METHOD AND APPARATUS FOR DYNAMIC RADIO RESOURCE CONTROLLING
A method and a mobile terminal for communicating with a mobile network element (IWF) comprising communicating with a mobile network element (IWF) using a bearer that is modifiable by a negotiation between the mobile terminal (MS) and the mobile network element (IWF). The data is divided into data units (60) that comprise at least one user data element (61) and at least one status data element (62), said status data element (62) optionally comprising a status indication (63) from the mobile network element (IWF) to the mobile terminal (MS). A need for bearer modification is detected from received status indications (63) in at least two consecutive data units; and a negotiation for bearer modification is initiated, as a response to the detected need for bearer modification.
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This application is a continuation of U.S. patent application Ser. No. 09/397,300, filed Sep. 15, 1999, which claims priority to Finnish Patent Application No. 982002, filed Sep. 16, 1998, and to Finnish Patent Application No. 982643, filed Dec. 7, 1998, the disclosures of which are incorporated herein by reference in their entireties.
FIELDThe present invention relates to a method for communicating with a mobile network element and a mobile terminal implementing the method. The mobile terminal comprises transmission means for communicating with a mobile network element using a bearer that is modifiable by a negotiation between the mobile terminal and the mobile network element, said data being divided into data units that comprise at least one user data element and at least one status data element, said status data element optionally comprising a status indication from the mobile network element to the mobile terminal.
BACKGROUNDMany existing digital wireless or mobile telephone networks make use of time division multiple access (TDMA) to share out radio resources between a number of mobile stations and between a number of channels. For example, in the European Telecommunications Standards Institute (ETSI) GSM standard, a given frequency band is divided in the time domain into a succession of frames, known as TDMA (Time Division Multiplexed Access) frames. The length of a TDMA frame is 4.615 ms. Each TDMA frame is in turn divided into eight consecutive slots of equal duration. In the conventional circuit switched transmission mode, when a call is initiated, a full rate bidirectional traffic channel (TCH/F) is defined for that call by reserving two time slots (1 to 8), in each of a succession of TDMA frames, for the duration of the call. One of these slots provides the downlink from the base station (BS) to the mobile station (MS) whilst the other provides the uplink.
The circuit switched transmission mode in GSM provides for a data transmission rate of 9.6 kbps. However, due to the demand for higher transmission rates, a set of GSM enhancements known as GSM Phase 2+ have been specified by ETSI. One of the main features of GSM Phase 2+ is known as High Speed Circuit Switched Data (HSCSD—specified in GSM 02.34 and GSM 03.34) which achieves an increased data transmission rate by using more than one TCH/F for a single connection (i.e. effectively reserving two or more consecutive time slots in each TDMA frame).
In GSM HSCSD non-transparent connection mode the user can (if the MS supports this feature) request service level up- or downgrading, i.e. request more or less time slots to be allocated for a connection. Provided that the feature is requested in the set-up of a call, service level up- and downgrading is possible during an ongoing call. For example, when setting up a connection to an Internet Service Provider (ISP), the login and authorisation procedures do not require a lot of transmission capacity and could therefore be managed with one time slot connection. When the connection is established and a large file or a www-page (World Wide Web) containing graphics is being downloaded, more transmission capacity is needed. When the file or the www-page are downloaded and the user is reading the information, the need for capacity is not that big anymore, and a small number of time slots are needed.
The advantage of using a correct amount of capacity, i.e. correct number of time slots at each time draws from the fact that the user pays for the connection depending on the amount of time slots used. The less capacity is used, i.e. the less time slots are wasted, and the less the user has to pay. In addition, this approach is advantageous also with respect to the network, since the same resources can be used to facilitate services for a remarkably larger number of users.
However, until now the initiative of radio resource modification (e.g. capacity) is left to the user, which means that in order to be able to properly utilise said radio resource modification, the user should be able to perform relatively complicated call control procedures. On the other hand, the protocols between a mobile station and network entities have been quite definitely specified in the standards, and any new solutions for easier assessment of radio resource modification that require changes to existing standards and/or to existing mobile network elements are not very satisfactory.
Furthermore, to facilitate such up- or downgrading of service level, also the application running in the MS must be adapted to support this feature. This means that for example, a www-browser or an email application in the MS must be adapted to recognise that the connection used is a GSM connection employing multiple time slots, and that service level up- and downgrading is supported by the mobile. So far no such applications exist, and even if some such applications were created, mobile subscribers would always be limited to those few adapted applications available.
SUMMARYNow, a method and a device have been invented, with which the effect of these problems can be considerably reduced.
According to the first aspect of the invention the mobile terminal comprises detecting means for detecting a need for bearer modification from received status indications in at least two consecutive data units; and control means for initiating a negotiation for bearer modification, as a response to the detected need for bearer modification.
In the solution according to the invention, the mobile terminal is arranged to analyze the received data flow, and using the existing information therein to decide whether a correct radio resource is used for the transmission or not. If the radio resource is insufficient, the mobile terminal will initiate negotiations for radio resource upgrading. If the radio resource is excessive, the mobile terminal will initiate negotiations for radio resource downgrading.
Consequently, radio resource modifications can be implemented automatically without the user or the data processing entity connected to the MS necessarily being involved with the control of the properties of the radio resource. Accordingly, the present invention enables easy utilisation of the dynamic nature of the data link.
According to a second aspect of the invention a method for communicating with a mobile network element is presented. The method comprises communicating with a mobile network element using a bearer that is modifiable by a negotiation between the mobile terminal and the mobile network element. The data is divided into data units that comprise at least one user data element and at least one status data element, said status data element optionally comprising a status indication from the mobile network element to the mobile terminal. The method is characterized by detecting a need for bearer modification from received status indications in at least two consecutive data units; and initiating a negotiation for bearer modification, as a response to the detected need for bearer modification.
For a better understanding of the invention and in order to show how the same may be carried into effect reference will now be made, by way of example, to the accompanying drawings, in which;
The invention will, by way of an example, be described in connection with GSM (Global System for Mobile Telecommunications) system using the terms and elements traditionally appearing in this context. Further embodiments in functionally equivalent mobile communication system environments are naturally possible. Among the preferred systems are, for example, GSM derivatives, like DCS (Digital Cellular System for 1800 MHz) and PCS (Personal Communications Service for 1900 MHz).
A set of GSM enhancements specified by European Telecommunications Standards Institute (ETSI) is called ETSI Phase 2+. One of the main work items in phase 2+ is High Speed Circuit Switched Data (HSCSD). HSCSD is an enhancement of the current circuit switched GSM data services to cover higher user rates than 9.6 kbps. The architecture of the HSCSD service is based on the physical layer of the current data services. The increased data rate is achieved by using a combination of more than one full traffic channel (TCH/F) for a single connection.
In the transparent data transmission mode the maximum HSCSD data rate is 64 kpbs using bit transparent protocols. In non-transparent mode the maximum data rate is 38.4 kpbs achieved by using a combination of four TCH/F9.6 channels. After the standardisation of the 14.4 kbps channel coding is completed, the maximum non-transparent data rate is increased to 57.6 kpbs. The effective user data rate of the non-transparent HSCSD data service may be further increased by using GSM data compression that is based on V.42bis algorithm. This compression algorithm increase the effective user data rate to between two and four times the physical user data rate.
Non-transparent mode of HSCSD is realised by modifying the RLP (Radio Link Protocol) and L2R (Layer 2 Relaying) functions to support multiple parallel traffic channels (TCH/F) instead of only one TCH/F, and the RLP frame numbering is increased to accommodate the enlarged data transmission rate, as specified by the ETSI and generally known to a person skilled in the art.
To couple the Terminal Adapter Function with Interworking control procedures, a group of GSM Bearer Capability Information Elements (BCIE) need to be defined during the call set-up procedure. The BCIE comprise a parameter User Initiated Modification Indication (UIMI), which is relevant between the MS and IWF. The value of UIMI indicates whether the user would like to be able to modify the value of maximum number of traffic channels during a connection, and in positive case also the maximum number of time slots available for upgrading the connection. Among parameters negotiated in the call set-up procedure are also the Fixed Network User Rate (FNUR), which defines the user rate between the IWF and the fixed network, and the Wanted Air Interface User Rate (WAIUR) defining the air interface user rate between the MS and IWF.
If the parameter UIMI has been given a non-zero value, during a HSCSD call the user may request the network to change the current maximum number of traffic channels and air interface user rate parameters.
In the system according to the embodiment of the invention, the mobile station monitors the data flow transferred over the air interface, and based on the monitoring results intelligently controls e.g. the number of the time slots used for the connection. In the following, some embodiments of the invention are discussed. The radio resource used for a connection is hereafter referred to as a bearer.
According to the invention the data already available in data units is used by the MS to derive the decision whether bearer modification is necessary. To demonstrate the structural division of transceived information, data transfer process in a GSM system supporting HSCSD service is studied.
The decision on whether a correct radio resource is used could also be made in the IWF and be indicated to the MS in the header 51 of the RLP frame. Anyhow, this seems to be an unnecessary association between a link layer protocol and a non-link-layer function, and as conceivably bringing about some changes to the protocol, would not be very satisfactory.
In
The L2R and RLP entities have buffers which may become full to a predetermined threshold for a number of reasons, e.g. severe radio fading, failure or slowness of DTE to react to end-to-end flow control, or certain RNR conditions. When this predetermined threshold is reached, a flow control active condition is sent to the associated DTE, which is then prevented from sending any data. Subsequently, the flow control inactive condition is sent to the associated DTE when the L2R or RLP entities have indicated that there is sufficient free capacity in their buffers for data flow from the associated DTE to proceed. A status octet 62 of a L2R PDU comprises a flow control indication bit 63 indicating whether the flow control in the DTE in the opposite end is active or inactive. A status octet may also comprise a break indication bit indicating that the rest of the PDU is empty, i.e. the PDU is not full of user data.
In the solution according to the invention, the user has an opportunity to enable or disable the use of user initiated bearer modification. When the modification is enabled, the mobile station according to the invention starts monitoring the contents of the consecutively received data units, here the L2R PDUs. In the first embodiment of the invention, the MS will especially monitor consecutively received flow control indication bits. Whenever it seems that the flow control in the IWU end is active for a long period, the MS deduces that the data rate should be downgraded and initiates a bearer downgrading negotiation. If the flow control is not active or has not been active for some time, the MS will initiate a radio resource upgrading negotiation. The decision, on when the flow control is active or inactive for a long time, i.e. when the bearer modification (upgrading or downgrading) in this case is necessary, can be derived in many ways. Next one of the possible ways is described.
The flow chart of
The embodiment of
The flow chart of
The RLP-header of a PDU comprises a S-bit that indicates whether the PDU comprises a status octet or not. Status octets are inserted in the character stream 30 whenever a status change needs to be transmitted. If the PDU is full of data, it does not comprise the status octet. In the embodiment the effective user data rate is derived in predefined intervals T. This means that a timer t is running for a period of T at a time and after the elapse of the time limit T, the estimation of effective user data rate is restarted. In step 810 two counters SE and SF are initialised, and in step 815 the timer t is started. In step 820 the count of the timer t is checked, and whenever the time limit T has elapsed, the process will go to step 845. Until the time limit T has elapsed, a next PDU will be received (step 825) and the indication Sbit, indicating whether the PDU comprises a status octet or not, is checked (step 830). If in step 835 the Sbit indicates that the PDU does not comprise a status octet, the counter SF is incremented (step 840). If the Sbit indicates that PDU comprises a status octet, the contents of the PDU has to be checked more thoroughly (step 860). The status octet comprises status bits SA, SB and X, and a 5-bit code which indicates the location of the next status octet or that the remainder of the PDU is empty. If the indication of the remainder of the PDU being empty is found (step 865), the counter SE is incremented (step 870), otherwise no incrementation is done. After step 865=No or after step 870 the process will continue from step 820. Alternatively the step 865=No could go to step 840 (not shown in the Figure).
When at step 820 it is noted that the time limit T has elapsed, it continues at step 845 in which the current value of the counter SF is divided with the reading t of the timer to derive the rate sf at which PDUs that are full of user data are received. Moreover, at step 875 the current value of the counter SE is divided with the reading t of the timer to derive the rate se. Then it is checked if the derived value of sf is greater than a predefined threshold TH1 (step 850), and if so the MS will initiate a bearer upgrading process (step 855). If sf is not greater than a predefined threshold TH1 another comparison is made (at step 880) to see if the derived value of se is greater than a predefined threshold TH2, and if so the MS will initiate a bearer downgrading process. If the threshold TH1 or TH2 is not exceeded, the process will continue from step 810.
The above is a description of the realization of the invention and its embodiments utilizing examples. It is self evident to a person skilled in the art that the invention is not limited to the details of the above presented embodiments and that the invention can be realized also in other embodiments without deviating from the characteristics of the invention. The presented embodiments should be regarded as illustrating but not limiting. Thus the possibilities to realize and use the invention are limited only by the enclosed claims. Thus different embodiments of the invention specified by the claims, also equivalent embodiments, are included in the scope of the invention.
Claims
1. A mobile terminal comprising:
- a transceiver configured to receive a plurality of data units originating from a network element, wherein at least one data unit of the plurality of data units includes a status bit indicating that flow control in the network element used to transmit the at least one data unit is active or inactive; and
- a data processing unit configured to analyze the status bit; and determine whether to request a change in a data rate at which the transceiver receives the plurality of data units based at least in part on the analysis of the status bit.
2. The mobile terminal of claim 1, wherein the data processing unit is further configured to request a bearer downgrade if the flow control is active for a predetermined amount of time.
3. The mobile terminal of claim 1, wherein the data processing unit is further configured to request a bearer upgrade if the flow control is inactive for a predetermined amount of time.
4. The mobile terminal of claim 1, further comprising a counter, wherein the data processing unit uses the counter to track a number of consecutive status bits having a same value.
5. The mobile terminal of claim 4, wherein the data processing unit is further configured to request the change in the data rate if the number of consecutive status bits having the same value is greater than a predetermined threshold.
6. The mobile terminal of claim 1, further comprising a timer, wherein the data processing unit is configured to initiate the timer when a second received status bit differs from a first received status bit.
7. The mobile terminal of claim 6, wherein the data processing unit is further configured to request the change in the data rate if a time kept by the timer exceeds a threshold value.
8. The mobile terminal of claim 1, wherein analyzing the status bit comprises comparing the status bit to a reference value.
9. The mobile terminal of claim 1, wherein the transceiver is further configured to receive a user initiated modification indication, and further wherein the data processing unit is configured to activate or deactivate the analysis of the status bit based on the user initiated modification indication.
10. A method for determining a rate for exchanging data, the method comprising:
- receiving a plurality of data units originating from a network element, wherein at least one data unit of the plurality of data units includes a status bit indicating that flow control in the network element used to transmit the at least one data unit is active or inactive;
- analyzing the status bit; and
- determining whether to request a change in a data rate at which the plurality of data units is received based at least in part on the analysis of the status bit.
11. The method of claim 10, further comprising requesting a bearer downgrade if the flow control is active for a predetermined amount of time.
12. The method of claim 10, further comprising requesting a bearer upgrade if the flow control is inactive for a predetermined amount of time.
13. The method of claim 10, further comprising using a counter to track a number of consecutive status bits having a same value.
14. The method of claim 13, further comprising requesting the change in the data rate if the number of consecutive status bits having the same value is greater than a predetermined threshold.
15. The method of claim 10, further comprising initiating a timer when a second received status bit differs from a first received status bit.
16. The method of claim 15, further comprising requesting the change in the data rate if a time kept by the timer exceeds a threshold value.
17. A network element for using in controlling a rate of data exchange, the network element comprising:
- a transceiver configured to provide a plurality of data units to a mobile station, wherein at least one data unit of the plurality of data units includes a status bit indicating that flow control used to provide the at least one data unit is active or inactive; and receive a request for a change in a data rate at which the plurality of data units are provided from the mobile station, wherein the request based at least in part on an analysis of the status bit by the mobile station; and
- a data processing unit configured to change the data rate based on the received request.
18. The network element of claim 17, wherein the data processing unit is further configured to determine whether the flow control is active or inactive.
19. The network element of claim 17, wherein the network element comprises an inter-working function.
20. The network element of claim 17, wherein the plurality of data units is provided through a plurality of data streams.
Type: Application
Filed: Apr 29, 2008
Publication Date: Oct 23, 2008
Applicant:
Inventors: Marko Valo (Tampere), Juha Rasanen (Espoo)
Application Number: 12/111,643
International Classification: H04J 3/00 (20060101);