DYNAMIC ALLOCATION OF SPECTRUM SENSING RESOURCES IN A COGNITIV RADIO
NETWORK
Description
Field of the invention
The invention relates to a method, a base station apparatus and a eomputer
readable storage medium for communicating in a wireless telecommunication
network, more specifically to a method of using white -space frequencies for wireless
telecommunication.
Background and related art
The ultra-high frequency (UHF) white space frequencies are commonly used for
digital video broadcasts (DVB-TJ and wireless microphones. The UHF frequency
band lies in the range from 470-790 MHz. The DVB-T TV broadcasters do not use
the whole frequency range for DVB-T broadcasting. Wireless microphones may also
communicate in this frequency range and may be switched on and off dynamically
without interfering with other wireless microphones and/or DVB-T servers. Because
of the relatively small coverage area of a wireless microphone the use of a certain
frequency for a wireless microphone has not to be registered at a central network
entity. The same applies in some regions or countries for other devices with a small
coverage area.
US 2008/1 59208 A 1 discloses a method and apparatus for allocation of shared
spectrum in a wireless communication system using a radio frequency beacon
signal that is transmitted between access points of the wireless communication
system.
EP 1 750 466 A 1 discloses a communication network including a set of user
terminals such as a cellular network of a WLAN, The communication network
includes a system for dynamically controlling spectrum usage.
Summary of the invention
It is the object of the present invention to provide an improved method of
communicating in a wireless telecommunication network, an improved base station
apparatus and an improved computer readable storage medium. This object is
achieved by the method, the base station apparatus and the computer readable
storage medium according to the independent claims. Embodiments of the invention
are given in the dependent claims.
The invention provides a method of communicating in a wireless telecommunication
network, wherein the method comprises the following steps;
According to the invention a control channel is established at a control channel
frequency in a first frequency band between a wireless terminal and a base station
of the wireless communication network. The first frequency band is exclusively used
for wireless telecommunication and may for example be a GSM, UMTS or LTE
network. The wireless terminal may for example be a mobile phone, a PDA or a
mobile computer. The control channel is used for transmitting control information
from the base station to the wifeless terminal and vice versa. Control information
may for example be information about a communication channel, which is assigned
from the base station to the wireless terminal, or for example data being relevant for
the control mechanisms in the base station requested by the base station from the
wireless -terminal. In genera! the control channel functions: like a control channel as
known from standard control channels in GSM, UMTS or LTE
In a second step information is gathered about a second frequency band. The
information is indicative of at least a first portion of the second frequency band not
being allocated to at least one other device and/or server. The second frequency
band is preferably a white space frequency band between 470 and 790 MHz, which
corresponds to the above mentioned UHF white space frequency band. In other
words, information is gathered, if at least a first portion of the second frequency
hand is not used by at least one other device for wireless communication, it is to be
noted that the at least one other device may also be a DVB-T TV broadcast sender
ox any other broadcast sender, which only transmits signals on the second
frequency band but does not receive signals on the second frequency band. The at
least one other service may for example be any TV or radio broadcast service such
as DVB-T.
In a third step it is determined, if the traffic load in the first frequency band Is above
a traffic load threshold in this step the traffic load in the first frequency band is
determined because it may be advantageous to source out some traffic from the first
frequency band to the second frequency band.
In a fourth step control channel data is transmitted via the control Ghanne! from the
base station to the wsreiess terminal, if the traffic load in the first frequency band is
above the traffic load threshold, The control channel data comprises a
communication channel frequency in the second frequency band of a
communication channel. The control channel data is in other words Indicative of a
communication channel frequency in the second frequency band of a
communication channel. In other words, the base station transmits a frequency of
the second frequency band to the wireless iermina! via the control channel for
sourcing out traffic from the first frequency band to the second frequency band by
transmitting the communication channel frequency, wherein the communication
channel frequency lies in the second frequency band. The communication channel
is adapted for being used for communication of the wireless terminal with the base
station. The communication channel may for example be used for telephone calls,
data transmission, e.g. internet data transmission, or any other telecommunication
being established from the wireless terminal to another device via the base station.
In a fifth step a communication channel at the communication channel frequency is
established between the wireless terminal and the base station, if the traffic load in
the first frequency band is above the traffic load threshold. Si is to be noted that the
last two steps are only performed if the traffic load in the first frequency band is
above the traffic load threshold. This means communication is only outsourced to
the second frequency band from the first frequency band in case the traffic bad in
the first frequency band has exceeded the traffic load threshold.
The method according to the invention is advantageous because in case of high
traffic loads some traffic may be outsourced to the first frequency band, which is a
white space frequency band, e.g. the UHF white space frequency band reaching
from 470-790 MHz. The first frequency band, where the control channel is
established is preferably a frequency band, which Is licensed to the operator of the
wireless telecommunication network. Contrary to the white space frequency band
the first frequency band may only be used by this operator of the wireless
telecommunication network.
When sourcing out traffic to the second frequency band, which is the white space
frequency band, care has to be taken not to disturb any other communication in the
white space frequency band. This fe avoided by gathering the information about the
second frequency band. Because the frequencies in the white space frequency
band are not necessarily registered at a centra! entity, information of used and
unused frequencies must be gathered. The gathering may comprise for example
sensing for communication in the second frequency band or accessing a database,
where used or allocated frequencies in the second frequency band are stored. Once
again, it is emphasized that the at least one other device may for example also be a
sender of digital video or audio broadcasts. The allocation of a frequency in the
second frequency band may also be performed by one device without
communicating the allocation to another device. This may be for example a wireless
microphone, which aliocates itself a certain frequency in the second frequency band
without communicating this allocation to any other device or entity. The wireless
microphone may also communicate the frequency to another device receiving signal
such as audio data from the wireless microphone. Such an allocation cannot be
detected by accessing a database because the allocation is not registered
anywhere. Thus, such an allocation has to be detected by sensing the use of this
device. Sensing may be performed by the base station and/or by the wireless
terminal
After gathering the information the communication channel is established at the
communication channel frequency in the second frequency band. This establishing
step considers the gathered information and establishes the communication channel
at a communication channel frequency, where no interferences or any other
disturbance with the at ieast one other device and/or servers is expected.
According to embodiments of the invention at least one second portion of the
second frequency band is used for terrestrial digital video and/or audio broadcast.
This does not mean that the at least one second portion of the second frequency
band is used exclusively for digital video and/or audio broadcast but may also be
used for wireless telecommunication or other wireless communication. Some
portions of the second frequency band may for example be used for digital video
and/or audio broadcast in a first area, while the same portion may be used for
wireless telecommunication in a second area, wherein the first and the second area
do not overlap. This corresponds to the definition of white space frequencies. White
space frequencies are in general frequencies which may be used by a certain
service of device such as a DVB-T sender but are locally not used by this service or
device.
According to embodiments of the invention the step of gathering information
comprises sensing the use of frequencies in the second frequency band by the base
station and/or the wireless terminal and/or reading the use of frequencies in the
second frequency band from a database.
According to embodiments of the Invention the control channel data comprises the
bandwidth to be used by the communication channel. This is advantageous for
limiting the used bandwidth and avoiding interferences or any other disturbances of
communication performed by at least one other device and/or servers in the second
frequency band.
According to embodiments of the invention the method comprises further the steps
of modifying the communication channel and/or dismantling the communication
channel, instructions to modify or to dismantle the communication channel is
transmitted from the base station to the wireless terminal via the control channel.
Modifying and/or dismantling the communication channel may be advantageous,
when the used communication channel frequency causes problems to other devices
and/or at least one other device is switched on, which causes interferences
and/or other disturbances to the communication of the wireless terminal.
According to embodiments of the invention the method comprises further the steps
of determining a velocity of the wireless terminal, determining if the velocity is below
a velocity threshold, and establishing the communication channel, only if the velocity
is below the velocity threshold. These three method steps are advantageous
because communication is only outsourced to the second frequency band, if the
velocity of the wireless terminal is below a velocity threshold. This is advantageous
because fast-moving wireless terminals may easily disturb communication of
devices using frequencies in the second frequency band without registering
anywhere, When only the traffic of slow-moving wireless terminals, which means
that their velocity is below the velocity threshold, is outsourced to the second
frequency band, fast changes in the electromagnetic environment of the wireless
terminal can be avoided.
According to embodiments of the invention the method further comprises the
following steps, when the at least one portion of the second frequency band is
allocated to the at least one other device and/or service, and when the wireless
terminal is being moved with a velocity along a trajectory:
determining the velocity Of the wireless terminal;
predicting the trajectory of the wireless terminal;
calculating a first time value using the velocity and the trajectory, the first time value
being indicative of a time period, after which the communication channel is
established. The velocity and the trajectory of the wireless terminal may for example
be determined by common GSM, UMTS or LTE techniques or by a GPS method, if
the wireless terminal has a GPS receiver. Embodiments of the invention are
advantageous because the first time value, which is calculated based on the velocity
and the trajectory may indicate a time point, at which it is advantageous to establish
the communication channel in the second frequency band. Thus, from the time point
on when the communication channel may be established no time is lost for any
further communication and the communication channel is established on time. The
time point is determined according to the gathered information, the velocity and the
trajectory of the wireless terminal. The time point is chosen such that ho
communication of any other device in the second frequency band is disturbed by
the communication channel. This method is advantageous, if the wireless terminal is
expected to be located in a region, where the at least one portion of the second
frequency band Is not allocated to any device and/or service after the time period. At
this time point, the communication channel is established at the communication
channel frequency.
According to embodiments of the invention the method comprises further the step of
calculating a second time value by using the velocity and the trajectory, the second
time value being indicative of the maximum time period between establishing the
communication channel and dismantling the communication channel. In other
words, the second time value is the period during which the communication channel
is established. For example for a fast-moving wireless terminal communication via
the communication channel is only possible for a certain amount of seconds or
minutes, before communication of another device in the second frequency band is
disturbed by the telecommunication of the wireless terminal because the wireless
terminal moves towards the other device.
According to embodiments of the invention, the communication channel is
established, only if the maximum time period between establishing the
communication channel and dismantling the communication channel is above a time
threshold. This is advantageous for avoiding offloading or outsourcing connections
for only short times. It is desirable by the operator to rather outsource connections of
wireless terminals, which are expected to be outsourced for a comparable long time
period.
According to embodiments of the invention authentication data, authorization data,
location data, and routing area data are transmitted via the control channel from the
wireless terminal to the base station. Authentication data and authorization data is
transmitted to the base station for identifying the wireless terminal. The
authentication and authorization data is for example stored on the subscriber
identity module (SIM) of the wireless terminal. The authentication and authorization
data identifies the wireless terminal, the user of the wireless terminal, and/or the
servers to be used by the user/the wireless terminal. Authentication and
authorization is performed according to standards of GSM, UMTS and/or LTE
networks. Location data is advantageously transmitted to the base station for letting
the base station gather information concerning the use of the at least one portion of
the second frequency band in the area of the wireless terminal The base station
has to know where the wireless terminal is located for gathering information of used
frequencies in this area. Routing area data is transmitted from the wireless terminal
to the base station via the control channel for updating information in the base
station for internet connections of the wireless terminal.
According to embodiments of the invention the wireless terminal comprises
spectrum sensing means. The spectrum sensing means are adapted to sense, if the
first portion of the second frequency band is used by the at least one other device
and/or servers. The sensing means detect the use of the first portion of the second
frequency band from primary users such as DVB-T senders for example or wireless
microphones being located near the wireless terminal. A near location to the
wireless terminal is characterized herein as the fact that the wireless terminal is
located in the coverage area of the wireless microphone. Instead of a wireless
microphone or a DVB-T sender any other device using frequencies in the second
frequency band may be sensed by the sensing means of the wireless terminal. This
is mandatory for not disturbing communication of any other device in the second
frequency band. Also other mobile communication may be sensed by the wireless
terminal through the sensing means. For example other wireless terminals being
near to the wireless terminal may already communicate on the second frequency
band. This is also sensed by the sensing means. This is advantageous for avoiding
interferences and to find a suitable communication channel frequency without
causing interferences or any other disturbance with other communicating devices.
The wireless terminal further comprises transmitting means, the transmitting means
being adapted to transmit a signal to the base station. The signal is indicative of the
first portion of the second frequency band being used by the at least one other
device. This step is advantageous for transmitting the information gathered by the
sensing means to the base station. The base station then decides which portion of
the second frequency band is used for the communication channel frequency. The
base station avoids the use of a frequency being already used by another device.
nother aspect the invention relates to a base station apparatus comprising
- means for establishing a control channel at a control channel f re
quency in a first frequency band between a wireless terminal and a
base station of the wireless communication network, the first fre¬
quency band being exclusively used for wireless telecommunication;
- means for gathering information about a second frequency band, the
information being indicative of at least a first portion of the second fre¬
quency band not being allocated to at least one other device and/or
service;
- means for determining if the traffic load in the first frequency band is
above a thresh old;
- means for transmitting control channel data via the control channel
from the base station to the wireless terminal, if the traffic load in the
first frequency band is above the threshold, wherein the control chan¬
nel data comprises a communication channel frequency in the second
frequency band of a communication channel;
- means for establishing a communication channel at the communica¬
tion channel frequency between the wireless terminal and the base
station, if the traffic load in the first frequency band is above the
threshold.
In yet another aspect the invention relates to a computer-readable storage me¬
dium containing instructions that when executed by a base station apparaius ac¬
cording to claim 8 cause the base station apparatus to perform a method of
communicating in a wireless teiecommunicaiion network, the method compris
ing:
- establishing a control channel at a control channel frequency in a first
frequency band between a wireless terminal and a base station of the
wireless communication network, the first frequency band being exclu¬
sively used for wireless telecommunication;
- gathering information about a second frequency band, the information
being indicative of at least a first portion of the second frequency band
not being allocated to at least one other device and/or service;
- determining i f the traffic load in the first frequency band is above a
threshold;
- transmitting control channel data via the control channel from the base
station to the wireless terminal, if the traffic load in the first frequency
band is above the threshold, wherein the control channel data com¬
prises a communication channel frequency in the second frequency
band of a communication channel;
- establishing a communication channel at the communication channel
frequency between the wireless terminal and the base station, if the
traffic load in the first frequency band is above the threshold.
Brief description of the drawings
in the following preferred embodiments of the invention will be described, by way of
example only and with reference to the drawings in which:
Figure 1 is a schematic view of a frequency spectrum and the use of part of
the frequency spectrum for control and for communication issues;
Figure 2 is a block diagram of a base station apparatus being operable to
perform a method according to embodiments of the invention; and
Figure 3 is a flow diagram of a method of communicating in a wireless
telecommunication network.
Figure 4 Is a schematic view of a cell of a wireless telecommunication
network
Detailed description
Like numbered elements in these Figs are either identical elements or perform the
same function, Elements which have been discussed previously will not necessanly
be discussed in later Figs if the function is identical.
Fig, 1 is a schematic view of a frequency spectrum reaching from 400-1 000 MHz.
The frequency spectrum comprises a plurality of frequency bands. A first frequency
band 102 may for example reach from 790-970 MHz. A second frequency band 100
is located for example between 470 and 790 MHz and is called white space
frequency band 100. In different parts of the world the first and the second
frequency band may comprise different frequencies and/or frequency ranges. The
first frequency band 102 consists of portions, which are referred to as LTE uplink
104, LTE downlink 108, QSM uplink 106, and GSM downlink 108. The first
frequency band 102 may also comprise portions for communication according to
the UMTS or CDMA standard. The first frequency band 102 comprises licensed
frequencies to control the usage of the white space frequencies in the second
frequency band 100 for offloading parts of the operator's traffic. Usually, the traffic in
a wireless telecommunjGation network is transmitted in the licensed frequency
range, which corresponds to the first frequency band 102. When traffic load in a ceil
of the wireless telecommunicatson network exceeds a ceil load threshold if is
advantageous to source out or offload parts of the traffic into the white space
frequency band, which corresponds to the second frequency band 100, Care has to
be taken not to disturb primary users.. Primary users are herein understood as users
being originally using the white space frequency band 100. This may for example be
DVB-T senders and/or other devices not registering their frequency allocation in a
central network entity, such as wireless microphones information about used and
unused, or in other words allocated and not allocated portions of the white space
frequency band 100 is gathered by the base station 112. The use of frequencies
may also be detected by sensing means of a wireless terminal 114.
The base station 112 controls the communication of the wireless terminal 114. The
base station 112 decides when to source out or offload communication of the
wireless terminal to a communication channel being located in the white space
frequency band 100. The control channel stays in the licensed frequency band 102.
This is advantageous because by controlling the wireless terminal 114 via the
licensed frequency band 102 no other communication device is disturbed. The base
station sends control channel data via the control channel and communication data
via the communication channel in the white space frequency band 100. Because the
communication channel frequency is sent to the wireless terminal via the
control channel no other communication is disturbed. The base station 112 knows
about the used and unused, or in other words allocated and not allocated
frequencies in the white space frequency band 100. Preferably, communication
channels in the white space frequency band 100 are only established for wireless
terminal 114 below a velocity ihreshofd. If the wireless terminal 114 would be moved
faster than the velocity threshold, interferences with other devices would become
more probable and it may be advantageous to offload the communication of another
not depicted wireless terminal to the white space frequency band 100. The control
channel in the licensed frequency band 102 functions according to the standards of
UMTS, LIE or GSM. Also the communication of the wireless terminal with the base
station 112 via the communication channel in the white space frequency band 100
works according to UMTS, LTE or GSM standards. The control channel does not
disturb or interfere with primary users in the white space frequency band 100,
because the control channel lies in the licensed frequency band 102, where only
wireless telecommunication takes place.
Fig. 2 is a block diagram of a base station 200. The base station 200 comprises
means 202 for estabiishing a control channel at a control channel frequency in a
first frequency band between a wireless terminal and a base station of the wireless
communication network, the first frequency band being exclusively used for wireless
telecommunication. The base station 200 further comprises means 204 for gather¬
ing information about a second frequency band, the information being indicative of
at least a first portion of the second frequency band not being allocated to at least
one other device and/or service. Means 206 are adapted to determine, if the traffic
load in the first frequency band is above a traffic load threshold. Furthermore, the
base station 200 comprises means 208 for transmitting control channel data via the
control channel from the base station to the wireless terminal, if the traffic load in the
first frequency band is above the threshold, wherein the control channel data comprises
a communication channel frequency in the second frequency band of a com¬
munication channel. Means 2 10 are adapted to establish a communication channel
at the communication channel frequency between the wireiess terminal and the
base station, if the traffic load in the first frequency band Is above the threshold.
In operation, the base station 200 establishes a control channel between itself and a
wireless terminal by using means 202. Then, information about the second fre¬
quency band, which is also referred to as the white space frequency band, is gathered
with means 204. The gathered information is used later on by means 2 10 for
establishing a communication channel with the wireless terminal. The communica¬
tion channel is established, only if means 206 have determined, that the traffic load
in the first frequency band Is above the traffic load threshold. This is advantageous
for SQureing out traffic load in a wireless telecommunication cell into the white space
frequency hand without causing interferences or disturbing the communication of
primary users in the white space frequency in any other way. The control channel
lies in the first frequency band, which comprises frequencies licensed for wireless
telecommunication. Thereby, interferences or disturbances caused by the control
channel are avoided.
Fig. 3 is a flow diagram of a method according to embodiments of the invention. In a
first step SI a control channel at a control channel frequency in a first frequency
band between is established. The control channel serves for controlling the connec¬
tion of a wireless terminal to a base station of the wireless communication network.
The control channel lies in the first frequency band, which is used exclusively for
wireless telecommunication. Controlling is performed according to standards of the
wireless telecommunication network, e.g. GSM, UMTS or LTE standards.
In a second step S2 information is gathered about a second frequency band. The
second frequency band is for example a white space frequency band, which could
for example be used for DVB-T and/or wireless microphones or other devices with a
small coverage area. The gathered information is Indicative of at least a first portion
of the second frequency band not being allocated to at least one other device and/or
service such as a wireless microphone and/or DVB-T, It Is again to be noted that the
at least one other device may for example be a DVB-T sender. The frequency of a
wireless microphone may for example be only allocated in the wireless microphone
and the respective receiver.
In a third step S3 it is determined, if the traffic load in the first frequency band is
above a traffic load threshold. After this determination, afourth step 34 is per¬
formed, The fourth step comprises transmitting control channel data via the control
channel from the base station to the wireless terminal, if the traffic load in the first
frequency band is above the traffic load threshold. The control channel data com¬
prises a communication channel frequency of a communication channel. The com¬
munication channel frequency ties in the second frequency band in other words, the
communication channel in the second -frequency band is established, only if the traffie
load in the respective cell is so high that the operator may want to offload or out¬
source some traffic. In this case, an offloading or outsourcing of traffic into the sec¬
ond frequency band is advantageous for reducing traffic in the first frequency band.
In a fifth step S5 a communication channel between the wireless terminal and the
base station is established at the communication channel frequency, if the traffic
load in the first frequency band is above the traffic load threshold.
If is to be noted that the order of these steps Is not necessarily limited to S1-S2-S3-
S4-S5. Any other reasonable order may alternatively be applied to perform a
method according to embodiments of the invention.
Fig. 4 is a schematic view of a cell 402 of a wireless telecommunication network.
Communication in eel! 402 takes place in the first frequency band according to
GSM, UlvlTS or LTE standards. The second frequency band corresponds to white
space frequency band 400. White space frequency band 400 is available anywhere
in cell 402 and also outside cell 402. In regions 404 and 406 at least a portion of the
white space frequency band 400 is allocated to at least one other device and/or ser¬
vice, which may for example be DVB-T transmissions and/or the use of a wireless
microphone.
A wireless terminal is moved along trajectory 408 with a certain velocity. Based on
the trajectory 408 and the velocity, the base station (not depicted) of cell 402 is able
to determine the maximum time period, in which the wireless terminal may use the
at least one portion in the white space frequency band 400. The maximum time
period is the time between the time point, when the wireless terminal exits region
406 at the geographical point 412, and the time point, when the wireless terminal
enters region 404 at the geographical point 410.

C I a ims
A method of communicating in a wireless telecommunication network,
wherein the method comprises the following steps:
- establishing (SI ) a control channel at a control channel frequency in a
first frequency band (102) between a wireless terminal (1 14) and a
base station ( 1 12) of the wireless communication network, the first fre¬
quency band being exclusiveSy used for wireless telecommunication;
- gathering (S2) information about a second frequency band ( 1 00), the
information being indicative of at least a first portion of the second fre¬
quency band not being allocated to at least one other device and/or
service;
~ determining (S3) if the traffic load in the first frequency band is above
a traffic load threshold;
- transmitting (S4) control channel data via the control channel from the
base station to the wireless terminal, if the traffic load in the first fre
quency band is above the traffic load threshold, wherein the control
channel data comprises a communication channel frequency in the
second frequency band of a communication channel;
- establishing (S5) a communication channel at the communication
channel frequency between the wireless terminal and the base station,
if the traffic load in the first frequency band is above the traffic load
threshold.
Method according to claim 1, wherein at least a second portion Of the second
frequency band is used for terrestrial digital video and/or audio broadcast.
Method according to any one of the preceding claims, wherein the step of
gathering informatipn comprises sensing the use of frequencies in the second
frequency band by the base station and/or reading the use of frequencies in
the second frequency band from a database.
4. Method according to any one of the preceding claims, wherein the control
channel data comprises the bandwidth to be used by the communication
channel,
5. Method according to any one of the preceding c!aims, wherein the method
further comprises the steps of
- modifying the communication channel; and/or
- dismantling the communication channel
6, Method according to any one of the preceding claims, wherein the method
further comprises the steps of:
- determining a velocity of the wireless terminal;
- determining if the velocity is below a velocity threshold;
- establishing the communication channel, only if the velocity is below
the velocity threshold.
7, Method according to any one of the claims 1-5, wherein the at least one por¬
tion of the second frequency band is allocated to the at least one other device
and/or service, wherein the wireless terminai is being moved with a velocity
along a trajectory, wherein the method further comprises the steps of:
- determining the velocity of the wireless terminal;
- predicting the trajectory of the wireless terminal ;
- calculating a first time value using the velocity and the trajectory, the
first time value being indicative of a time period, after which the wire¬
less terminal is expected to be located in a region, where the at least
one portion of the second frequency band is not allocated to any de¬
vice and/or service;
- establishing the communication channel at the communication channel
frequency.
& Method according to claim 7, wherein the method further comprises the step
of:
~ calculating a second time value by using the velocity and the predicted
trajectory, the second time value being indicative of the maximum time
period between establishing the communication channel and disman¬
tling the communication channel
9. Method according to claim 8 , wherein the communication channel is estab¬
lished, only if the maximum time period between ..establishing the communica¬
tion channel and dismantling the communication channel is above a time
threshold.
10. Method according to any one of the preceding claims, wherein authentication
data, authorization data, location data and routing area data are transmitted
via the control channel from the wireless terminal to the base station.
11.Method according to any one of the preceding claims, wherein the wireless
terminal comprises
- spectrum sensing means, the spectrum sensing means being adapted
to sense, if the first portion of the second frequency band is used by
the at least one other device and/or service; and
- transmitting means, the transmitting means being adapted to transmit
a signal to the base station, the signal being indicative of the first por¬
tion of the second frequency band being used by the at least one other
device,
12. A base station apparatus (200) comprising
- means (202) for establishing a control channel at a control channel
frequency in a first frequency band between a wireless terminal and a
base station of the wireless communication network, the first fre¬
quency band being exclusively used for wireless telecommunication;
- means (204) for gathering information about a second frequency band,
the information being indicative of at least a first portion of the second
- frequency band not being allocated to at least one other device and/or
service;
- means (206) for determin ing if the traffic load in the first frequency
band is above a traffic load threshold;
- means (208) for transmitting control channel data via the control chan
nel from the base station to the wireless terminal, if the traffic load in
the first frequency band is above the threshold, wherein the control
channel data comprises a communication channel frequency in the
second frequency band of a communication channel;
- means (21 0) for establishing a communication channel at the commu¬
nication channel frequency between the wireless terminal and the
base station, if the traffic load in the first frequency band is above the
threshold.
13.A computer-readable storage medium containing instructions that when exe¬
cuted by a base station apparatus according to claim 12 cause the base sta¬
tion apparatus to perform a method of communicating in a wireless telecom¬
munication network, the method comprising:
- establishing a control channel at a control channel frequency in a first
frequency band between a wireless terminal and a base station of the
wireless communication network, the first frequency band being exclu¬
sively used for wireless telecommunication;
- gathering information about a second frequency band, the information
being indicative of at feast a first portion of the second frequency band
not being allocated to at least one other device and/or service;
- determining if the traffic load in the first frequency band is above a traf¬
fic load threshold;
- transmitting control channel data via the control channel from the base
station to the wireless terminal, if the traffic load in the first frequency
band is above the threshold, wherein the control channel data com¬
prises a communication channel frequency in the second frequency
band of a communication channel;
- establishing a communication channel at the communication channel
frequency between the wireless terminal and the base station, if the
traffic load in the first frequency band is above the threshofd.