprising the steps of: for available data items, determining a group of at least one device, the or each device in the group having said data items available for transfer; selecting a source device for each data item from the said group in dependence upon the power characteristics of the source device; and receiving, from a requesting device, a data transfer request for desired data items to be transferred to a sink device; transferring the desired data items from the selected source device for those data items to the sink device over the network.

4. A method as claimed in claim 2 or 3, wherein the selected device is mains powered.

5. A method as claimed in claim 2 or 3, wherein the selected device has the highest available power of the device in the said group.

6. A method as claimed in claim 2 or 3, wherein the selected device has the lowest power per data bit transferred ratio of the devices in the said group.

7. A method as claimed in claim 2 or 3, wherein the selected device has sufficient available power to complete the requested transfer of the desired data items.

8. A method as claimed in claim 12 or 3, wherein, if none of the devices in the group of devices has enough power to complete the transfer of the desired data items, then the transfer commences with a first device of the group, and continues with further devices of the group as power is depleted in the first and further devices.

9. A method as claimed in claim 2 or 3, wherein the determining step comprises: determining devices which are mains powered, and which have the desired data items available for transfer; and if no such devices are determined, determining battery powered devices which have the desired data items available for transfer.

10. An access control device for controlling data transfer between devices (12, 14, 22, 34, 40), interconnected by a computer network (1), the access control device (50) being operable to control transfer of data items between devices (12, 14, 22, 34, 40) by selecting a source device having desired data available for transfer, from a plurality of such devices, in dependence upon the power characteristics of the source device concerned.

11. An access control device as claimed in claim 10, comprising: a controller (52) operable to receive a data transfer request from a requesting device of a plurality of devices, the data transfer request relating to transfer of desired data items to a sink device of the plurality of devices, to determine a group of at least one device from the plurality of devices, the or each device in the group having the desired data items available for transfer, to select a source device from the group of devices for transfer of the desired data items in dependence upon the power characteristics of the source device, and to initiate transfer of the desired data items from the selected source device to the sink device over the network (1).

12. An access control device as claimed in claim 10, comprising: a controller (52) operable, for each available data item, to determine a group of at least one device, the or each device in the group having said data item available for transfer, to select a corresponding source device from the said group of devices for each data item in dependence upon the power characteristics of the corresponding source device; and to initiate transfer of a desired data item from the corresponding selected source device to a sink device in response to receipt of a data transfer request relating to the desired data item.

13. A method transferring data between devices over a network, wherein a sink device for receiving desired data items is selected in dependence upon the available data reception rate of the device concerned.

14. A method as claimed in claim 13, comprising the steps of: - receiving, from a requesting device, a data transfer request for desired data items to be transferred to a sink device, the desired data items being available on a source device; determining a first data transfer rate relating to a rate at which the sink device is able to receive data; - determining a second data transfer rate relating to a rate at which the source device is able to transmit data; comparing the first and second data transfer rates; and if the first data transfer rate is less then the second transfer rate:

- searching for an alternative device, which alternative device has a third data transfer rate relating to a rate at which the alternative device is able to receive data, the third data transfer rate being greater than or equal to the first transfer rate;

- transferring the requested data items from the source device to the intermediate device; and

- transferring the requested data items to the requesting device from the intermediate device; or if the first data transfer rate is greater than or equal to the second data transfer rate:

- transferring the requested data items directly from the source device to the requesting device.

15. An access control device for controlling data transfer between devices (12, 14, 22, 34, 40) interconnected by a network (1), the access control device being operable to select a sink device for receiving desired data items in dependence upon the available data reception rate of the sink device concerned.

16. An access control device as claimed in claim 15, comprising: a controller (52) operable to receive, from a requesting device, a data transfer request for desired data items to be transferred to a sink device, the desired data items being available on a source device, to determine a first data transfer rate relating to a rate at which the sink device is able to receive data, to determine a second data transfer rate relating to a rate at which the source device is able to transmit data, to compare the first and second data transfer rates, and if the first data transfer rate is less then the second transfer rate, to search for an alternative device, which alternative device has a third data transfer rate relating to a rate at which the alternative device is able to receive data, the third data transfer rate being greater than or equal to the first transfer rate, to initiate transfer of the requested data items from the source device to the intermediate device, and from the intermediate device to the requesting device, or, if the first data transfer rate is greater than or equal to the second data transfer rate, to initiate transfer of the requested data items directly from the source device to the requesting device.