GB2454648A

GB2454648A - Content item distribution using broadcast and point-to-point communication means

Info

Publication number: GB2454648A
Application number: GB0720493A
Authority: GB
Inventors: Simon Waddington; Craig Watson; Sandra C Gadanho
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 2007-10-19
Filing date: 2007-10-19
Publication date: 2009-05-20
Also published as: GB0720493D0

Abstract

A content item distribution system uses a broadcast communication system and a point-to-point communication system to distribute content items. A content recommender (303) generates a set of recommendations of content items for each user and a content set processor (307) combines the recommendations into a combined set. A cost processor (309) generates a communication cost measure for each content item of the combined set which includes a first cost measure for the broadcast communication system and a second cost measure for the point-to-point communication system. A communication processor (311) selects a subset of content items for distribution using the broadcast communication system by minimising a combined cost measure being a combination of cost measures for the content items of the combined set. The cost measure for a content item is selected as the first or second cost measure depending on which communication system is selected for the content item.

Description

CONTENT ITEM DISTRIBUTION

Field of the invention

The invention relates to content item distribution and in particular to content item distribution using broadcast and point-to- point communication means.

Background of the Invention

In recent years, the availability and provision of multimedia and entertainment content has increased substantially. E.g., the number of available television and radio channels has grown considerably and the popularity of the Internet has provided new content distribution means.

Consequently, users are increasingly provided with a plethora of different types of content from different sources. In order to identify and select the desired content, the user must typically process large amounts of information which can be very cumbersome and impractical.

In order to facilitate and improve the user experience, personalization has been introduced where content for a user is selected in accordance with the user's specific preferences and characteristics. For example centralised servers have been developed which execute a reasoning algorithm to generate recommendations of specific content items for individual users. The recommended content items can then be transmitted to the users.

For example, personalized multimedia content may be distributed to users of mobile and fixed consumer terminals over a suitable communication system. A content push system is any system where the delivery of content from the content source to the user can be initiated whenever the user terminal is connected to the system. An example of such content distribution systems would be mobile video or TV services, RSS newsreaders or widgets.

Content that can be recommended includes e.g. news and information content, advertisements for products and services, television programmes etc. The individual content items can e.g. be text based documents, video clips or audio clips.

Content distribution may be achieved using a point-to-point communication system wherein the content item is communicated directly from one source (the distribution server) to one destination (the individual user device or terminal) . Alternatively, content distribution may be achieved using broadcasting means wherein a content item is broadcasted to a plurality of destinations (i.e. using point to multipoint communication) A content push application based on point-to-point delivery can for example deliver and cache content items on mobile phone handsets. The content items can be delivered as a background application and can allow a user to select a content item to read a piece of text, start a video or audio clip from cache, or connect to an external server etc. The content items can e.g. be delivered using a dedicated point-to-point communication channel of a cellular mobile communication system.

However, the use of point-to-point networks for delivering the same content items to many users is inefficient and results in a high resource usage. However, it does offer the potential to provide individually personalized content and advertisements to individual users thereby providing an improved user experience.

An alternative approach to delivering push content is via broadcast communication means. For example, content items may be broadcast using cell broadcast techniques of a cellular communication system. Such an approach is far more efficient for delivering non-personalized content or content which is common to a large group of users. However, the approach is less suitable for personalized content as broadcast resources tend to be limited and are inefficient for communication to only a single user or a small group of users.

Thus, current personalized content item distribution has a number of associated disadvantages and an improved distribution system would be advantageous. In particular content item distribution allowing increased flexibility, more efficient resource usage, improved adaptation to current communication conditions and/or improved performance

Summary of the Invention

Accordingly, the Invention seeks to preferably mitigate, alleviate or eliminate one or more of the above mentioned disadvantages singly or in any combination.

According to a first aspect of the invention, there is provided a content item distribution apparatus for distributing content items using a broadcast communication system or a point-to-point communication system, the apparatus comprising: a recommender generating a set of recommendations of content items for each user of a plurality of users; means for generating a combined set of recommended content items by combining the sets of recommendations; means for generating a communication cost measure for each content item of the combined set, the communication cost measure for a given content item comprising a first cost measure indicative of a resource cost associated with distributing the given content item using the broadcast communication system and a second cost measure indicative of a resource cost associated with distributing the given content item using the point-to-point communication system; allocation means for selecting a first subset of content items of the combined set for distribution using the broadcast communication system by minimising a combined cost measure being a combination of cost measures for the content items of the combined set, the cost measure for each content item being the first cost measure if the content item is selected to be included in the first subset and the second cost measure if the content item is selected not to be included in the first subset.

The invention provides improved content item distribution for personalized content. An improved utilisation of the relative advantages of point-to-point and broadcast communication systems for personalized content may be achieved. The usage of point-to-point and broadcast communication may in particular be selected to reflect the specific recommendations as well as the associated advantages and disadvantages of transmitting the individual recommended content items using point-to- point or broadcast communication channels.

For example, content items which the recommender has recommended to more than a given number of users may advantageously be transmitted over the broadcast communication system whereas content items which the recommender has recommended to less than the given number of users may advantageously be transmitted over the point-to-point communication system. The use of resource cost measures for communicating an individual content item over respectively the broadcast and the point-to-point communication system in a joint optimisation of the combined cost measure for all content items may provide particularly advantageous performance.

The system may achieve a more efficient resource usage of the available communication resource.

The broadcast communication system and the point-to-point communication system may be part of a single communication system such as a cellular communication system.

According to another aspect of the invention there is provided a content item distribution system comprising a broadcast communication system and a point-to-point communication system, the communication system comprising a content item distributor and a plurality of content item devices wherein the content item distributor comprises: a recommender generating a set of recommendations of content items for each user of a plurality of users, means for generating a combined set of recommended content items by combining the sets of recommendations, means for generating a communication cost measure for each content item of the combined set, the communication cost measure for a given content item comprising a first cost measure indicative of a resource cost associated with distributing the given content item using the broadcast communication system and a second cost measure indicative of a resource cost associated with distributing the given content item using the point-to-point communication system, allocation means for selecting a first subset of content items of the combined set for distribution using the broadcast communication system by minimising a combined cost measure being a combination of cost measures for the content items of the combined set, the cost measure for each content item being the first cost measure if the content item is selected to be included in the first subset and the second cost measure if the content item is selected not to be included in the first subset, means for broadcasting the first subset using the broadcast communication system, and means for transmitting via the point-to-point communication system at least a first of the content items not included in the first subset to a first content item device associated with a user for which the at least one content item has been recommended; and the first content item device comprises: means for receiving the first subset via the broadcast communication system, means for receiving the first content item via the point-to-point communication system, and means for generating a set of recommended content items comprising the first content items and at least one content item of the first subset.

According to another aspect of the invention there is provided a method of content item distribution for distributing content items using a broadcast communication system or a point-to-point communication system, the method comprising: generating a set of recommendations of content items for each user of a plurality of users; generating a combined set of recommended content items by combining the sets of recommendations; generating a communication cost measure for each content item of the combined set, the communication cost measure for a given content item comprising a first cost measure indicative of a resource cost associated with distributing the given content item using the broadcast communication system and a second cost measure indicative of a resource cost associated with distributing the given content item using the point-to-point communication system; and selecting a first subset of content items of the combined set for distribution using the broadcast communication system by minimising a combined cost measure being a combination of cost measures for the content items of the combined set, the cost measure for each content item being the first cost measure if the content item is selected to be included in the first subset and the second cost measure if the content item is selected not to be included in the first subset.

These and other aspects, features and advantages of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

Brief Description of the Drawings

Embodiments of the invention will be described, by way of example only, with reference to the drawings, in which FIG. 1 is an illustration of a content item distribution system in accordance with some embodiments of the invention; FIG. 2 is an illustration of different communication means of a content item distribution system in accordance with some embodiments of the invention; FIG. 3 is an illustration of a distribution server in accordance with some embodiments of the invention; FIG. 4 illustrates an example of a method of content item distribution in accordance with some embodiments of the invention; FIG. 5 is an illustration of a multimedia terminal in accordance with some embodiments of the invention; FIG. 6 illustrates an example of a method of content item distribution in accordance with some embodiments of the invention; and FIG. 7 illustrates an example of a method of content item distribution in accordance with some embodiments of the invention.

Detailed Description of Some Embodiments of the Invention The following description focuses on embodiments of the invention applicable to content distribution using a cellular communication system and in particular to content distribution using a Global System for Mobile (GSM) or a Universal Mobile Telecommunication System (UNTS) system.

However, it will be appreciated that the invention is not limited to this application but may be applied to many other content item distribution applications and communication systems.

FIG. 1 illustrates an example of a cellular communication system suitable for content item distribution in accordance with some embodiments of the invention.

The cellular communication system is a GSM/UMTS cellular communication system which supports a plurality of user equipments. In the example two user equipments in the form of multimedia terminals 101, 103 supported by a base station are shown but it will be appreciated that a typical cellular communication system will support a large number of user equipments of which only some may be able to receive and process distributed content items.

The base station 105 is coupled to a GSM/UMTS network 107 which represents all aspects of the fixed segment of the GSM/UMTS communication system including other base stations, Radio Network Controllers, Mobile Switching Centres etc as will be well known to the person skilled in the art.

The system of FIG. 1 furthermore comprises a distribution server 109 which is arranged to distribute content items to various user equipments and specifically to a group of multimedia terminals including the two illustrated multimedia terminals 101, 103. The multimedia terminals 101, 103 may for example be multimedia capable mobile phones. The multimedia content items provided from the distribution server 109 may e.g. comprise video and/or audio clips and/or text based documents or articles.

In the example, the two multimedia terminals 101, 103 are part of a group of multimedia terminals which are provided with multimedia content from the distribution server 109.

Thus, in some embodiments, the distribution server 109 may support a specific group of user equipments which e.g. subscribe to the content item provision service provided by the distribution server 109.

The distribution server 109 is coupled to the network 107 and is capable of sending the content items to the multimedia terminals 101, 103 supported by the distribution server 109.

In the example, the cellular communication system supports both broadcast communication services (point-to-multipoint) and dedicated point-to-point communication services and the distribution server 109 is capable of using both broadcast and point-to-point communication services when transmitting the content items to the multimedia terminals 101, 103.

Thus, a broadcast transmission of content items may be made allowing the same transmission to be received by a plurality of the multimedia terminals 101, 103. Alternatively, a point-to-point transmission of a content item may be made directly to one of the multimedia terminals 101, 103. Such a point-to-point communication cannot be received by any other of the multimedia terminals 101, 103. Thus if point-to-point communication is used for a content item for a plurality of multimedia terminals 101, 103, the content item must be individually transmitted to each of the multimedia terminals 101, 103.

FIG. 2 illustrates an example of the communication channels that can be used to distribute content items from the distribution server 109 to the multimedia terminals 101, 103. Specifically, the cellular communication system provides for individual point-to-point communication via a point-to-point network that establishes individual communication links 201, 203 between the distribution server 109 and the multimedia terminals 101, 103.

In addition, the cellular communication system provides a common broadcast communication link 205 for a plurality of multimedia terminals 101, 103. Thus, each multimedia terminal 101, 103 can connect to the distribution server 109 both via a point-to-point communication system and a broadcast system. In the example, the broadcast communication network/system can be formed by UMTS GPRS broadcast services or cell broadcast services and the point-to-point communication network/system can be formed by the conventional two party UMTS data communication services.

In the described embodiment, the cellular communication system thus effectively comprises both a broadcast communication system and a point-to-point communication system. Thus, the broadcast communication system and the point-to-point communication system may simply correspond to different communication services of a multi-service single communication system.

It will be appreciated that in other embodiments, the broadcast communication system and point-to-point communication system may be separate systems and may specifically he completely independent systems e.g. following different technical standards and/or being operated and managed independently. For example, the point-to-point communication may use a UMTS cellular communication system and the broadcast communication may use an independent DVB-H (Digital Video Broadcasting -Handheld) communication system. Other relevant broadcast standards would include S-DMB (Satellite Digital Multimedia Broadcast), STIMI (Satellite Terrestial Interactive Multiservice Infrastructure), MediaFLO, ISDB-T (Integrated Service Digital Broadcasting), T-DMB (Terrestial Digital Mulitmedia Broadcast) and DAB-IP (Digital Audio Broadcast) The distribution server 109 is arranged to personalize the distributed content items to the individual users of the multimedia terminals 101, 103. Specifically, the distribution server 109 comprises a recommender functionality which can generate specific recommendations of content items for a group of multimedia terminals 101, 103 which may include between e.g. 10 and 1000 users. Thus, rather than merely distributing content items indiscriminately, the distribution server 109 determines which content items are likely to be appropriate for the individual multimedia terminals 101, 103 and transmits only these content items to the appropriate multimedia terminal 101, 103. Thus, depending on the personalization and recommendation some content items may need to be distributed to a large number of multimedia terminals 101, 103 whereas other content items needs to be transmitted to only one or a few of the multimedia terminals 101, 103.

In the system, the distribution server 109 is operable to dynamically allocate content items for distribution to either the point-to-point or broadcast communication means thereby allowing the advantages of each system to be utilised. Specifically, the personalization suitability of point-to-point distribution can be combined with the resource efficiency of broadcast distribution. Specifically, the broadcast channel 205 can be used to carry items common to many users with the remaining items being carried in point-to-point channels 201, 203. This provides a high recommendation accuracy whilst reducing resource usage and satisfying bandwidth constraints on the broadcast and point-to-point channels 201, 203, 205.

FIG. 3 illustrates the distribution server 109 in more detail.

The distribution server 109 comprises a content store 301 which comprises a large number of content items that are available for distribution to the multimedia terminals 101, 103. It will be appreciated that the content items may be dynamically provided from sources outside the distribution server 109 e.g. via the cellular communication system or via other networks or systems to which the distribution server 109 is coupled.

In addition to the content items themselves, the content store 301 also contains metadata for each content item describing characteristics and properties of the content item and specifically describing the content characteristics. The metadata may e.g. comprise an indication of an artist, genre etc of the content item.

The content store 301 is coupled to a content recommender 303 which is further coupled to a user profile store 305.

The content recommender 303 generates a set of recommendations of content items for each user of the multimedia terminals 101, 103 supported by the distribution server 109.

Specifically, the user profile store 305 comprises a user preference profile for each user in the group of users considered by the distribution server 109. The user preferences may for example indicate the individual user's preferences for different characteristics of content items such as genre, artist, duration etc. The user preference profile may in some scenarios be generated by each user manually entering suitable characteristics for example in response to a questionnaire.

Alternatively or additionally, the multimedia terminals 101, 103 may transmit messages to the distribution server 109 indicating which content items are selected by the user and the distribution server 109 may generate and update user profiles to reflect these selections. For example, a report of a selection of a given content item may result in the distribution server 109 increasing the stored preference value of all properties associated with the selected content item.

It will he appreciated that the distribution server 109 may consider a user to be equivalent to a multimedia terminal 101, 103 such that e.g. the user profiles and recommendations are based on terminal identities. Thus, the terms user and terminal! user equipment! content presentation device etc may in many embodiments be equivalent or identical. Also, the distribution or transmission of a content item to a user typically corresponds to a distribution or transmission of the content item to a terminal! user equipment! content presentation device etc associated with the user. Thus, in some embodiments, a user entity or identity may correspond to a terminal/user equipment entity or identity. In some scenarios, each user may e.g. be linked with a plurality of user equipments/terminals/devices and/or a single user equipment! device! terminal may be linked with a group of users and the user preference profile may specifically be a group profile.

For each user, the content recommender 303 evaluates the content items of the content store in view of the user profile of the user. A suitable reasoning algorithm is used to determine a rank!rating!weight (an estimated preference value for the user for the content item) for each content item. The set of content items recommended for the specific user is then selected as a fixed number of content items having achieved the highest rating. For example, the content recommender 303 may generate a set of recommendations for each user comprising the highest rated ten or twenty content items.

It will be appreciated that any suitable algorithm for determining recommendations may be used without detracting from the invention. Specifically, the content recommender 303 can be based on collaborative filtering, content-based filtering or a hybrid of content-based and collaborative filtering.

In the specific example, the content store 301 comprises M content items and the content recommender 305 rates the N available content items for each user and ranks them according to the generated ratings. The top N content items (N1 < N) are then selected for each user.

The content recommender 303 is coupled to a content set processor 307 which combines the set of recommendations for the individual user into a combined set of recommended content items. The combined set of recommended content items thus include all content items which were included in at least one of the sets for the individual users, i.e. any content item rated in the top N content items for at least one user is included in the combined set.

The combined set may for example include each content item with an indication of how many (and which) users it has been recommended to. Thus, whereas the number of content items in the individual user set is fixed, the number of (different) content items in the combined set may vary.

The content set processor 307 is coupled to a cost processor 309 which for each content item in the combined set generates a communication cost measure. The communication cost measure specifically comprises two cost measures which are alternative cost measures depending on the distribution channel which is selected for the individual content item.

Specifically, a first cost measure reflects a resource cost associated with communicating the given content item using the broadcast communication means. The first cost measure may e.g. be proportional to the data size of the content item.

A second cost measure reflects a resource cost associated with communicating the given content item using the point-to-point communication means. The second cost measure may e.g. be proportional to the data size of the content item.

Furthermore, the relative difference between the first and second cost measure for a given content item transmitted to a single user may reflect a preference characteristic for each communication means. E.g. the basic cost measure associated with communicating a fixed data amount to a single user via the broadcast or point-to-point communication means may be set to reflect the specific preference for transmitting the content item using one of these communication means.

At least one of the first cost measure and the second cost measure depends on the number of users to which the content item is recommended. This reflects the relative resource cost of transmitting a content item to a plurality of users using respectively the broadcast and point-to-point systems.

Typically, the resource usage for point-to-point communication is proportional to the number of multimedia terminals 101, 103 the content item must be transmitted to and thus the resource cost scales proportionally. In contrast, the used broadcast resource is independent of the number of multimedia terminals 101, 103 to which the content should be transmitted. This may therefore be reflected by making the first cost measure for the given content item substantially inversely proportional to the number of users while keeping the second cost measure independent of the number of users. Alternatively, the second cost measure may be made substantially proportional to the number of users while the first cost measure is kept independent thereof.

The content set processor 307 and cost processor 309 are coupled to a communication processor 311 which receives the content items as well as the cost measures for each content item from the content set processor 307. The communication processor 311 is furthermore coupled to a broadcast transmitter 313 which is operable to transmit content items to the multimedia terminals 101, 103 using the broadcast communication means of the cellular communication system and to a point-to-point transmitter 315 which is operable to transmit content items to the multimedia terminals 101, 103 using the point-to-point communication means of the cellular communication system.

The communication processor 311 is capable of dividing the combined content set into a first subset to be distributed to the multimedia terminals 101, 103 via the broadcast communication means and a second subset which in the example is to be distributed to the multimedia terminals 101, 103 via the point-to-point communication means. Thus, for each content item, the communication processor 311 decides whether the content item should be distributed using broadcast communication or point-to-point communication.

The communication processor 311 divides the content items into the two subsets by minimising a combined cost measure which is a combination of the cost measures for the individual content items of the combined set. For each content item, the cost measure is set to the first cost measure if the content item is selected to be distributed using the broadcast communication means (i.e. if it is selected to be in the first subset) and to the second cost measure if the content item is selected to be distributed using the point-to-point communication means (i.e. if it is selected to not be in the first subset but to be in the second subset) . In the example, the combined cost measure may simply be obtained by adding the cost measures of the individual content items but it will be appreciated that in other embodiments a weighting may be introduced e.g. in response to a priority associated with each content item.

As an example, the communication processor 311 may simply calculate a combined cost measure for all possible allocations of content items to the broadcast communication (the first subset) and to the point-to-point communication (the second subset) . The allocation resulting in the lowest combined cost measure may then be selected and the content items distributed accordingly.

In some embodiments, the communication processor 311 select content items for the first subset under a restriction that a communication resource limit of a broadcast communication channel of the broadcast communication system is not exceeded by transmission of the first subset in the broadcast communication channel. Thus, typically, the maximum broadcast capacity that can be used by the distribution server 109 is limited and the allocation of content items to the first subset must be such that this limit is not exceeded. For example, the used broadcast channel may have a fixed capacity of B (kBits/s, say) and the communication processor 311 may seek to allocate content items such that the usage of the broadcast channel is maximised and the usage of the point-to-point channel is minimised while ensuring that the capacity B is not exceeded.

In the following a specific approach for allocating content items to the different communication means will be described.

Let u1, u1, , UN denote the set of users and let c1, c2, c, denote the set of content items. For each content item, the size of the item c1 is denoted by s. This can be measured, for example, in kBytes. The bandwidth requirement for sending the item c over a transmission channel is therefore as1, for a fixed constant a. In general, the cost for sending a content item over the network may depend on other factors than just the data size (e.g. there may be an adjustment depending on the item type -video, audio or text) . We denote the cost of sending item c1 over the point-to-point channel by v1.

The relative cost in sending items over the broadcast channel compared to the point-to-point channels is denoted by constant p. This is included to incorporate differences in fixed costs such as operating the network and bandwidth licensing. Thus, in the example the cost of sending item c over the broadcast channel is given as pv,.

The recommender system is assumed to generate ratings for each user-item pair. The rating of item c1 by user u1 is denoted by r,.. It is assumed that items with lower r1, values are predicted to be of higher preference to the user.

The recommender ranks the recommendations for each user in ascending order and selects the top N} items for delivery to the user.

Let n, denote the number of users to which item c1 is recommended. The cost of sending item c1 over the broadcast channel is pv1, and the corresponding point-to-point cost is proportional to v1n. Also consider the 0-1 state variables x1, xj., , XM that specify the channel option taken for each item: x1 takes value 0 when the channel selected to send item c1 is point-to-point and 1 when it is broadcast. The cost of sending items to the user is in this example given by C(x1.x2 M)_'Jh1J(1X))+P'JxJ.

More generally, a combined cost measure can be used which is substantially given by: C(x,x2.M)=V,fl,(I-XJ)+wJxJ.

where n-denotes a number of users to which content item j is recommended, v. is a resource usage cost measure for transmitting content item j using the point-to-point communication system, w1 is a resource usage cost measure for broadcasting content item j using the broadcast communication system, M denotes a number of content items in the combined set and x, is a binary value which is set to 1 if content item j is included in the first subset and 0 if content item j is not included in the first subset. In the previous example, w, is simply set equal to pv.

Thus, the task of the communication processor 311 is to find the values of x1, x2, ... , x that minimise the cost function C(xl,xI,...,xM) subject to the broadcast channel capacity constraint sv<B After rearrangement, this is equivalent to maximising the utility function VM) = v1x(n1 -p) subject to the constraint s)xJ �= B. This is a standard problem in linear programming and the skiLled person will be aware of various algorithms for solving the problem. For small values of M, a brute force evaluation of all possible content item allocations may be used. For larger, more typical, values of M a method based on Lagrange Multipliers may be used as e.g. described in H. EVERETT, Generalized Lagrange Multiplier Method for Solving Problems of Optimum Allocation of Resources, Operations Research, Vol. 11, No. 3, 399-417.

In some scenarios, the communication processor 311 may simply select the first subset as content items which are recommended to more than a given number of users. For example, if we assume that for all j, v1 = SI, that is the cost measure of sending an item is proportional to its size, then the first cost measure will be lower than the second cost measure if it is to be transmitted to more than a given number of users (for typical values of the preference constant p<2). More generally, the number of users will depend on the relative cost value for the broadcast and point-to-point communication means when transmitting a content item to a single user.

Specifically, where the constant p is less than 1, the described minimisation of the combined cost measure reduces to sending the content items of interest to the most users over the broadcast channel, subject to the channel capacity constraint B. An algorithm for channel allocation under this assumption is illustrated in FIG. 4. The algorithm may be described by the following pseudo code: 1. Set Broadcastltems to be an empty list.

2. Set BroadcastUsage = 0.

3. Set MinimumSize to be the minimum size of an item.

4. Set Sortedlterns to contain all available items sorted by the number of users being recommended the item (n1) so that the top item has the higher number of users.

5. Remove from Sortedltems the top item x1.

6. If n, < p then go to step 9.

7. If BroadcastUsaqe+s1 < B then a. Set BroadcastUsage = Broadcast Usage+s1.

b. Add x to list Broadcastltems.

8. If Sortedltems is not empty and BroadcastUsage + MinimumSize <= B then a. Go to step 5.

9. Send items in Broadcastltems over broadcast and others over point-to-point channel.

The distribution server 109 is furthermore arranged to generate indications for each multimedia terminal 101, 103 which indicates which of the broadcasted content items are recommended for the specific multimedia terminal 101, 103.

This allows the multimedia terminals 101, 103 to determine which of the broadcast content items should be stored and which should be ignored as they are not intended for the specific multimedia terminal 101, 103. Specifically, a message which includes indications of all broadcast content items recommended to a specific multimedia terminal 101, 103 is transmitted to that multimedia terminal 101, 103 using the point-to-point communication means. The communication of these indications may be included with one or more content items being transmitted over the point-to-point communication system or may be transmitted independently of these.

FIG. 5 illustrates the first multimedia terminal 101 in more detail.

The first multimedia terminal 101 comprises a broadcast receiver 501 which is able to receive the broadcast communication channel and which specifically can receive the content items of the first subset.

The first multimedia terminal 101 furthermore comprises a point-to-point receiver 503 which is able to receive a point-to-point communication channel and specifically can receive the content items of the second subset recommended and transmitted to the first multimedia terminal 101. In addition, the point-to-point receiver 503 can receive the message comprising the indications of the content items of the first subset which are recommended to the first multimedia terminal 101.

The broadcast receiver 501 and the point-to-point receiver 503 are coupled to a filter processor 505 which is arranged to select the content items that are indicated to be recommended to the first multimedia terminal 101 from the first subset received by the broadcast receiver 501.

The content recommendations for content items in the broadcast channel may specifically be sent over the point-to-point communication channel to the first multimedia terminal 101 in advance of the content items being broadcast and the filter processor 405 can use this to extract the relevant content items from the broadcast stream when these are received.

The filter processor 505 and point-to--point receiver 503 are coupled to a presentation content set processor 507 which receives the set of content items that are recommended for the specific user of the first multimedia terminal 101 by the distribution server 109. The presentation content set processor 507 is coupled to a presentation processor 409 which can control the presentation of the content items, e.g. as a multimedia clip, to the user. The presentation processor 509 may e.g. present a list of the recommended content items to a user who can then select one or more content items for presentation.

In some examples, all content items of the second subset allocated to communication over the point-to-point communication system are transmitted to the appropriate multimedia terminals 101, 103 including the repeated transmission of content items that have been recommended to more than one multimedia terminal 101, 103.

This approach assumes that sufficient point-to-point communication resource is available. However, in some embodiments the available communication resource of the point-to-point communication channel from the distribution server 109 to the multimedia terminals 101, 103 may be limited (either due to lack of resource in general or due to a specific restriction for the distribution server 109) Thus, in some embodiments, the communication processor 311 is operable to remove at least one content item from the second subset in response to a communication resource restriction of the point-to-point communication system. For example, if the communication resource requirement for transmitting the second subset exceeds the available point-to-point resource, one or more content items may be removed e.g. in order of rating, number of users it is allocated to, data size etc. For example, the communication on the point-to-point communication channel may be restricted to a maximum capacity of A (kBit/s) and content items may be removed from the second subset until the remaining content items can be transmitted within this capacity restriction.

In the specific example, the communication processor 311 does not just remove one or more content items but replaces this with a recommendation of a content item which is distributed by the broadcast communication but which is not in the original recommendation set for the specific user/multimedia terminal 101, 103. Thus, when the communication processor 311 removes a content item of the second subset for e.g. the first multimedia terminal 101, it adds a content item indication for a content item of the first subset. This content item indication can be included in the broadcast indication message that is transmitted to the first multimedia terminal 101 to indicate which broadcast content items are recommended to the first multimedia terminal 101. Accordingly, the first multimedia terminal 101 will use this content item rather than the originally recommended content item thereby ensuring that the user is provided with a sufficient number of recommendations.

Thus, in the example, if the point-to-point channel usage is higher than the target usage A, then users which do not receive one or more recommended content items via the point-to-point communication instead receive content items that were allocated for broadcast even if these content items were not in the highest rated N content items for that user.

Thus, the communication processor 311 selects a first content item which is included in the first subset but not in the set of recommendations generated for the specific user. It then generates an indication of this first content item and sends it to the specific user such that the first content item can be recommended instead of the removed content item. The indication can be included in the message comprising an indication of the broadcast content items of the first set that were in the original content item recommendation set for the specific user (i.e. which were among the top N content items) and can thus be transmitted using the point-to-point communication channel. However, as the communication resource required to transmit the indication is typically much lower than the resource required to transmit a content item a substantial reduction in the required point-to-point communication resource usage is achieved.

The indication may be transmitted with or independently of the transmission of content items to the multimedia terminals 101, 103 using the point-to-point communication channel.

It will be appreciated that different criteria can be used for selecting a first content item of the first set to replace a removed content item of the second set for a first user. Specifically, the communication processor 311 may select the first content item in response to user preference ratings for the first user for content items of the first subset generated by the recommender. E.g., for each content item in the first subset that is not among the highest rated N1. content items, the communication processor 311 can evaluate the rating generated by the content recommender 303 for the first user. The content item with the highest rating can then be selected. Thus, the communication processor 311 will search the lower rated content items to find the one that best matches the user's preferences.

Thus, in the example, once the delivery option for each content item has been determined based on sending the top Np recommendations for each user, the point-to-point bandwidth target usage A may be exceeded. In this case, it is still possible to optimise the number of required point-to-point deliveries by re-considering the recommendation of those items that are less popular. For example, if an item is only being sent to a single user, it may be possible to replace it by a content item further down that user's recommendation list which is already being broadcast on account of it being recommended to other users. This may introduce a distortion in the recommendations provided by the recommender system but may allow more recommendations to be provided than can directly be supported by the point-to-point capacity. Also, the recommender is only making a prediction of user interest and a change such as the one described in the example above can have little impact in terms of user satisfaction.

Furthermore, promoting popular items will often be positive as popular items are, in general, more likeable or interesting than other less popular items. In the particular case of news delivery, it is often the case that people like to be informed about those pieces of news that most people are following.

An example of such an algorithm for using the point-to-point communication channel to provide content item recommendations is illustrated in FIG. 6. The algorithm may be described by the following pseudo code: 1. Set Sortedltems to contain all content items in the second subset i.e. which are intended to be delivered by point-to-point communication. Sort by the number of users being recommended the item (fl,) so that the top item has the LEAST number of users.

2. Remove from Sortedltems the top item x1.

3. For each user u1 requesting this item that is not marked as unavailable: a. Check the next N number of items down his list of ranked items according to preference that are not among the first Np selected for recommendation.

b. Find the best ranked item x7 that is being broadcast.

c. If a item x7 was found then: i. Remove item x3 from the recommendation list of user u1.

ii. Add item x1 to the end of the recommendation list of user u.

iii. Update network deliveries accordingly. else:

iv. Mark user as unavailable.

4. If Sortedltems is not empty, the number of point-to-point bandwidth requirement is greater than the target maximum A and n, of the next item of the list is still below a constant threshold.

a. Go to step 2.

It will be appreciated that in some embodiments, indications of content items not in the user recommendation set may alternatively or additionally be transmitted to the multimedia terminals 101, 103 even if no content items are removed from the second subset.

FIG. 7 illustrates an example of a method of content item distribution for distributing content items using a broadcast communication system or a point-to-point communication system.

The method initiates in step 701 wherein a set of recommendations of content items is generated for each user of a plurality of users.

Step 701 is followed by step 703 wherein a combined set of recommended content items is generated by combining the sets of recommendations.

Step 703 is followed by step 705 wherein a communication cost measure is generated for each content item of the combined set. The communication cost measure for a given content item comprises a first cost measure indicative of a resource cost associated with communicating the given content item using the broadcast communication system and a second cost measure indicative of a resource cost associated with communicating the given content item using the point-to-point communication system.

Step 705 is followed by step 707 wherein a first subset of content items of the combined set is selected for distribution using the broadcast communication system by minimising a combined cost measure being a combination of cost measures for the content items of the combined set. The cost measure for each content item being the first cost measure if the content item is selected to be distributed using the broadcast communication system and the second cost measure if the content item is selected to be distributed using the point-to-point communication system.

It will be appreciated that the above description for clarity has described embodiments of the invention with reference to different functional units and processors.

However, it will be apparent that any suitable distribution of functionality between different functional units or processors may be used without detracting from the invention. For example, functionality illustrated to be performed by separate processors or controllers may be performed by the same processor or controllers. Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality rather than indicative of a strict logical or physical structure or organization.

The invention can be implemented in any suitable form including hardware, software, firmware or any combination of these. The invention may optionally be implemented at least partly as computer software running on one or more data processors and/or digital signal processors. The elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the invention may be implemented in a single unit or may be physically and functionally distributed between different units and processors.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term comprising does not exclude the presence of other elements or steps.

Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Also the inclusion of a feature in one category of claims does not imply a limitation to this category but rather indicates that the feature is equally applicable to other claim categories as appropriate. Furthermore, the order of features in the claims does not imply any specific order in which the features must be worked and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. -35

Claims

1. A content item distribution apparatus for distributing content items using a broadcast communication system or a point-to-point communication system, the apparatus comprising: a recommender generating a set of recommendations of content items for each user of a plurality of users; means for generating a combined set of recommended content items by combining the sets of recommendations; means for generating a communication cost measure for each content item of the combined set, the communication cost measure for a given content item comprising a first cost measure indicative of a resource cost associated with distributing the given content item using the broadcast communication system and a second cost measure indicative of a resource cost associated with distributing the given content item using the point-to-point communication system; allocation means for selecting a first subset of content items of the combined set for distribution using the broadcast communication system by minimising a combined cost measure being a combination of cost measures for the content items of the combined set, the cost measure for each content item being the first cost measure if the content item is selected to be included in the first subset and the second cost measure if the content item is selected not to be included in the first subset.

2. The content item distribution apparatus of claim 1 wherein at least one of the first cost measure and the second cost measure for a given content item is dependent on a number of users of the plurality of users the given content item is recommended to.

3. The content item distribution apparatus of claim 2 wherein the first cost measure for the given content item is substantially inversely proportional to the number of users.

4. The content item distribution apparatus of claim 2 wherein the second cost measure for the given content item is substantially proportional to the number of users.

5. The content item distribution apparatus of claim 1 wherein the allocation means is arranged to select content items for the first subset of content items with a restriction that a communication resource limit of a broadcast communication channel of the broadcast communication system is not exceeded by distribution of the first subset in the broadcast communication channel.

6. The content item distribution apparatus of claim 1 wherein the allocation means is arranged to generate the first subset as content items being assigned to more than a given number of users.

7. The content item distribution apparatus of claim 1 further comprising means for allocating a second subset of content items of the combined set for distribution using the point-to-point communication system, the second subset comprising content items of the combined set not included in the first subset.

8. The content item distribution apparatus of claim 7 further comprising means for removing at least one content item from the second subset in response to a communication resource restriction of the point-to-point communication system.

9. The content item distribution apparatus of claim 7 further comprising: selection means for selecting at least a first content item included in the first subset but not in the set of recommendations generated for a first user; transmitting means for transmitting an indication of the first content item to the first user.

10. The content item distribution apparatus of claim 9 wherein the transmitting means is arranged to transmit the indication using the point-to-point communication system.

11. The content item distribution apparatus of claim 10 wherein the transmitting means is arranged to transmit the indication together with at least one content item of the second subset recommended to the first user.

12. The content item distribution apparatus of claim 9 wherein the selection means is arranged to select the first content item in response to user preference ratings for the first user for content items of the first subset generated by the recommender.

13. The content item distribution apparatus of claim 1 wherein at least one of the first cost measure and the second cost measure for a given content item is dependent on a data size of the given content item.

14. The content item distribution apparatus of claim 1 further comprising means for separately transmitting a first content item recommended to a plurality of users but not included in the first subset to the plurality of users.

15. The content item distribution apparatus of claim 1 further comprising means for transmitting an indication of at least one content item of the first subset recommended to a first user to the first user.

16. The content item distribution apparatus of claim 1 wherein the communication cost measure is substantially given by: C(x1,x, where n denotes a number of users to which content item j is recommended, v1 is a resource usage cost measure for transmitting content item j using the point-to-point communication system, w1 is a resource usage cost measure for broadcasting content item j using the broadcast communication system, N denotes a number of content items in the combined set and x1 is a binary value which is set to 1 if content item j is included in the first subset and to 0 if content item j is not included in the first subset.

17. A content item distribution system comprising a broadcast communication system and a point-to-point communication system, the communication system comprising a content item distributor and a plurality of content item devices wherein the content item distributor comprises: a recommender generating a set of recommendations of content items for each user of a plurality of users, means for generating a combined set of recommended content items by combining the sets of recommendations, means for generating a communication cost measure for each content item of the combined set, the communication cost measure for a given content item comprising a first cost measure indicative of a resource cost associated with distributing the given content item using the broadcast communication system and a second cost measure indicative of a resource cost associated with distributing the given content item using the point-to-point communication system, allocation means for selecting a first subset of content items of the combined set for distribution using the broadcast communication system by minimising a combined cost measure being a combination of cost measures for the content items of the combined set, the cost measure for each content item being the first cost measure if the content item is selected to be included in the first subset and the second cost measure if the content item is selected not to be included in the first subset, means for broadcasting the first subset using the broadcast communication system, and means for transmitting via the point-to-point communication system at least a first of the content items not included in the first subset to a first content item device associated with a user for which the at least one content item has been recommended; and the first content item device comprises: means for receiving the first subset via the broadcast communication system, means for receiving the first content item via the point-to-point communication system, and means for generating a set of recommended content items comprising the first content items and at least one content item of the first subset.

18. The content item distribution system of claim 17 wherein the content item distributor comprises means for transmitting an indication of at least one content item of the first subset recommended to the user associated with the first content item device; and the first content item device comprises: means for receiving the indication, and means for selecting the at least one content item from the first subset in response to the indication.

19. A method of content item distribution for distributing content items using a broadcast communication system or a point-to-point communication system, the method comprising: generating a set of recommendations of content items for each user of a plurality of users; generating a combined set of recommended content items by combining the sets of recommendations; generating a communication cost measure for each content item of the combined set, the communication cost measure for a given content item comprising a first cost measure indicative of a resource cost associated with distributing the given content item using the broadcast communication system and a second cost measure indicative of a resource cost associated with distributing the given content item using the point-to-point communication system; and selecting a first subset of content items of the combined set for distribution using the broadcast communication system by minimising a combined cost measure being a combination of cost measures for the content items of the combined set, the cost measure for each content item being the first cost measure if the content item is selected to be included in the first subset and the second cost measure if the content item is selected not to be included in the first subset.