US 20080115125 A1
Methods and apparatus including a virtual machine and a compression network platform are provided especially for improving the application of compression algorithms and unique identifiers for algorithms, bytecode and HTTP common phrases of HTTP messages utilized to advantage in wireless networks. In particular, a given virtual machine need only identify to a receiving virtual machine the unique identifier for one of an algorithm, a static dictionary or a hash for decompressing a received data signal. Universal decompressor virtual machines may receive uploaded compression algorithms, bytecode identifiers or static dictionary identifiers and the like from proxy call session control functions of a wireless network, the compressing machine or a compression network platform resource which in one embodiment may comprise an IANA database. The methods and apparatus may find particular application in improving the efficiency of presence/group list management.
1. A network platform for maintaining a database registry of at least one compression and decompression algorithm, a static dictionary, and respective algorithm and dictionary identifiers for use at end locations for compression or decompression of data signals, the network platform comprising:
a data transceiver coupled to a controller for receiving and transmitting data signals;
a memory for storing the compression and decompression algorithm, static dictionary and algorithm and static dictionary identifier data for transmission as data signals; and
the controller, responsive to a request for a particular compression application, for matching the application to an algorithm or a static dictionary stored in memory to determine algorithm, corresponding identifier or a static dictionary and corresponding identifier data for transmission by the data transceiver.
2. A network platform as recited in
3. A network platform as recited in
4. A network platform as recited in
5. A network platform as recited in
6. A network platform as recited in
7. A virtual machine for use in a wireless network comprising:
a decompression controller for controlling decompression of a received data signal in accordance with one of a static dictionary or a decompression algorithm;
a memory for storing one of a static dictionary or a decompression algorithm according to a unique identifier of the static dictionary or decompression algorithm;
the decompression controller, responsive to a received data signal, determining the unique identifier and retrieving the associated static dictionary or the decompression algorithm; and
if the decompressing algorithm or static dictionary are not stored in memory by unique identifier, the controller requesting the unique identifier and the associated static dictionary or algorithm from a remote location.
8. The virtual machine as recited in
9. The virtual machine as recited in
10. The virtual machine of
11. A method of compressing a HyperText Transfer Protocol message portion including a common phrase comprising:
storing a unique identifier in a static dictionary in memory of a virtual machine representing a common message phrase;
transmitting toward a remote virtual machine the identifier for the common message phrase in conjunction with the application of a compression algorithm, the compression algorithm also identified by a unique identifier in place of the common phrase of the message portion of the HTTP transmission.
12. A method of decompressing HyperText Transfer Protocol message portion including a common phrase comprising:
storing a unique identifier in a static dictionary in memory of a virtual machine representing a common message phrase;
receiving from a remote virtual machine the identifier for the common message phrase in conjunction with the application of a compression algorithm, the compression algorithm also identified by a unique identifier;
and replacing the identifier in the HTTP data received from the remote virtual machine with the common phrase of the message portion of the HTTP stored in memory.
13. A method of establishing a compression method for use at user equipment comprising
transmitting a registration request including dictionary definition from the user equipment,
receiving a response including a dictionary definition and
transmitting subsequent messages from the user equipment if the dictionary definitions agree.
14. A method as recited in
15. A method as recited in
16. A method as recited in
17. A method for use in user equipment for obtaining an updated dictionary comprising
establishing a session with a server for retaining dictionary data via a proxy server,
receiving an updated dictionary responsive to service provider control.
18. A method as recited in
19. A method as recited in
20. A method as recited in
The technical field relates to wireless communication networks and, in particular, to methods and apparatus for facilitating and optimizing the application of compression, for example, to data signal compression and in internet applications including JAVA virtual machine bytecode and hypertext transfer protocol (HTTP) applications in such networks.
Generally, wireless communication networks suffer a disadvantage in comparison with wired communication networks because wireless communication networks must utilize valuable radio frequency spectrum for the transmission of signals to wireless mobile devices (including portable terminals such as computer terminals or personal communication devices). Spectrum is expensive to purchase as exemplified by the wireless communications RF spectrum sales of the 1990's. Moreover, the greater the application of uncompressed signals, power for transmitting signals in the purchased RF spectrum can be wasted along with the spectrum utilization increase. Further complicating and making the need for compression even greater in a wireless communication network, the applications for such mobile devices have greatly expanded as wireless communications have, in many instances, replaced wired communication devices because of the great, almost unbounded popularity of the devices and the features that such devices may provide. Consider, for example, currently available mobile devices providing input/output for taking and receiving digital photographs (which can be compressed in accordance with known JPEG compression techniques), receiving downloaded MPEG compressed movie streams for a subscriber's viewing pleasure, the opportunity to short text message to “buddy lists” of friends, associates and family members having mobile devices, download, store and play compressed digital music in stereo of the subscriber's choice and so on.
Also consider the differences between text compression, for example, the compression of a voice message converted to text or a text document or a text message versus JPEG or MPEG compression. The former needs to be lossless, that is, the message at the transmitter ideally should be perfectly reproduced at the receiver after compression and decompression. On the other hand, JPEG and MPEG image compression follow a different philosophy. The compression/decompression process need not be perfect and some original image data may be lost intentionally but only such that the received image is practically identical to the transmitted image and any loss is not perceptible to the viewer.
In a virtual machine, bytecodes are known for representing the machine language of, for example, a Java virtual machine. The bytecode stream represents a sequence of instructions for the virtual machine. HTTP is a known protocol for internet address and command processing. In wireless communications involving the network, there is a need for compression of such data signals. These types of data streams are akin to text compression where there is a requirement for lossless compression/decompression processes.
Many of the new applications for mobile devices have centered around an implementation of a session initiation protocol (SIP) described, for example, by RFC 3261. SIP provides a protocol for negotiating session parameters between session endpoints, for example, such as setting up and tearing down Voice over IP sessions between VoIP phones or sessions in which a camera image is transmitted from one cell phone to another. Moreover, data signal transmission and data compression are also known from such well known compression algorithms as ZLIB (RFC 1950), DEFLATE (RFC 1951) and GZIP (RFC 1952), and other compression algorithms and techniques, all of which are well known to the Internet community at large.
More recently, progress has been made in the development of standard compression interfaces and techniques for signal compression as exemplified by the efforts described by RFC 3320 and RFC 3321. Also, recently, a session initiation protocol (SIP) and a session description protocol (SDP) static dictionary has been described in RFC 3485. Moreover, a so-called universal decompressor virtual machine (UDVM) has been described, much like a Java virtual machine, for running decompression algorithms and to provide almost unlimited flexibility for choosing how to compress/decompress a given item of data. With UDVM, both terminal ends, for example, two mobile devices exchanging photographs or a mobile device gaining access to a video-on-demand movie server must know what compression/decompression the other end is using for the data signal; otherwise, the compression/decompression provided by the UDVM's will not function at an optimum level. On the other hand, in SigComp as applied in SIP, headers as well as message bodies may be compressed. Yet, network elements need to read the SIP headers for routing and other purposes. Consequently, there is a problem with end-to-end transmission for SIP because a network element may have to decompress headers along a route to an end point. Consequently, there may be a problem with the applicability of SigComp end-to-end as would be required as applied in SIP.
Also, in accordance with the third generation partnership project, 3G PP, for the global system for mobile communications (GSM) and which can be used in related UMTS standards, an internet protocol (IP) multimedia subsystem (IMS) has been defined for multimedia applications, for example, per TS 23.228, 24.228 and related technical specifications. There is proposed, for example, a proxy call session control function (P-CSCF), an interrogating CSCF (I-CSCF) and a serving CSCF (S-CSCF). SIP messages between one's handset and its associated P-CSCF may be compressed as are SIP messages between another person's handset and its P-CSCF. But between P-CSCF's, the SIP messages are generally uncompressed because as explained above the headers are needed for routing and there is limited motivation to apply SigComp to a portion of a message and not the whole. These control functions are known for use in home and visited networks by mobile devices for multimedia services as an outbound proxy (the first SIP-layer point of contact for a mobile device in, for example, a general packet radio service (GPRS) network). These control functions may be accessed by a mobile device that would want to engage in a real-time interactive multimedia application with a mobile device in the same or in another wireless communication network. The virtual machines such as the UDVM mentioned above are resident in, for example, the mobile device and the P-CSCF. The capabilities of both ends of a communication path should be consistent with one another to successfully restore compressed content to its original form.
Presence is becoming increasingly important to wireless network features and services. Presence relates to registration of a mobile device that is turned on and in a mode for receiving communications which may be standard voice calls or limited to receiving, for example, text messages from a “buddy.” As alluded to above, one or more “buddy lists” may be input by a wireless subscriber for friends, associates and family of the subscriber and used to signal “presence” information among “buddies.” The wireless subscriber will typically wish to receive updates regarding his/her buddies' presence status, as presence status is dynamic. For example, a college student may receive presence information indicating that a given buddy is currently not available for voice calls but can receive text messages. Based on this information, the student signals that “buddy” by text message to meet him/her in the library at 10:00 AM. In so doing, eXtensible Markup Language (XML) (not visible to the user) is commonly used to represent contact information, such as an address book, each of which may be delimited with the string <contact> at the beginning of the string of contacts and </contact> at the end of the string. Inside one of the contact strings, <name> and </name> may be used to identify a name of a “buddy” or contact. Presence information, bracketed by additional delimiters, may be stored with the contact information. SIP has been identified as a suitable vehicle for publishing one's presence information and for receiving updates regarding a buddy's presence. HTTP has been identified as a suitable vehicle for managing one's buddy lists. So for presence and buddy list management, SIP and HTTP messages are launched and the message bodies may be XML documents.
Consequently, even with all these improvements in the art of providing compression techniques and virtual and other machines for providing compression/decompression in accordance with alleged unlimited flexibility, there remains an opportunity to facilitate, if not to optimize, the use of compression via application, for example, of static dictionaries and other techniques for compressing various signals, bytecode, SIP and HTTP messages, XML document and other data signals used in a wireless communications network environment where the need for compression is the greatest.
Several embodiments will now be briefly described for facilitating compression/decompression of various data utilized in a wireless telecommunications network. According to one embodiment, a universal compression network platform (CNP) is provided as a wireless network resource for compression and decompression which even any UDVM or other virtual machine may use as a resource for assuring that a given static dictionary or compression or decompression algorithm are current. In its database may be maintained the latest version of a compression and associated decompression algorithm and/or static dictionary or other compression/decompression tool for universal access in a manner similar to the manner in which regional databases and servers have been provided for number portability in the United States. Alternatively, a compression network platform (CNP) may be implemented on a wireless communications network basis, for example, by each public land mobile network (PLMN) internationally or preferably on a more global basis. In a network by network implementation, each wireless network may agree to exchange and maintain their CNP databases by mutual agreement with the latest revisions and techniques. In this network by network embodiment of a CNP, there may be a problem with roaming among networks and whether the visited network needs to decompress SIP messages or in stead just forward them to a home network via GPRS roaming. On a more global basis, as was utilized in number portability, a global CNP may be accessed by all networks. All such CNP's are preferably provided with redundancy and in different regions of a country for purposes, for example, of disaster recovery. A UDVM at each end of a communication channel may have on hand the bytecode and dictionary or dictionaries that each needs by conducting a dialog between them, and, in the event of a difference resolve their difference between them or utilize a CNP.
In accordance with another embodiment, rather than uploading/downloading bytecodes to a virtual machine, for example, associated with a mobile device or a P-CSCF, a compression application of the bytecode may be applied, for example, to compress the bytecode for uploading/downloading rather than the current method of transmitting the bytecode itself to a far end virtual machine. According to one aspect of this embodiment, the compression technique may comprise a hash of the bytecode, for example, in a manner similar to that described as a static dictionary in RFC 3485 for SIP and SDP or signal compression generally as described by RFC 3320 and 3321. According to another aspect, there may be a publicly-available registry for storing the algorithm, hash or static dictionary for the byte code, for example, as a universal resource name as would be stored in the Internet assigned numbers authority (IANA) database registry. According to the first embodiment, the algorithm, hash or static dictionary for bytecode may be stored along with its current version number and a unique identifier in a CNP described above for universal access by any virtual machine.
In accordance with yet another embodiment, there is provided a means for receiving bytecodes and retaining them for long-term utilization by a virtual machine. If a UDVM, for example, does not have a copy of a bytecode it needs for receiving a given compressed data signal transmission, the UDVM receiving the bytecode first requests the bytecode compression method from the transmitting compression virtual machine. If it cannot receive the method from the transmitter machine, according to another aspect, it may receive a unique identifier for the compression method and refer to an IANA registry or a CNP registry as suggested above according to the first and second embodiments and receive the method from them along with its identifier and version number. According to another related aspect, a new bytecode, unique identifier and its version may be propagated generally to virtual machines for long term storage therewith and subsequently referred to by its unique identifier at a compression/decompression virtual machine, for example, by a CNP or via IANA or other registry.
In accordance with yet another embodiment, consider hypertext transfer protocol (HTTP) having a header and a message payload. An example of XML content is contact information such as an address book in XML in which each contact is delimited by the string <contact> contact data </contact>. Inside the XML contact, there may be <name> Ronald Reagan </name> and email addresses and telephone numbers, home addresses and the like for Ronald, each delimited by its own tag. In this embodiment, a static dictionary may be provided for compression of the HTTP payload or message portion. In particular, this embodiment recognizes common phrases used in the message portion such as tags from application-specific XML schema. Known compression algorithms for HTTP such as DEFLATE and GZIP may be augmented in this embodiment to provide a static dictionary for such common phrases which may be stored at the compression and decompression virtual machine and accessed as above from a CNP or via IANA or other registry. Consequently, consider the example of presence/group list management. Presence covers such concepts as online/offline status, preferred means of communication (for example, voice or text messaging). Group list management includes the afore-mentioned contact or “buddy” lists. For example, a user wants to maintain one or more contact lists. For example, a subscriber's contacts may be grouped into separate lists (e.g. for colleagues and friends, or according to a variety of shared interests. So there is a need to manage a contact list or preferred sub-list of contacts who one contacts more or less frequently. The virtual machine contained within the mobile device or its server will have access to and permanently store the known compression algorithm along with its added feature of accessing a static dictionary for translating the common phrases into transmittable address data (in shorter form than the common phrase data) that may be used at the decompression end to address a look-up table of the static dictionary for decompression of the common phrase.
These and other aspects and embodiments will become clear from referring to the drawings and the detailed description of the embodiments which follow.
Referring first to
User equipment or mobile device as used herein refers to any known mobile terminal which may comprise terminals limited to voice telephony but is not to be considered so limited as user equipment may include personal computers, personal communications devices and other devices having, for example, multimedia and computational capability. Similar reference characters are used throughout the drawings to designate similar elements and the first number of a reference character designates where that element first appears. For example, user equipment 115 first appears in
Preferably, the data signals, for example, text or content, to be transmitted are to be compressed for transmission through the wireless medium. Both mobile devices 115 and 125 are assumed to be visiting different wireless networks. Mobile device A 115 is visiting network 110 and mobile device B 125 is visiting network 140. Visited network 110 by mobile device 115 has proxy CSCF 135-1 and general packet radio service GPRS 165-1. Mobile 115's home network 120 has interrogating CSCF 145-1, serving CSCF 155-1 and optional interrogating CSCF 145-2. Ideally, each wireless network 110, 120, 130, 140 may agree to exchange and maintain their CPN databases by mutual agreement with the latest revisions and techniques in accordance with one embodiment. CPN 150 may be shared by all networks. But, in another embodiment, there may be a plurality of these CPN platforms and databases, and they may be redundant within each public land mobile network (PLMN). Such CPN's 150 are preferably provided with redundancy and in different regions of a country for purposes, for example, of disaster recovery. Not shown in
Mobile device 115 in accordance with an aspect of the invention shares its compression algorithm, static dictionary or other compression technique by a unique identifier with a network platform or with another mobile device 125 with which it wishes to communicate. In the event the far end (i.e. network platform or mobile device 125) does not understand the unique identifier, it may request the mobile device 115 to transmit the algorithm or static dictionary used (along with its identifier) or receive the compression method and identifier from a UDVM at P-CSCF 135-2 by identifier look-up. P-CSCF 135-1 may also be a check point to be sure there is consistency among points of compression and/or decompression. Also, in accordance with an aspect of the invention, when all else fails, a CNP 150 may be referred to by a virtual machine of mobile device 115 and within mobile device 125 for an appropriate compression/decompression tool that is application dependent. P-CSCF 135-1, 135-2 or CNP 150 may transmit identifiers or algorithms and identifiers to mobile devices 115, 125 for storage therein depending on the needs.
In accordance with another embodiment which also may be described with reference to
According to another aspect which may be described with reference to
In accordance with yet another embodiment, consider hypertext transfer protocol (HTTP) having a header and a message payload. In this embodiment, a static dictionary may be provided for compression of the HTTP payload or message portion. In particular, this embodiment of a compression method recognizes common phrases used in the message portion such as tags from application-specific XML schema. Tags may be used, for example, to delimit name, email address, telephone number, facsimile number and so on. In order to provide a positive user experience, it may be expedient to allow each subscriber to have a large number of contacts and to organize their contacts into multiple buddy lists. The tags that delimit the data can easily become voluminous. Consequently, an application of this embodiment is presence/group list management in a wireless network. As defined above, presence comprises online/offline status, preferred means of communicating (such as text message or voice) and other data about the user of a mobile device such as location of the mobile device. Known compression algorithms for HTTP such as DEFLATE and GZIP may be augmented in this embodiment to provide a static dictionary for such common phrases which may be stored at the compression and decompression virtual machine and accessed as above from a CNP or via IANA or other registry. In particular, address data for a look-up table of the static dictionary may be transmitted in place of the common phrase. On decompression at the receiving end, the address data indexes the look-up table of the static dictionary and retrieves the common phrase. Consequently, the user of a mobile device may enter a contact list or update a contact list for, for example, short message services and the virtual machine contained within the mobile device or its server will have access to and permanently store a known compression algorithm for delimiting tags and other data along with its added feature of accessing a static dictionary for translating other common phrases into transmittable address data for indexing a look-up table that may be used at the decompression end for decompression.
The P-CSCF 135 forwards the REGISTER request within an IMS core, not shown, which may issue an authentication challenge. As shown, a P-CSCF 135 then forwards the authentication challenge to the user equipment 115 as the 401 Unauthorized message in
After a handset (user equipment) successfully attaches to a wireless network (not shown to keep
In the 401.Unauthorized challenge message, the receiver, the P-CSCF 135, tells the user equipment UE 115 what dictionaries it has on hand in its “state=” parameter definition. In
In principle, user equipment 115 in
Note that according to both
Continuing the discussion of
Thus there has been shown and described several approaches for the optimized application of static dictionaries which may be utilized in concert with dynamic compression/decompression algorithms in a wireless network to considerable advantage for different purposes such as in so-called presence applications. The following set of claims should not be deemed to be limited to the embodiments described above. Alternative embodiments may come to mind to one of ordinary skill in the art for application in alternative or later generation wireless networks.