Method of identifying a radio link
View Patent ↗The invention relates to a Method of identifying a radio link 1,1′,1 ″ of a terminal device 2 to a wireless communication system ( 3 ). The method comprises first step of determining values of parameters of n≧2 radio links, whereby the parameters of each radio link are suitable to quantify at least an aspect of the quality of service of this radio link, the parameters (QoS parameters) being generic QoS parameters usable by different radio network technologies. In a second step a value of a metric is calculated, for each radio link, with the associated determined QoS parameters, whereby the value of the metric defines the overall quality of service of the corresponding radio link. In a third step one of the n≧2 radio links (best radio link) is identified as being the radio link offering the best quality of service by comparing the n≧2 values of the metric calculated in the second step. The method identifies a radio link which offers the best quality of service for a predetermined application in heterogeneous networks characterized by different radio access technologies.
1. A method of identifying a radio link of a terminal device to a wireless communication system, the method comprising the following steps:
a) determining values of parameters of n≧2 radio links, whereby the parameters of each radio link are suitable to quantify at least an aspect of the quality of service of this radio link, the parameters (QoS parameters) being generic QoS parameters usable by different radio access technologies,
b) calculating, for each radio link, a value of a metric with the associated determined QoS parameters, whereby the value of the metric defines the overall quality of service of the corresponding radio link,
c) identifying one of the n≧2 radio links (best radio link) as being the radio link offering the best quality of service by comparing the n≧2 values of the metric calculated in step b),
wherein
determining values of generic QoS parameters is done by
measuring and/or estimating them, or
measuring and/or estimating QoS parameters specific to a radio access technology, and mapping the obtained values into generic QoS parameters.
2. The method according to claim 1 ,
wherein
determining values of generic QoS parameters is done by
receiving generic QoS parameters, or mathematical representations of generic QoS parameters, or
receiving RAT-specific Qos parameters and mapping them into generic QoS parameters.
3. The method according to claim 1 ,
wherein
calculating the metric is done with
generic QoS parameters received from the terminal device and generic QoS parameters determined by the communication system, and/or with
generic QoS parameters received from the communication system and generic QoS parameters determined by the terminal device.
4. The method according to claim 1 ,
wherein
the output values of the metric are scalar values.
5. The method according to claim 1 ,
wherein
the output values of the metric are scalar values, and that larger values indicate a higher quality of service of the associated radio link.
6. The method according to claim 1 ,
wherein
it further comprises the step of creating a quality ranking of the n≧2 radio links on the basis of the n≧2 values of the metric.
7. The method according to claim 1 ,
wherein
the metric is calculated according to
∏
i
(
QoS
determined
(
i
)
QoS
application
(
i
)
)
a
i
whereby QoS determined (i) are the determined values of the generic QoS parameters, whereby QoS application (i) are values of the generic QoS parameters as requested by a particular application running on the terminal device, and whereby α i are weighting factors.
8. The method according to claim 1 ,
wherein
the metric is calculated according to
∏
i
(
f
i
(
x
i
)
)
a
i
,
whereby
x
i
=
QoS
determined
(
i
)
QoS
application
(
i
)
,
whereby QoS determined (i) are the determined values of the generic QoS parameters, whereby QoS application (i) are values of the generic QoS parameters as requested by a particular application running on the terminal device, whereby f i (x) are mathematical functions and whereby α i are weighting factors.
9. The method according to claim 8 ,
wherein
the functions f i (x) are clip functions of the type
clip
i
(
x
)
=
[
0
for
x
i
<
min
i
x
i
for
min
i
<
x
i
<
max
i
max
i
for
max
i
<
x
i
with
x
i
=
QoS
determined
(
i
)
QoS
application
(
i
)
whereby min i represents a minimum allowed value and max i a maximum allowed value of the quantity x i .
10. The method according to claim 9 ,
wherein
determining the parameters of the n≧2 radio links is carried out by the terminal device, and that the terminal device calculates the values of the metric after having received the weighting factors α i from the communication system.
11. The method according to claim 6 ,
wherein
the terminal device transmits a trigger to the communication system if the serving radio link is not the best radio link, to course the communication system to consider or decide a handover to a better radio link as a future serving radio link.
12. A computer program product for identifying a radio link, the computer program product comprising a computer readable medium, having thereon computer program code means, when said program is loaded, to make a computer executable for carrying out the method according to claim 1 .
13. A terminal device for accessing a wireless communication system,
wherein
comprising a computer program product according to claim 12 .
14. A wireless communication system,
wherein
comprising a computer program product according to claim 12 .