uplink radio freq uency sig nals at the master u t may improve an overa ll
system performa ce of the radio commu nication system because of an
increased SINR(SINR = Signal to nterference-pl us-Noise Ratio) in
comparison to receiving the uplink radio frequency signals via a single
anten na array and recovering the data from the single received upl ink
radio frequency signa ls.
SUMMARY
The way of processi ng upl ink radio frequency sig nals received by a radio
comm unication systems effects bandwidths of transmissio n links between
network nodes of the radio com muni cation system, effects time delays for
data handl ing of uplink data and effects processi ng capacities at the
network nodes of the radio com muni cation system .
It is an object of the invention to reduce CAPEX (CAPEX = CAPita l
Expen diture) such as i nstal lation costs and OPEX (OPEX = Operational
expenditure) such as energy consumption for operati ng a radio
comm unication system .
The object s achieved by a method for receivi ng uplink radio frequency
signals in a rad io com munication system, wherei n the radio com munication
system comprises at least one anten na system for a reception of the uplin k
radio frequency signals, a first slave uni connected to the at least one
antenna system, and a master unit control ling the f rst slave unit, and
wherei n the method comprises the steps of receivi ng at the at least one
anten na system the upli nk radio freq uency signa ls, verifyi ng, whether a
characteristic pa rameter of the received upli nk radio freq uency sig nals
fulfi lls a predefined criterion and control ling a forwa rdi ng of the received
upli nk radio frequency signa ls to the master unit dependi ng o a fulfi llment
of the predefi ned criterion. The object is further achieved by a master unit
for use in a rad io com munication system , by a first slave unit for use in a
radio communication system, by a radio network controller comprising the
master unit, by a base station comprising the master unit and/or the first
slave unit and by a remote radio head comprising the first slave unit.
The master unit may be for example a master unit of a cooperative cluster
of several antenna systems performing a multipoint reception such as
applied in Co P or the master unit may be located in a base station
controlling for example a single slave unit located for example i a remote
radio head or in an active antenna array.
The method offers a first benefit of requiring less transmission capacity on
transmission links between the master unit and the one or several slave
units. This means, that the radio communication system may be planned
and installed with smaller transmission capacity on transmission links
between the master unit and the one or several slave units than without the
invention and thereby reduces the installation costs.
The method offers a second benefit of reacting to short-term changes such
as fast fading on a transmission channel from a mobile station to the at
least o e antenna system and avoiding a transmission of radio frequency
signals from the one or several slave units of a so-called cooperation cluster
to the master unit of the cooperation cluster, which may not improve
significantly a reception quality of the radio frequency signals o r which may
arrive too late in case of time-sensitive services such as interactive gaming
o r VoIP (VoI = Voice over Internet Protocol). Thereby, transmission power
for forwarding the received uplink radio frequency signals to the master unit
and processing power for processing the forwarded received uplink radio
frequency signals can be reduced. Most benefit can be realized in particular
for data-intensive services such as video conferencing or video upload
requested by a user of the mobile station.
The verifying step may be done for an overall signal received at two or
more antenna elements of the at least one antenna system or the verifying
step may be done separately for each antenna element of the a least one
antenna system receiving the uplink radio frequency signals such as in a
case of an active antenna array.
The predefined criterion may depend on one or several of the following
parameters such as a transport format of the uplink radio frequency signals
on a radio link from the mobile station to the at least one antenna system,
and/or unused transmission resources on a connection from the first slave
unit to the master unit, and/or required transmission resources on the
connection from the first slave unit to the master unit for the uplink radio
frequency signals, and/or quality of a channel estimation algorithm
performed at the first slave unit, and/or a location of a mobile station
transmitting the uplink radio frequency signals within a coverage area of
the at least one antenna system, and/or velocity of the mobile station
transmitting the uplink radio frequency signals.
In a preferred embodiment, the method further comprises the steps of
determining at the master unit the predefined criterion for the characteristic
parameter, transmitting from the master unit to the first slave unit
information of the predefined criterion, and verifying at the first slave unit,
whether the characteristic parameter fulfills the predefined criterion.
The preferred embodiment provides a benefit of centrally controlling wilhin
the cooperation cluster, which radio frequency signals should be
superimposed a the master unit and therefore should be transmitted from
the one or several slave units to the master unit.
In a further preferred embodiment, the determining step is based on a
prediction of the predefined criterion before the upli n k radio frequency
signals are forwarded to the master unit or before the uplink radio
frequency signals are received from a second one of the at least one
antenna system assigned to the master unit. The further preferred
embodiment provides a benefit of configuring the predefined criterion at
the one or several slave units in advance before any radio frequency signals
of the mobile station are transmitted from the mobile station to the
cooperation cluster. The prediction of the predefined criterion may based
for example on long-term measurements providing indications for average
path losses between a specific location of the mobile station and the two or
more antenna system of the cooperation cluster and affected for example
by long-term impacts such as reflections incurred by obstacles on a
transmission path of the uplink radio frequency signals between the mobile
station and the antenna arrays of the cooperation cluster. The obstacles
may be for buildings, tunnels, hills, etc.
In an even further preferred embodiment, a second one of the at least one
antenna system is connected to a network node comprising the master unit
and the method further comprises the steps of determining at the master
unit an offset value of the predefined criterion, receiving at the master unit
the uplink radio frequency signals via the second one of the at least one
antenna system, determining at the master unit a value of the characteristic
parameter of the uplink radio frequency signals received via the second one
of the at least one antenna system, and the predefined criterion is
determined based on the value of the characteristic parameter and based
o n the predefined offset value. This allows determining the predefined
criterion more suitable to a current condition of the multipoint reception by
taking into account a current reception quality of the first one of the uplink
radio frequency signals which have been directly received at the master unit
via the second one of the at least one antenna system connected to the
network node comprising the master unit and without a reception of uplink
radio frequency signals at the master unit forwarded from the slave unit.
Thereby, in a best case, the reception quality of the first one of the uplink
radio frequency signals is already sufficient to recover information elements
of the received uplink radio frequency signals such as user data bits of the
service error-free and a forwarding of further uplink radio frequency signals
from the one or several slave units to the master unit is not required.
In a further alternative embodiment, a second one of the at least o e
antenna system s connected to a network node comprising the master unit
and the method further comprises the steps of determining at the master
unit and at the first slave unit an offset value of the predefined criterion,
receiving at the master unit the uplink radio frequency signals via the
second one of the at least one antenna system, determining at the master
unit a value of the characteristic parameter of the uplink radio frequency
signals received via the second one of the at least one antenna system,
transmitting the value of the characteristic parameter from the master unit
to the first slave unit, and determining at the first slave unit the predefined
criterion based on the value of the characteristic parameter and based on
the predefined offset value. The further alternative embodiment is similar to
the above mentioned embodiment with the difference, that not the
predefined criterion is transmitted fro the master unit to the first slave unit
but the value of the characteristic parameter determined at the master unit
and that the first slave unit determines the predefined criterion based on the
offset value configured at the first slave unit and based on the value of the
characteristic parameter determined at the master unit and received from
the master unit.
In a first alternative embodiment, the characteristic parameter is a service
type of the received uplink radio frequency signals, the predefined criterion
is a predefined delay class of the received uplink radio frequency signals
and the predefined delay class depends on a transmission time delay of the
uplink frequency signals from a mobile station via the first slave unit to the
master unit. The first alternative embodiment allows blocking for a delay
sensitive service such as a video conference those uplink radio frequency
signals at the slave units, which would arrive too late at the master unit for
a superposition with other uplink radio frequency signals directly received at
the master unit or at other slave units with a smaller transmission time
delay. A transmission time from the mobile station via the slave unit to the
master unit may depend on a length of a transmission path from the slave
unit to the master unit or on a remaining processing capacity at the slave
unit for processing and forwarding the received uplink radio frequency
signals.
In a second alternative embodiment, the characteristic parameter is a
reception quality of the received uplink radio frequency signals and the
predefined criterion is a predefined reception signal quality. Preferably, the
predefined reception signal quality is a signaI-to- interferenee and noise
ratio threshold value, a signal-to-interference ratio threshold value, or a
signal-to-noise ratio threshold value.
According to a further preferred embodiment, the method further comprises
the steps of determining at the first slave unit the reception quality of the
received uplink radio frequency signals, transmitting information of the
reception quality from the first slave unit to the master unit, verifying at the
master unit, whether reception of the uplink radio frequency signals via
the first slave unit is required for recovering information transmitted by the
uplink radio frequency signals, and transmitting from the master unit to the
first slave unit, if the reception of the uplink radio frequency signals via the
first slave unit is required, a requesl for t ra nsmitting the received uplink
radio frequency signals from the first slave unit to the master unit. The
further preferred embodiment may be applied for services with less
stringent time delay requirements, because at a first sub-step a
measurement result of the reception quality of the received uplink radio
frequency signals is transmitted from the first slave unit to the master unit
and not until a second sub-step the received uplink radio frequency signals
itself are transmitted from the first slave unit to the master unit, if the master
unit has requested such a transmission. Thereby, the master unit is able to
control for each received uplink radio frequency signals, whether the
received uplink radio frequency signals should be transmitted from the first
slave unit to the master unit and should be used for a superposition at the
master unit or the received uplink radio frequency signals should be
discarded at the first slave unit. In addition, this allows distributing a
measurement process and a decision making process for the received
uplink radio frequency signals across the first slave unit and the master unit.
Further advantageous features of the invention are defined and a e
described in the following detailed description of the invention.
BRIEF DESCRIPTION O F THE FIGURES
The embodiments of the invention will become apparent in the following
detailed description and will be illustrated by accompanying figures given
by way of non-limiting illustrations.
Figure 1 shows a block diagram of a radio communication network
according to a first embodiment of the invention.
Figure 2 shows a block diagram of a radio communication network
according to a second embodiment of the invention.
Figure 3 shows a flow diagram of a method n accordance to the first or the
second embodiment of the invention.
Figure 4 shows a flow diagram of a method in accordance to a further
embodiment of the invention.

etc. and may describe equipment that provides wireless connectivity via one
o r more radio links to one or more mobile stations.
Further base stations, further connections between the base stations, and
connections between the base stations and network nodes of the core
network are not shown for simplification.
The first base station RAN 1-BSl comprises for example a master unit BSMU,
a first remote radio head RRH 1 with active elements such as a power
amplifier (RRH = remote radio head), a first transmission path BSl -LI
between the first base station RANI -BSl and the first RRH RRH , and a first
antenna system BSl -AS located next to the first base station RA -BS
without active elements and directly connected to the first base station
RANI -BS. Alternatively, the first base station RANI -BSl comprises more
than one RRH and/or more than one antenna system directly connected to
the first base station RANI -BS.
The first antenna system BSl -AS may comprise for example two antenna
elements. Alternatively the first antenna system BSl -AS may comprise more
than two antenna elements such as four antenna elements.
The first transmission path BSl -L may be for example based o n the CPRI
standard (CPRI = Common Public Radio Interface).
The first RRH RRH comprises a first slave unit RRH-SU and a second
antenna system RRH -AS connected to the first slave unit RRH-SU. The
second antenna system RR -AS may comprise for example two antenna
elements and may be a passive antenna array o r an active antenna array.
Alternatively the second antenna system RRH 1-AS may comprise more than
two antenna elements such as four antenna elements.
The first antenna system BSl -AS provides wireless coverage for a first radio
cell BS-Cell-1 and the second antenna system RRH 1-AS provides wireless
coverage for a second radio cell RRH-Cell-2.

The term "radio cell" may be considered synonymous to and/or referred to
as cell, radio sector, sector etc.
The second base station RANI -BS2 comprises a second slave unit BS-SU
and a third antenna system BS2-AS connected to the second slave unit B5-
SU. The third antenna system BS2-AS may comprise two antenna elements
and provides wireless coverage for a third radio cell BS-Cell-3. In further
alternatives, the second base station RANI -BS2 may comprise more than
one antenna system and the third antenna system BS2-AS may comprise
more than two antenna elements such as four antenna elements.
The first slave unit RRH-SU and the second slave unit BS-SU are controlled
by the master unit BS-MU.
The first radio cell BS-Ce , the second radio cell RRH-Cell-2 and the third
radio cell RRH-Cell-3 are configured to be parts of a cooperative cluster
CC.
The term "cooperative cluster" may be considered synonymous to and/or
referred to as cooperative set, cooperation set, CoMP cluster, cluster etc.
and may describe two or more antenna elements of a radio communication
system that cooperate for a joint reception of uplink radio frequency signals
from one or more mobile stations.
Preferably, the antenna arrays respectively the radio cells belonging to the
cooperative cluster CC may be selected based o n distributed selfconfiguration
algorithms executed at the base stations RAN -BS , RAN -
BS2 of the radio communication system RCS1 . The self-configuration
algorithms may be based for example on long term measurements for
pathlosses between mobile stations located within the coverage areas of the
radio cells BS-Cell-l , RRH-Cell-2 and RRH-Cell-3 and the antenna systems
BS1 -AS, RRH -AS and BS2-AS o f the radio communication system RCS1 .
In an alternative, the cooperative cluster CC may be configured by a n O&M
network node (O&M — Operation and Maintenance) of the radio
communication system RCS1 (not shown in Figure 1 for simplification).
A mobile station RAN I -MS may be located within an overall coverage area
of the cooperative cluster CC.
In a n uplink direction from the mobile station RAN 1-MS to the radio access
network RANI , a l the radio cells or a subset of the radio cells BS-Cell-1 ,
RRH-Cell-2, RRH-Cell-3 of the cooperative cluster CC may receive in a
multipoint reception mode via a n uplink MIMO transmission (MIMO =
multiple input multiple output) o r an uplink SIMO transmission (SIMO =
single input multiple output) uplink radio frequency signals from the mobile
station RANI -MS.
The term "mobile station" may be considered synonymous to, and may
hereafter be occasionally referred to, as a mobile unit, mobile user, access
terminal, user equipment, subscriber, user, remote station etc. The mobile
station RA I -MS may be for example a cellular telephone, a portable
computer, a pocket computer, a hand-held computer, a personal digital
assistant or a car-mounted mobile device.
If for example the first slave unit RRH-SU receives uplink radio frequency
signals from the mobile station RAN -MS via the corresponding second
antenna system RRH1 -AS, the received uplink radio frequency signals are
forwarded from the first RRH RRH1 to the first base station RAN 1-BS1 via
the first transmission path BS -LI , if a characteristic parameter of the uplink
radio frequency signals received at the first RRH RRH 1 fulfils a predefined
criterion.
In a same way, the second base station RAN1 -BS2 forwards received uplink
radio frequency signals to the first base station RANI -BS1 , if the
characteristic parameter of the uplink radio frequency signals received at
the second base station RANI -BS2 fulfils the predefined criterion.
More detailed descriptions of methods of the present invention applied
within the radio communication system RCS1 are given with respect to
Figure 3 to Figure 5.
Figure 2 shows a radio communication system RCS2 comprising a radio
access network AN2 according to a second embodiment of the invention.
The core network of the radio communication system RCS2 and
connections of the radio communication system RCS2 to further radio
communication systems, to the Internet or to fixed line communications
systems are not shown for simplification.
The radio communication system RCS2 may be for example a 3GPP UMTS
radio communication network using OFDM (OFDM = Orthogonal
Frequency Division Multiplexing). In a further alternative, the radio
communication system RCS2 may for example a 3GPP HSUPA radio
communication network (HSUPA —high speed uplink packet access).
The radio access network RA 2 comprises exemplarily a radio network
controller RNC, a first base station RAN2-BS1 , a first transmission path
RNC-L1 between the first base station RAN2-BS1 and the radio network
controller RNC, a second base station RAN2-BS2 and a second
transmission path RNC-L2 between the second base station RAN2-BS2 and
the radio network controller RNC.
The first transmission path RNC-L1 and the second transmission path RNCL2
may be for example an lub interface such as used in 3GPP UMTS.
The term "radio network controller" may be considered synonymous to
and/or referred to as a base station controller, RNC, BSC etc. and may
describe equipment that controls one or more base stations of a radio
access network.
Further radio network controllers and further base stations of the radio
access network RAN are not shown for simplification.
The radio network controller RNC comprises a master unit RNC-MU for
controlling slave units BS-SU1 , BS-5U2 of the first and the second base
station RAN2-BS1 , RAN2-BS2.
The first base station RAN2-BS1 comprises a first slave unit BS-SU1 and
a first antenna system RAN2-BS1 -AS connected to the first slave unit BSSU1
. The first antenna system RAN2-BS1 -AS may comprise for example one
antenna element for providing wireless coverage for a first radio cell BSCell-
1 . Alternatively, the first antenna system RAN2-BS1 -AS may comprise
more than one antenna element and the first antenna system RAN2-BS1 -AS
may be a passive antenna array or an active antenna array.
I a further alternative, the first base station RAN2-BS1 may comprise more
than one antenna system for providing wireless coverage to more than one
radio cell.
The second base station RAN2-BS2 comprises a second slave unit BS-SU2
and a second antenna system RAN2-BS2-AS connected to the second slave
unit BS-SU2. The second antenna system RAN2-BS2-AS may comprise for
example one antenna element for providing wireless coverage for a second
radio cell BS-Cell-2. Alternatively, the second antenna system RAN2-BS2-AS
may comprise more than one antenna element and the second antenna
system RAN2-BS2-AS may be a passive antenna array or an active antenna
array.
In a further alternative, the second base station RAN2-BS2 may comprise
more than one antenna system for providing wireless coverage to more
than one radio cell.
A mobile station RAN2-MS may be in an overlap region of the first radio
cell BS-Cell-1 and the second radio cell BS-Cell-2 and may be in a socalled
soft handover state such as applied in a UMTS FDD transmission
mode (FDD = Frequency Division Duplex). This means, that the mobile
station RAN2-MS simultaneously communicates with the first a d the
second base station RAN2-B51 , RAN2-B52 a d the first and the second
base station RAN2-BS1 , RAN2-BS2 transmit on a downlink dedicated
channel same information to the mobile station RAN2-MS. n the uplink
direction from the mobile station RAN2-MS to the radio access network
RAN2, the first and the second base station RAN2-B51 , RAN2-BS2 receive
uplink radio frequency signals from the mobile station RAN2-MS.
If the first slave unit BS-SU1 receives uplink radio frequency signals from the
mobile station RAN2-MS via the corresponding first antenna system RAN2-
BSl -AS, the received uplink radio frequency signals e forwarded from the
first slave unit BS-SU1 to the master unit RNC-MU via the first transmission
path RNC-L1 , if a characteristic parameter of the received uplink radio
frequency signals at the first slave unit BS-SU1 fulfils a predefined criterion.
In a same way, the second slave unit BS-SU2 forwards received uplink radio
frequency signals to the master unit RNC-MU, if the characteristic
parameter of the received uplink radio frequency signals fulfils the
predefined criterion at the second slave unit BS-SU2.
Alternatively, if the first and the second radio cell BS-Cell- 1, BS-Cell-2 may
belong to a same base station, the same base station may comprise a
master unit and the first and the second slave unit BS-SU1 , BS-SU2 and the
mobile station RAN2-MS may be in a so-called softer handover state, a
similar internal predefined criterion may be applied for the characteristic
parameter of received uplink radio frequency signals o forwa rdi ng the
received uplink radio frequency signals from the first and the second slave
unit BS-SU l , BS-SU2 to the master unit.
If both, the uplink radio frequency signals received at the first antenna
system RAN2-BS1 -AS and the uplink radio frequency signals received at the
second antenna system RAN2-BS2-AS do not fulfil the predefined criterion,
the radio network controller RNC does not receive any uplink radio
frequency signals within a predefined time frame. In such a case, the radio
network controller RNC may resolve such a situation by temporally lowering
the predefined criterion for both, the first and the second slave unit BS-SUl ,
BS-SU2 for example for a short time interval such as one or several TTIs (TTI
= transmit time interval) as applied in 3GPP LTE.
A more detailed description of the method applied within the radio
communication system RCS2 is given with respect to Figure 3 to Figure 5 .
Referring to Figure 3 a flow diagram of a method MET1 in accordance to
the first and the second embodiments of the invention is shown. The
number of the steps for performing the method MET1 is not critical, and as
can be understood by those skilled in the art, that the number of the steps
and the order of the steps may vary without departing from the scope of the
invention.
The flow diagram is shown between a first network node NN1 comprising
the master unit MU, a second network node NN2 comprising the slave unit
SU, and a mobile station MS. According to the first embodiment of Figure
1, the first network node NN1 ay be the first base station RA N -BS , the
master MU may be the master unit BS-MU, the second network node NN2
may be one of the first RRH RRH1 or the second base station RAN1 -BS2, the
slave unit SU may be one of the slave units RRH-SU, BS-SU and the mobile
station MS may be the mobile station RAN 1-MS. According to the second
embodiment of Figure 2, the first network node NN 1 may be the radio
network controller RNC, the master U may be the master unit RNC-MU,
the second network node NN2 may be one of the first base station RAN2-
BS1 or the second base station RAN2-BS2, the slave unit SU may be one of
the slave units BS-SU1 , BS-SU2 and the mobile station MS may be the
mobile station RAN2-MS.
In a first step M l / , the predefined criterion of the characteristic parameter
may be determined at the master unit MU. In a n alternative, the predefined
criterion may be determined at the O&M network node of the radio
communication system RCSl , RCS2 and may be transmitted from the O&M
network node to the master unit MU.
Preferably, the characteristic parameter may be a reception quality of the
received uplink radio frequency signals and the predefined criterion may be
a predefined reception signal quality.
The predefined reception signal quality may be for example an SINR
threshold value SINR _ threshold given for example in dB and the reception
quality of the received uplink radio frequency signals may a slave SINR
measurement value SINR _ lave _ easure to be measured at a network
node comprising the slave unit SU.
In a first alternative, the predefined reception signal quality may be an SIR
threshold value (SIR = signal-to-interference ratio; also known as the
carrier-to-interference ratio) SI _ threshold given for example in dB and
the reception quality of the received uplink radio frequency signals may a
slave SIR measurement value SIR_slave_ measure to be measured at the
network node comprising the slave unit SU.
In a second alternative, the predefined reception signal quality may be a n
a n SNR threshold value (SNR = signal-to-noise ratio) SN _threshold given
for example in dB and the reception quality of the received uplink radio

unit SU in comparison to the case with a velocity in a range of a velocity of
a car driving through a city.
Alternatively, the characteristic parameter may be a service type of the radio
frequency signals to be received and the predefined criterion may be a
predefined delay class. Each service type such as background service (e.g.
file upload, email transmission), VoIP service or gaming service may be
assigned a delay class, which is one of a group of delay classes. The group
of delay classes may comprise for example a first delay class FAST for a
transmission time delay from the mobile station MS via one of the slave
units to the master unit MU below a first predefined value, a second delay
class AVERAGE for the transmission time delay between the first predefined
value and a second predefined value above the first predefined value and a
third delay class SLOW for the transmission time delay above the second
predefined value. The background service may be assigned for example the
third delay class SLOW, the VoIP service may be assigned for example the
second delay class MIDDLE and the gaming service may be assigned for
example the first delay class FAST (see Table ) .
Table 1
The predefining algorithm for predefining at the master unit MU for the
slave unit SU one delay class out of the group of delay classes may use as
an input parameter the transmission time delay of the uplink radio
frequency signals from the mobile station MS v a the slave unit SU to the
master unit MU.
Exemplorily according to Figure 1, the master unit MU may predefine the
first delay class FAST for the first slave unit RRH-SU because an average
transmission time delay from the mobile station MS via the first slave unit
RRH-SU to the master unit BS-MU is below the first predefined value and the
third delay class SLOW to the second slave unit BS-SU because a average
transmission time delay from the mobile station MSvia the second slave
unit BS-SU to the master unit BS-MU is above the second predefined value
see Table 2). The average transmission time delay may depend on a
distance between the network node comprising the slave unit and the
network node comprising the master unit and may depend on a processing
load at the network node comprising the slave unit for processing and
forwarding the received uplink radio frequency signals to the network node
comprising the master unit.
Table 2
Alternatively, the predefining algorithm may apply in addition one o r
several of the input parameters as given above according to the predefining
algorithm for the predefined reception signal quality.
In a next step Ml /2, the master unit MU transmits to the slave unit SU
information INFO-PC related to the predefined criterion. Exemplorily, the
master unit MU may transmit the SINR threshold value SINR _ threshold to
the slave unit SU.
In a further step Ml/3, the slave unit SU receives the information INFO-PC.
The steps M l / 1 to Ml / 3 may be performed before any communication
between the radio access network RAN and the mobile station RAN 1-MS
o r between the radio access network RAN2 and the mobile station RAN2-
MS takes place. This means, that the criterion may be predefined by a
prediction using the predefining algorithm as described bove before any
uplink radio frequency signals are received via the slave unit SU o r are
irectl received at the master unit MU via an antenna system assigned and
directly connected to the network node such as the base station RANI -BS1
comprising the master unit BS-MU.
I a next step l /A, if the master unit MU has received a mobile-originated
service request from the mobile station MS or a mobile-terminated service
request for the mobiles station MS such as an incoming voice call (not
shown in Figure 3 for simplification), the master unit MU may decide about
uplink radio resources for a transmission of radio frequency signals from
the mobile station MS to the cooperative cluster CC. The uplink radio
resources may be for example a resource unit (two PRB: physical resource
block in 3GPP LTE) of 1 ms length of time and a group of 12 adjacent
frequency subcarriers such as applied in 3GPP LTE. f frequency hopping is
applied, a frequency switching to a further group of 2 adjacent frequency
subcarriers is applied after 0.5 ms of the 1 ms length of time (after half
length of time of the resource unit).
In a further step Ml /5, the master unit MU transmit one uplink grant UG1
to the mobile station MS. An uplink grant comprises information such as a
code rate for coding the uplink radio frequency signals at the mobile station
MS, a type of modulation for modulating the uplink radio frequency signals
at the mobile station MS and a set of frequency subcarriers to be used by
the mobile station MS for the transmission of the uplink radio frequency
signals.
In a next step Ml /6, the mobile station MS receives the uplink grant UGl
from the master unit MU.
in a further step Ml /7, which may be applied preferably n parallel to the
step Ml/5, the master unit MU transmits scheduling information SCHEDINFO-
MS to the slave unit SU. The scheduling information SCHED-INFOMS
may comprise the same information as comprised in the uplink grant
UGl and may further comprise information about CAZAC (constant
amplitude zero auto-correlation) sequence or so-called Zadoff-Chu
sequence to be applied by the mobile station MS. The CAZAC sequence is
applied to uplink pilots to be transmitted simultaneously with the uplink
data within the uplink radio frequency signals from the mobile station MS to
the cooperative cluster CC. The scheduling information SCHED-INFO-MS
allows the slave unit SU to identify, n which frequency range the uplink
frequency signals can be detected and which CAZAC sequence is applied to
the uplink pilots. The scheduling information SCHED-INFO-MS may further
comprise information of the assigned delay class depending on the service
type of the service running at the mobile station MS.
In a next step Ml /8, the slave unit SU receives the scheduling information
SCHED-INFO-MS from the master unit MU.
In an alternative, the information elements of the scheduling information
SCHED-INFO-MS may be added to the one or several uplink grants UGl ,
UG2, UG3 and the one or several uplink grants UGl , UG2, UG3 re not
only forwarded by the slave unit SU to the mobile station MS but also
processed at the slave unit SU in such a way, that the information elements
for identifying which received radio frequency signal belongs o which
mobile station are extracted and stored at the slave unit SU.
I □ further alternative, the information INFO-PC related to the predefined
criterion and the scheduling information SCHED-INFO-MS may be
transmitted in a single message from the master unit MU to the slave unit
SU.
In a next step M l /9, the mobile station MS transmits uplink radio frequency
signals RFS to the second network node NN2 comprising the slave unit SU,
The uplink radio frequency signals comprise a data unit of several
information bits, C C bits (CRC = cyclic redundancy check) and parity bits.
In a further step Ml/1 0, the second network node NN2 comprising the
slave unit SU receives the uplink radio frequency signals RFS via an
assigned and connected antenna system (e.g. the first RRH RRH1 receives
the uplink radio frequency signals from the mobile station RANI -MS via the
second antenna system RRH 1-AS; see Figure ) .
In a next step M l / I , a receiver of the second network node NN2
comprising the slave unit SU identifies the uplink radio frequency signals
RFS by using the scheduling information SCHED-INFO-MS and may store
the received uplink radio frequency signals RFS in a memory such as a
memory element of an FPGA (FPGA = Field-programmable Gate Array).
In a further step Ml/1 2, which may be performed preferably in parallel to
the step Ml / 1, a value of the characteristic parameter of the received
uplink radio frequency signals RFS such as the slave SINR measurement
value SINR _ lave measure may be determined, if the characteristic
parameter is a SINR. The slave SINR measurement value
SINR _ slave _ measure may be determined for example by a common
channel estimation algorithm of a receiver of the first RRH RRH such as an
MMSE receiver (MMSE = minimum mean squared error).

depending o n a fulfilment of the predefined criterion verified by the step
M l / 13 .
If the predefined criterion is fulfilled, the received uplink radio frequency
signals RFS are forwarded to the network node comprising the master unit
ML) and if the predefined criterion is not fulfilled, the received uplink radio
frequency signals RFS are discarded a the network node comprising the
slave unit SU. Thereby, the stored uplink radio frequency signals RFS may
be queried from the memory.
The radio frequency signals RFS may be forwarded in a common form of
l/Q samples in a frequency domain after a n FFT (FFT = Fast Fourier
Transformation) per antenna element. Only l/Q samples of those antenna
elements will be forwarded, which fulfil the predefined criterion.
In an alternative, the radio frequency signals RFS may be forwarded in a
common form of soft bits per antenna system comprising one o r several
antenna elements after a pre-processing of received uplink radio frequency
signals at a network node comprising the antenna system for generating
the soft bits.
The forwarded l/Q samples or the forwarded soft bits may comprise an
information header with information identifying the l/Q samples like a
range of PRB numbers, a frame and a subframe number.
In a next step M l / l 5, the second network NN2 comprising the master unit
MU receives the forwarded uplink radio frequency signals RFS.
In a further step Ml/1 6, an MMSE receiver of the second network node
NN2 may perform a common superposition such as an MMSE combining
of the forwarded uplink radio frequency signals RFS with one o r several
further uplink radio frequency signals obtained directly from an antenna
system assigned to the master unit MU and/or obtained from a further slave
unit to recover the information bits of the data unit belonging to a specific
mobile station service.
Figure 4 shows schematically a block diagram of a method MET2 for
multipoint reception according to a further embodiment of the invention.
The elements in Figure 4 that correspond to elements of Figure 3 have been
designated by s e reference numerals.
In addition fo the steps l / 2 to M / 1 of the method MET! , the method
MET2 may further comprises steps M2/1 to M2/7.
In a further step M2/1 , an offset value of the predefined criterion may be
predefined at the master unit MU and preferably also at the slave unit SU.
The offset value may be individually determined for each slave unit o r may
be equally determined for each slave unit controlled by the master unit MU.
In further alternatives, the offset value may be only predefined and
configured at the master unit MU or the offset value may be only
predefined at the master unit MU and may be transmitted from the master
unit MU to the slave unit SU or the offset value may be predefined at the
O&M network node and may be transmitted from the O&M network node
to the master unit MU and preferably also to the slave unit SU.
The offset value may be for example an SINK value SINK window in dB, if
the predefined criterion is the predefined reception signal quality provided
by the 5INR threshold value SINK threshold .
The two dots in Figure 4 represent the steps M / 5 to M l /8, which c not
shown in Figure 4 for simplification.
In the steps M l /9, M l / 10 first uplink radio frequency signals RFS1 are
transmitted from the mobile station MS to the slave unit SU and are
received at the salve unit SU.
In a next step M2/2, the second network node NN2 receives the first uplink
radio frequency signals RFSl via a directly assigned and collocated antenna
system (e.g. the master unit BS-MU receives the first uplink radio frequency
signals RFSl from the mobile station RANI -MS via the first antenna system
BS1 -AS, which belongs to the base station RAN -BS1 ; see Figure 1).
a further step M2/3, the master unit MU preferably may store the
received first uplink radio frequency signals RFS in a memory such as a
memory element of an FPGA.
In a next step M2/4, a value of the characteristic parameter of the received
first uplink radio frequency signals RFSl such as a master SINR
measurement value SINR _ master _ measure may be determined by the first
network node NN1 , if the characteristic parameter is an SINR. This means,
that the value of the characteristic parameter is determined without any
superposition of the first uplink radio frequency signals at the master unit
MU by using only the uplink radio frequency signals RFSl directly received
at the first network ode N . The value of the characteristic parameter of
the received first uplink ra o frequency signals RFSl depends o n a distance
between the mobile station RAN -MS and the first antenna system BS1 -AS
(see Figure ) and depends on a transmission characteristic of the first
uplink radio frequency signals RFSl . The transmission characteristic is for
example impacted by a number of antenna elements of a n antenna system
of the mobile station MS and thereby impacted^ whether the mobile station
MS is able to transmit the first uplink radio frequency signals RFSl in a
directed or in an undirected way.
The master SINR measurement value SINR _ aste _ measure may be
obtained for example by a common channel estimation algorithm of a
receiver of the first network node N (see Figure ) such as a n MMSE
receiver.
In a further optional step M2/5, the master unit MU may determine the
predefined criterion such a s the predefined reception signal quality
provided by the SINR threshold value SINR threshold by using for example
following equation:
SINR _ threshold = SINR _ master _ measure- SINR _ window [ )
In the step M l 7 , the master unit MU transmits to the slave unit SU either
the information INFO-PC of the predefined criterion such as the SINR
threshold value SINR _threshold or information INFO-VAL-CP of the value
of the characteristic parameter of the received first uplink radio frequency
signals RFS1 such as the master SINR measurement value
SINR _ master _ measure .
In a further step M2/6, if the slave unit SU has received the information
INFO-VAL-CP of the value of the characteristic parameter of the received
first uplink radio frequency signals RFS1 , the slave unit SU determines the
predefined criterion based on the value of the characteristic parameter of
the received first uplink radio frequency signals RFS1 and based o n the
offset value configured at the slave unit SU by using for example a n
equation identical to the equation ( 1) .
Then a further processing of the first uplink radio frequency signals RFS1 is
performed similar to the method MET1 by the steps M l / 13 to M l / 1 .
If by repeating the step M l / 9 second uplink radio frequency signals RFS2
are transmitted from the mobile station MS to the network nodes NNl ,
NN2 of the slave unit SU and the master u it M U the method MET2 may
be continued according to a first alternative by receiving and storing the
second uplink radio frequency signals RFS2 at the second network node
NN2 comprising the slave unit SU by repeating the st s M l / 10 and
M l / and by receiving and storing the second uplink radio frequency
signals RF52 at the first network node NNl comprising the master unit U
by repeating the steps M2/2 and M2/3. Then according to the first
alternative, the slave unit SU may process the second received uplink radio
frequency signals RFS2 with a same predefined criterion as applied for the
first received uplink radio frequency signals RFS1 and the master unit MU
may not determine a second predefined criterion to be applied for the
second received uplink radio frequency signals RF52 as shown in Figure 4 .
According to a second alternative embodiment (not shown in Figure 4), the
steps M l / 6 to M 1/7 and M2/2 t o M2/6 may be repeated for the second
received uplink radio frequency signals RFS2. This means contrary to the
first alternative embodiment, that the predefined criterion is not reused for
processing the second received uplink radio frequency signals RFS2 and
that the master unit MU determines a second value of the characteristic
parameter of the received second uplink radio frequency signals RFS2 and
that he second value of the characteristic parameter of the received second
uplink radio frequency signals RFS2 o r a second predefined criterion based
on the second value of the characteristic parameter of the received second
uplink radio frequency signals RFS2 is transmitted from the master unit MU
to the slave unit SU for verifying at the slave unit SU in the repeated step
M l / 3 , whether a second value of the characteristic parameter determined
at the slave unit SU and obtained from the second uplink radio frequency
signals RFS received at the slave unit SU fulfil the second predefined
criterion. The second alternative embodiment allows continuously adapting
the predefined criterion to a fast-varying channel quality of the radio link
between the mobile station RAN 1-MS and the cooperation cluster CC (see
Figure 1),
The three dots in Figure 4 represent the steps M l / to M l / 13 , which are
not shown n Figure 4 for simplification.
Figure 5 shows schematically a block diagram o f a method MET3 for
multipoint reception according t o an even further embodiment of the
invention. The elements in Figure 5 that correspond to elements of Figure 3
and Figure 4 have been designated by same reference numerals.
In addition to the steps M l / 1, M l / 4 to M l / 12, and M l / to M l / of the
method MET1 and the steps M2/2 and M2/3 of the method MET2 he
method MET3 may further comprises steps M3/1 to M3/5.
The two dots in Figure 5 represent the steps Ml / 5 to M l /8, which are not
shown in Figure 5 for simplification.
In a further step M3/1 after the step M l / 12, the slave unit SU transmits to
the master unit MU information INFO-RC of the reception quality such as
the value of the characteristic parameter of the uplink radio frequency
signals RFS received at the slave unit SU. The information INFO-RC of the
reception quality may be for example the slave SINR measurement value
SINR _ slave_ measure , if the characteristic parameter is a n SINR.
In a next step M3/2, the master unit M U receives the information INFO-RC
of the reception quality.
In a further step M3/3, the master unit MU verifies, whether a reception of
the first uplink radio frequency signals via the slave unit SU is required for
recovering the information (e.g. the data block) transmitted by the f st
uplink radio frequency signals RFS1 .
Such verification may be done for example by following sub-steps;
If a reception quality of the first uplink radio frequency signals directly
received at the master unit MU and not received via one o the slave units is
already sufficient for recovering error-free the information transmitted by
the first uplink radio frequency signals RFS1 , no superposition with further
first uplink radio frequency signals received via one o f the slave units is
required.
If a reception quality of the first uplink radio frequency signals directly
received at the master unit MU and not received via one of the slave units is
not sufficient for recovering error-free the information transmitted by the
first uplink radio frequency signals RFS1 , the master unit MU may perform a
ranking of the reception quality of the first uplink radio frequency signals
RFS1 at the slave units and the master unit MU may only select one or a
subset of the slave units with a highest reception quality of the ranking. The
selection of one o r several slave units may depend o n a missing reception
power to be required for recovering error-free the information transmitted
by the first uplink radio frequency signals RFS1 .
In the following it is assumed, that the reception quality of Ihe slave unit SU
has be selected and identified by the master unit MU as one of the highest
reception qualities of all reception qualities received from the slave units
controlled by the master unit MU.
In a next step M3/4, the master unit MU transmits to the slave unit SU a
request REQ for ttansmitiing the first uplink radio frequency signals RFS l
received and stored at the slave unit SU to the master unit MU.
In a further step M3/5, the slave unit SU receives the request REQ from the
master unit MU.
The method MET3 is continued with the steps Ml/1 4 to M l / 6 .
All steps of the method MET3 may be repeated for every uplink radio
frequency signal transmitted from the mobile station MS and received at the
master unit MU and the slave unit SU such as shown in Figure 5 for the
second uplink radio frequency signals RFS2.
The three dots in Figure 5 shown between the steps M2/2 and M l / 15
according to the master unit MU represent the steps M2/3, M3/2, 3/ 3,
and M3/4, which are repeated for processing the second received uplink
radio frequency signals RFS2 and are not shown n Figure 5 for
simplification.
The three dots in Figure 5 shown between the steps M l / I 0 and M l / 14
according to the slave unit SU represent the steps Ml / 11, M / 1 , which
are repeated for processing the second received uplink radio frequency
signals RFS2 and are not shown in Figure 5 for simplification.
With respect to all three exemplarily methods MET! , MET2, and MET3 the
predefined criterion is selected dependent on an overall reception quality of
the uplink radio frequency signals received from the mobile station MS
and/or dependent on a service type of the service running at the mobile
station MS regarding a transmission time delay for the uplink radio
frequency signals. This means, that the predefined criterion may specifically
selected for each mobile station transmitting the radio frequency signals
and for each slave unit receiving the radio frequency signals.
The methods MET1 , MET2, and MET3 may be used for a multipoint
reception using several antenna systems o r may be used for a single-point
reception using a single antenna system. In both cases, if the characteristic
parameter of the received uplink radio frequency signals does not fulfil the
predefined criterion at all antenna systems for the multipoint reception or at
the single antenna system for the single-point reception, the master unit will
not receive ny uplink radio frequency signals for recovering a data unit
contained in the uplink radio frequency signals and the radio
communication system may request a retransmission for the data unit by
transmitting further uplink radio frequency signals containing the data unit.
Figure 6 shows functional block diagram of a master unit MU. The master
unit MU may be part for example of a baseband processing block of a
base station o r of a base station interface of a radio network controller. The
master unit MU may comprise a determining block MU-DET-B for
determining the predefined criterion for the characteristic parameter of the
uplink radio frequency signals, for determining preferably the offset value
of the predefined criterion, and for determining preferably the value of the
characteristic parameter of the uplink radio frequency signals. The master
unit M U may further comprise an interface MU-IF for external
communication for providing information INFO-PC related to the
predefined criterion such a s the predefined criterion itself or the offset value
of the predefined criterion, preferably the scheduling information SCHEDINFO-
MS, preferably the information INFO-VAL-CP of the value of the
characteristic parameter of the received first uplink radio frequency signals,
and preferably the request REQ to the slave unit SU . The interface MU-IF is
further used for receiving the information INFO-RC of the reception quality
of the uplink radio frequency signals RFS received at the slave unit SU such
a s the slave SINR measurement value SINR _ lave measure for a passive
antenna array of the slave unit SU o r a first slave SINR measurement value
SINR\ _ slave _ measure for a first antenna element of a n active antenna
array of the slave unit SU and a second slave SINR measurement value
SINR2 _ lave _ measure for a second antenna element of the active antenna
array of the slave unit SU.
The master unit M U may further comprise a verification block MU-VER-B for
verifying, whether the reception of the first uplink radio frequency signals
via the slave unit SU is required for recovering the information (e.g. the
data block) transmitted by the first uplink radio frequency signals RFS1 . The
master unit MU may further comprise a memory block MU-MEM-B for
storing the predefined criterion related to the slave uni SU and related to
the mobile station MS and preferably related to the service type running at
the mobile station MS, for storing preferably the offset value of the
predefined criterion related to the slave unit SU and related to the mobile
station MS and for storing preferably the uplink radio frequency signals
directly received via an antenna system connected to the network node
comprising the master unit ML).
Figure 7 shows a functional block diagram of a slave unit SU. The slave unit
SU may be part for example of a baseband processing block of a base
station or of a baseband processing block of an RRH with base band
functionalities shifted from the baseband processing block of the base
station to the baseband processing block of the RRH.
The slave unit SU may comprise a verification block SU-VER-B for verifying,
whether the characteristic parameter of the received uplink radio frequency
signals fulfils the predefined criterion and whether the received uplink radio
frequency signals shall be transmitted to the master unit MU o r the received
uplink radio frequency signals shall be discarded.
The slave unit SU may further comprise an interface SU-IF for external
communication for controlling a forwarding of the received uplink radio
frequency signals to the network node comprising the master unit MU by
using a single control command COMMAND to a forwarding unit of the
network node of the slave unit SU for forwarding uplink radio frequency
signals received at a passive antenna system comprising one or several
antenna elements or by using for example a first control command
COMMAND1 for forwarding uplink radio frequency signals received at a
first antenna element of an active antenna array and a second control
command COMMAND2 for forwarding uplink radio frequency signals
received at a second antenna element of an active antenna array and
preferably for providing the information INFO-RC of the reception quality of

, MET2, MET3 when the computer program is executed o n a computer
or processor,
A person of skill in the art would readily recognize that steps of various
above-described methods MET1 , MET2, MET3 ca be performed by
programmed computers. Herein, some embodiments are also intended to
cover program storage devices, e.g., digital data storage media, which are
machine o r computer readable and encode machine-executable or
computer-executable programs of instructions, wherein said instructions
perform some o r all of the steps of said above-described methods. The
program storage devices may be, e.g., digital memories, magnetic storage
media such as magnetic disks and magnetic tapes, hard drives, or optically
readable digital data storage media. The embodiments are also intended
to cover computers programmed to perform said steps of the abovedescribed
methods.
The descri ption and drawings merely illustrate the principles of the
invention. It will thus be appreciated that those skilled in the art will be able
to devise various arrangements that, although not explicitly described o r
shown herein, embody the principles of the invention and are included
within its spirit and scope. Furthermore, al examples recited herein are
principally intended expressly to be only for pedagogical purposes to aid
the reader in understanding the principles of the invention and the concepts
contributed by the inventor(s) to furthering the art, and are to be construed
as being without limitation to such specifically recited examples and
conditions. Moreover, all statements herein reciting principles, aspects, and
embodiments of the invention, as well as specific examples thereof, re
intended to encompass equivalents thereof.
Functional blocks denoted as "means for ..." (performing a certain
function) shall be understood as functional blocks comprising circuitry that
is adapted for performing a certain function, respectively. Hence, a "means
for s.th." may as well be understood as a "means being adapted or suited
for s.th.". A means being adapted for performing a certain function does,
hence, not imply that such means necessarily is performing said function (at
a given time instant).
The functions of the various elements shown in the Figures, including any
functional blocks labeled as "means", "means for receiving", "means for
verifying", "means for determining", "means for transmitting, "means for
performing", "means for scheduling", may be provided through the use of
dedicated hardware, such as " receiver", "a verifier", "a determiner", " a
transmitter" " a performer or a processor", "a scheduler", as well as
hardware capable of executing software in association with appropriate
software. When provided by a processor, the functions may be provided by
a single dedicated processor, by a single shared processor, or by a plurality
of individual processors, some of which may be shared. Moreover, explicit
use of the term "processor" or "controller" should not be construed to refer
exclusively to hardware capable of executing software, and may implicitly
include, without limitation, digital signal processor (DSP) hardware, network
processor, application specific integrated circuit (ASIC), field programmable
gate array (FPGA), read only memory (ROM) for storing software, random
access memory (RAM), and non volatile storage. Other hardware,
conventional and/or custom, may also be included. Similarly, any switches
shown in the Figures are conceptual only. Their function may be carried out
through the operation of program logic, through dedicated logic, through
the interaction of program control and dedicated logic, or even manually,
the particular technique being selectable by the implementer as more
specifically understood from the context.
It should be appreciated by those skilled i the art that any block diagrams
herein represent conceptual views of illustrative circuitry embodying the
principles of the invention. Similarly, it will be appreciated that any flow
charts, flow diagrams, state transition diagrams, pseudo code, and the like
represent various processes which may be substantially represented in
computer readable medium and so executed by a computer or processor,
whether or not such computer or processor is explicitly shown.
CLAIMS
. A method (MET1 , ET2, MET3) for receiving uplink radio frequency
signals (RFS, RFS1 , RFS2) in a radio communication system (RCS1 ,
RCS2), said radio communication system (RCS1 , RCS2) comprises at
least two antenna systems (BSl -AS, BS2-AS, RRH1 -AS, RAN2-BS1 -AS,
RAN2-BS2-AS) of a cooperative cluster (CC) for a multipoint reception of
said uplink radio frequency signals (RFS, RFS1 , RFS2), a first slave unit
(SU, RRH-SU, BS-SU1 , BS-SU2, BS-SU) assigned to a first one of said at
least two antenna systems (BSl -AS, BS2-AS, RRH1 -AS, RAN2-BS1 -AS,
RAN2-BS2-AS), and a master unit (Ml), BS-MU, RNC-MU) controlling
said first slave unit (SU, RRH-SU, BS-SU 1, BS-SU2, BS-SU),
said method (MET1 , MET2, MET3) comprising the step of receiving
(Ml / l 0) at said first one of said at least two antenna systems (BSl -AS,
BS2-AS, RRH1 -AS, RAN2 -BSl -AS, RAN2-BS2-AS) said uplink radio
frequency signals (RFS, RFS1 , RFS2),
characterized in that said method further comprises the steps of:
- verifying (Ml/1 3) at said first slave unit (SU, RRH-SU, BS-SU , BS-SU2,
BS-SU), whether a characteristic parameter of said received uplink radio
frequency signals (RFS, RFS1 , RFS2) fulfills a predefined reception signal
quality, and - controlling (Ml / 1 ) at said first slave unit (SU, RRH-SU,
BS-SU1 , BS-SU2, BS-SU) a forwarding of said received uplink radio
frequency signals (RFS, RFS1 , RFS2) to said master unit (MU, BS-MU,
RNC-MU) depending o n a fulfillment of said predefined reception signal
quality.
2 . Method (MET1 , MET2, MET3) according to claim 1, wherein said
verifying step is performed separately for each antenna element of said
first one of said at least two antenna systems (BSl -AS, BS2-AS, RRH1 -
AS, RAN2-BS1 -AS, RAN2-BS2-AS), if said first one of said a t least two
antenna systems (BSl -AS, BS2-AS, RRHl -AS, RAN2-BS1 -AS, RAN2-BS2-
AS) is a n active antenna array o r wherein said verifying step is
performed once o n y for said first one of said at least two antenna
systems (BS1 -AS, BS2-AS, RRHl -AS, RAN2-BS1 -AS, RAN2-BS2-AS), if
said first one of said a t least two antenna systems (BS1 -AS, BS2-AS,
RRHl -AS, RAN2-BS1 -AS, RAN2-BS2-AS) is a passive antenna system.
3 . Method (MET! , MET2, MET3) according to any of the preceding claims,
wherein said predefined reception signal quality depends o n a t least
one of the following:
- transport format of said uplink radio frequency signals (RFS, RFS1 ,
RFS2) o n a radio link from a mobile station (MS) to said first one of said
a t least two antenna systems (BSl -AS, BS2-AS, RRHl -AS, RAN2-BS1 -AS,
RAN2-BS2-AS),
- unused transmission resources o n a connection from said first slave
unit (SU, RRH-SU, BS-SU1 , BS-SU2, BS-SU) to said master unit (ML), BSMU,
RNC-MU),
- required transmission resources o n said connection from said first
slave unit (SU, RRH-SU, BS-SU1 , BS-SU2, BS-SU) to said master unit
(MU, BS-MU, RNC-MU) for said uplink radio frequency signals,
- quality of a channel estimation algorithm performed a t said first slave
unit (SU, RRH-SU, BS-SU 1, BS-SU2, BS-SU),
- location of a mobile station (RANI -MS) transmitting said uplink radio
frequency signals (RFS, RFS1 , RFS2) within a coverage area of said first
one of said a t least two antenna systems (BS1 -AS, BS2-AS, RRHl -AS,
RAN2-BS1 -AS, RAN2-BS2-AS),
- velocity of the mobile station (RANI -MS) transmitting said uplink radio
frequency signals (RFS, RFS1 , RFS2).
Method (MET! , MET2) according to any of the preceding claims,
wherein said method (MET! , MET2) further comprises the steps of:
- determining (Ml/1 , M2/5) at said master unit (ML), BS-MU, RNC-MU)
said predefined reception signal quality for said characteristic
parameter, and
- transmitting (Ml/2) from said master unit (MU, BS-MU, RNC-MU) to
said at least one first slave unit (SU, RRH-SU, BS-SU1 , BS-SU2, BS-SU)
information of said predefined reception signal quality.
Method (MET! ) according to claim 4 , wherein said determining step
(Ml / I ) is based o n a prediction of said predefined reception signal
quality before said uplink radio frequency signals (RFS) are forwarded to
said master unit (MU, BS-MU, RNC-MU) o r before said uplink radio
frequency signals (RFS) are received from a second one of said at least
two antenna systems (BSl -AS, BS2-AS, RRH1 -AS, RA 2 -BSl -AS, RAN2-
BS2-AS) assigned to said master unit (MU, BS-MU, RNC-MU).
Method (MET2) according to any of the preceding claims 1 to 4 ,
wherein a second one (BSl -AS) of said a t least two antenna systems is
connected to a network node (BSl -AS) comprising said master unit (MU,
BS-MU), wherein said method (MET2) further comprises the steps of:
- predefining (M2/1 ) a t said master unit (MU, BS-MU) a n offset value of
said predefined reception signal quality,
- receiving (M2/2) a t said master unit (MU, BS-MU) said uplink radio
frequency signals (RFS1 ) via said second one (BSl -AS) of said a t least
two antenna systems,
- determining (M2/4) a t said master unit (MU, BS-MU) a value of said
characteristic parameter of said uplink radio frequency signals (RFS! )
received via said second one (BSl -AS) of said a t least two antenna
systems, and
wherein said predefined reception signal quality is determined based on
said value of said characteristic parameter and based on said
predefined offset value.
7. Method (MET1 ) according to any of the preceding claims 1 to 3,
wherein a second one (BS1 -AS) of said at least two antenna systems is
connected to a network node (BS1 -AS) comprising said master unit (MU,
BS-MU), wherein said method (MET! ) further comprises the steps of:
- predefining at said master unit (MU, BS-MU) and at said first slave unit
(SU, RRH-SU, BS-SUl ) an offset value of said predefined reception
signal quality,
- receiving (M2/2) at said master unit (MU, BS-MU) said uplink radio
frequency signals (RFSl ) via said second one (BS1 -AS) of said at least
two antenna systems,
- determining (M2/4) at said master unit (MU, BS-MU) a value of said
characteristic parameter of said uplink radio frequency signals (RFSl )
received via said second one (BS1 -AS) of said at least two antenna
systems,
- transmitting (Ml /2) said value of said characteristic parameter from
said master unit (MU, BS-MU) to said first slave unit (SU, RRH-SU, BSSUl
), and
- determining (M2/6) at said first slave unit (SU, RRH-SU, BS-SUl ) said
predefined reception signal quality based on said value of said
characteristic parameter and based on said predefined offset value.
8 . Method (MET3) according to any of the preceding claims 1 to 3 ,
wherein said method (MET3) further comprises the steps of:
- determining (Ml / 12) said reception quality of said received uplink
radio frequency signals (RFSl , RFS2) at a network node (RRHl , RANI -
BS2, RAN2-BS1 , RAN2-BS2) comprising said first slave unit (SU, RRHSU,
BS-SU1 , BS-SU2, BS-SU),
- transmitting (M3/1 ) information (INFO-RC) of said reception quality to
said master unit (MU, BS-MU, RNC-MU),
- verifying (M3/3) at said master unit (MU, BS-MU, RNC-MU), whether a
further reception of said uplink radio frequency signals (RFSl , RFS2)
from said network node (RRHl , RANI -BS2, RAN2-BS1 , RAN2-BS2) is
required for recovering information transmitted by said uplink radio
frequency signals (RFSl , RFS2), and
- transmitting (M3/4) from said master unit (MU, BS-MU, RNC-MU) to
said first slave unit (SU, RRH-SU, BS-SU 1, BS-SU2, BS-SU) a request
(REG) for forwarding said received uplink radio frequency signals (RFSl ,
RFS2) to said master unit (MU, BS-MU, RNC-MU), if said reception of
said uplink radio frequency signals (RFSl , RFS2) is required.
9 . Method (MET1 , MET2, MET3) according to claim , wherein said
predefined reception signal quality is either of the following:
- a signal-to-interference-and-noise ratio threshold value,
- a signal-to-interference ratio threshold value,
- a signal-to-noise ratio threshold value,
- received signal power threshold value.
10 .Method (MET! ) according to any of the preceding claims 1 to 5 ,
wherein a further characteristic parameter of said received uplink radio
frequency signals (RFS) is a service type of said received uplink radio
frequency signals (RFS), wherein a further predefined criterion is a
predefined delay class of said received uplink radio frequency signals
(RFS) and wherein said predefined delay class depends o n a
transmission time delay of said uplink radio frequency signals (RFS)
from a mobile station (MS) via said first slave unit (SU, RRH-SU, BS-SUl ,
BS-SU2, BS-SU) to said master unit (MU, BS-MU, RNC-MU).
A master unit (MU, BS-MU, RNC-MU) for controlling a slave unit (SU,
RRH-SU, BS-SUl , BS-SU2, BS-SU) in a radio communication system
(RCS1 , RCS2) receiving uplink radio frequency signals (RFS, RFS1 , RFS2)
at a cooperative cluster (CC) of at least two antenna systems (BSl -AS,
BS2-AS, RRH1 -AS, RAN2-BSl -AS, RAN2-BS2-AS),
characterized in that said master unit (MU, BS-MU, RNC-MU)
comprising:
- means (MU-DET-B) for determining a predefined reception signal
quality for a characteristic parameter of said uplink radio frequency
signals (RFS, RFS1 , RFS2), said predefined criterion is applied by said
slave unit (SU, RRH-SU, BS-SUl , BS-SU2, BS-SU) for controlling a
forwarding to said master unit (MU, BS-MU, RNC-MU) of said uplink
radio frequency signals (RFS, RFS1 , RFS2) received at a first one of said
at least two antenna systems (BSl -AS, BS2-AS, RRH1 -AS, RAN2-BS1 -AS,
RAN2-BS2-AS), and
- means (MU-COM-B, MU-IF) for initiating a transmission to said slave
unit (SU, RRH-SU, BS-SUl , BS-SU2, BS-SU) of information (INFO-PC) of
said predefined reception signal quality.
A slave unit (SU, RRH-SU, BS-SUl , BS-SU2, BS-SU) for being controlled
by a master unit (MU, BS-MU, RNC-MU) in a radio communication
system (RCS1 , RCS2) receiving uplink radio frequency signals (RFS,
RFS1 , RFS2) at a cooperative cluster (CC) of at least two antenna
systems (BSl -AS, BS2-AS, RRH1 -AS, RAN2-BSl -AS, RAN2-BS2-AS),
characterized in that said slave unit (SU, RRH-SU, BS-SUl , BS-SU2,
BS-SU) comprising:
- means (SU-VER-B) for verifying, whether a characteristic parameter of
said uplink radio frequency signals (RFS, RFS1 , RFS2) received a t a first
one of said a t least two antenna systems (BSl -AS, BS2-AS, RRH1 -AS,
RAN2-BS1 -AS, RAN2-BS2-AS) fulfills a predefined reception signal
quality, and
- means (SU-CON-B) for controlling a forwarding of said received
uplink radio frequency signals (RFS, RFS1 , RFS2) to said master unit
(MU, BS-MU, RNC-MU) depending o n a fulfillment of said predefined
reception signal quality.
3 .A radio network controller (RNC) comprising a master unit (MU, RNCMU)
according to claim 1.
.A base station (RANI -BS, RAN1 -BS2, RAN2-BS, RAN2-BS2) comprising
a t least one antenna system (BSl -AS, BS2-AS, RA 2 -BSl -AS, RAN2-
BS2-AS) and at least one of the following: a master unit (MU, BS-MU)
according to claim , a slave unit (SU, BS-SU 1, BS-SU2, BS-SU)
according to claim 12 .
.A remote radio head (RRH1 ) comprising a n antenna system (RRH1 -AS)
and a slave unit (RRH-SU) according to claim 2 .