Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/12—Wireless traffic scheduling
  • H04W72/1263—Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows
  • H04W72/1268—Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows of uplink data flows
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/20—Control channels or signalling for resource management
  • H04W72/23—Control channels or signalling for resource management in the downlink direction of a wireless link, i.e. towards a terminal
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L5/00—Arrangements affording multiple use of the transmission path
  • H04L5/14—Two-way operation using the same type of signal, i.e. duplex
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W92/00—Interfaces specially adapted for wireless communication networks
  • H04W92/16—Interfaces between hierarchically similar devices
  • H04W92/20—Interfaces between hierarchically similar devices between access points

Definitions

• the present document describes a method executed in a cell for acquiring Inter-cell scheduling information from a neighboring cell and an arrangement capable of executing the suggested method.
• intra-cell inter-UE User Equipment
• SC-FDMA Single Carrier Frequency Division Multiple Access
• turbo SIC receiver Up Link Successive Interference Cancellation
• PUSCH Physical Uplink Shared Channel
• scheduling information of a neighboring cell can be used for improving the UL reception in three ways, namely 1 ) Acquire interference information of the strongest interfering sources and use UL SIC to mitigate these interferences. 2) Improve the accuracy of a noise and interference covariance matrix estimation for some commonly used receiver, such as e.g. a MMSE-IRC (Minimum Means Square Error Interference Rejection Combining) receiver, or 3) Improving the channel estimation accuracy, and hence improve the total receiver performance.
• MMSE-IRC Minimum Means Square Error Interference Rejection Combining
• Fig. 1 is a simplified illustration of a communications network 100, configured as an LTE network comprising a core network 101 , connected to a plurality of eNBs 102a, 102b, serving a cell 103a, 103b, respectively, allowing UEs, here represented UE 104, connectivity via communication network 100.
• an Operations, Administrations and Maintenance (OAM) 103 is connected to the eNBs.
• Fig. 2 is a simplified illustration of a signaling scheme, which illustrates how scheduling information can be distributed between two adjacent cells, such as the ones described in Fig. 1 , in order to enable a cell 103b, here referred to as the first cell, to acquire scheduling information originating from a neighboring cell 103a, and use this information to reduce the interference caused by the scheduled UL transmission of the neighboring cell 103a. More specifically, a scheduling decision is made for the neighboring cell 103a, as indicated in step 1 : 1a, before the scheduling decision is provided to the first cell 103a via any type of arrangement, interconnecting the respective cells, or more specifically the RBSs (Radio Base Stations) or eNBs serving the respective cells.
• RBSs Radio Base Stations
• eNBs serving the respective cells.
• step 1 :3a the neighboring cell prepares a scheduling command on the basis of the preceding scheduling decision, and in a subsequent step 1 :4a the neighboring cell transmits the scheduling command to a UE 104 served by the neighboring cell 103a, which thereby may receive the scheduling command and use it when transmitting in the UL to the neighboring cell 103a, as well as to other adjacent cells, here represented by the first cell 103b, as indicated in a next step 1 :5a.
• the acquired scheduling decision may be used by the first cell 103b, such that it is taken into consideration when preparing for UL reception at the first cell 103b, as indicated in step 1 : 1b, executed in another step 1 :2b.
• inter-cell communication inter-cell information is exchanged via a vendor specific solution.
• a vendor specific solution Such an implementation could be executed by backboard, by use of inter process communication, or by communication between software blocks/unit, dependent on the implementation.
• a signal can be combined between different cells or different sectors at the same cell.
• High hardware requirements at each RBS site and on the total base band processing capacity will introduce higher processing requirements for the base band processor capacity of the RBS, and hence also higher component and development costs.
• RF Radio Frequency
• an optical fiber or any other solution for providing a high capacity transport channel will be required, and in most cases very costly for the operator.
• a solution supporting different sections in one cell will also require high costs due to the requirement of setting up a high capacity transport channel, e.g. via an optical fiber solution, arranged between the RF system and the RBS, or between different RBS sites.
• a high-capacity, low delay connection is instead provided between each associated RBS and baseband scheduler.
• Such a solution will however result in high deployment requirements at rollout for the operator, due to the fact that the operator will need to provide for geographically separated points connected with e.g. optical fiber.
• An object of the present disclosure is to address the problem mentioned above, and thus to provide an alternative solution to the ones disclosed above.
• an arrangement which is capable of interacting with a first radio base station located in a first cell, where the arrangement comprises a processor, and a memory, where the memory is capable of storing instructions which when executed by the processor causes the processor to control a radio frequency unit associated with the first radio base station to receive scheduling information transmitted from a second radio base station located in a neighboring cell by listening to a downlink control channel; to decode the received scheduling information, and to provide the decoded scheduling information to an uplink receiver and/or an uplink scheduler associated with the first radio base station, thereby enabling for the uplink receiver and/or uplink scheduler to enhance its performance on the basis of the received scheduling information.
• scheduling information may be used more extensively in various network architecture, including networks where corresponding fixed arrangements are very costly to provide.
• the common downlink channel used for listening to scheduling information is the physical downlink control channel, PDCCH.
• the processor may be configured to control the radio frequency unit to listen to the scheduling information via a separate antenna construction dedicated for receiving said scheduling information, where such an antenna construction may comprise a directive antenna.
• the memory may be capable of storing instructions which when executed by the processor causes the processor to control the radio frequency unit such that it listens to the scheduling information when operating as a down link transmitter via a conventional antenna construction.
• the arrangement may be configured to handle Time Division Duplex,TDD, communication, while according to another embodiment, the arrangement may instead be configured to handle Frequency Division Duplex, FDD, communication.
• the memory may be capable of storing instructions which when executed by the processor causes the processor to control the radio frequency unit such that it listens to the scheduling information via the dedicated antenna construction, via a radio frequency path which is arranged separate from a radio frequency path connected to the conventional antenna construction.
• a method is also provided which is executed in a first radio base station located in a first cell for the purpose of acquiring scheduling information associated with a second radio base station located in a neighboring cell.
• the method comprises: listening, via an air interface, to scheduling information transmitted via a downlink control channel from the second radio base station; decoding the received scheduling information, and providing the decoded scheduling information to an uplink receiver and/or uplink scheduler associated with said radio base station, thereby enabling for the uplink receiver and/or uplink scheduler to enhance its performance on the basis of the received scheduling information.
• listening to the scheduling information may be executed when the first radio base station is operating as a down link transmitter via a conventional antenna construction.
• listening to the scheduling information may be executed via the dedicated antenna construction, via a radio frequency path which is separate from a radio frequency path connected to the conventional antenna construction.
• Fig. 1 is an overview of a communications network, according to the prior art.
• Fig. 2 is a signaling scheme illustrating how a first cell can acquire and scheduling decisions taken in a neighboring cell when preparing its UL receiver, according to the prior art.
• Fig. 3 is a signaling scheme illustrating an alternative way of acquiring scheduling information, according to one embodiment.
• Fig. 4 is a flow chart describing a method executed at an arrangement of a cell for acquiring scheduling information from a neighboring cell.
• Fig. 5 is a simplified block scheme describing an arrangement capable of acquiring scheduling information from a neighboring cell, according to another embodiment, where the arrangement comprises a separate dedicated antenna construction.
• Fig. 6 is an RF unit operable according to the prior art.
• Fig. 7 is an RF unit according to a first embodiment for listening to scheduling information transmitted from a neighboring RBS.
• Fig. 8 is an RF unit according to a second embodiment for listening to scheduling information transmitted from a neighboring RBS.
• Fig. 9 is a system architecture according to one embodiment for listening to scheduling information.
• Fig. 10 is an illustration of a link budget for a system architecture according to fig. 9, according to one embodiment.
• an arrangement which enables a cell to listen to scheduling information, or more specifically to scheduling commands, transmitted from a neighboring cell, either by resuing most of the components of an existing antenna system, or via a separate antenna system, typically referred to as a sniffer antenna system, specifically dedicated for listening to scheduling information transmitted from the neighboring cell.
• a sniffer antenna system specifically dedicated for listening to scheduling information transmitted from the neighboring cell.
• the suggested method can be applied without requiring any amendments to the present standardization, and will also be implementable at relatively moderate costs, compared to alternative solutions.
• Fig. 3 is a signaling scheme, illustrating how the suggested method may be executed in a cell, here referred to as a first cell 300, configured to listen to a neighboring cell 301.
• the neighboring cell 301 makes a scheduling decision, and prepares a scheduling command, on the basis of the scheduling decision, as indicated in a subsequent step 3:2a.
• the serving cell transmits the scheduling command, such that it can be received by a respective UE, here represented by UE 302, which may be any type of conventional UE.
• adjacent cells such as the first cell 300
• the first cell 300 will be able to acquire and make use of the scheduling information in the form of scheduling commands, transmitted from the neighboring cell 301 , by listening to such information, as indicated in another step 3: lb.
• the first cell 300 prepares its associated receiver on the basis of the acquired scheduling information.
• the first cell 300 will be able to enhance its receiver performance, by considering the scheduling information during the UL transmission, here expressed with step 3:3b.
• the method mentioned above when executed by an arrangement in a cell adjacent to a neighboring, serving cell, can be described according to the flow chart of fig. 4, which describes successive steps which are typically repeated as long as the method is applied by the cell of an LTE network. Even though the suggested method may be applied only on demand, the method is typically applied by the cell on a permanent basis, such that it is continuously provided with updated scheduling information from the neighboring cell, and such that the neighboring cell can make use of the acquired scheduling information in any way possible for improving its UL receiver performance. As already mentioned above, there are various ways of make use of such information.
• a first step 4: 1 the arrangement of the cell listens to the scheduling information transmitted by the neighboring cell and recognize received scheduling information.
• the arrangement listens to the scheduling information by listens to a downlink control channel, and more specifically the PDCCH (physical downlink control channel).
• the cell initially may blind decode received scheduling information, e.g. by trying different RNTI for CRC check, where if the CRC check is found to be ok, the scheduling information is recognized.
• Such a blind decoding process may be further improved, e.g. by configuring the Operation, Administration and Maintenance (OAM) system to be able to detect, completely or partly, which RNTI that is used by the neighboring cell, thereby limiting the number of RNTIs to be interrogated during the blind decoding.
• OFAM Operation, Administration and Maintenance
• a subsequent step 4:2 the arrangement decodes the received scheduling information, and in a subsequent step 4:3, the eNB prepares the scheduling information, by making it available to its UL receiver.
• the example given above refers to an LTE network, it is to be understood that the described method can be applied on any telecommunications network which can be provided with an additional antenna, as will be described in further detail below.
• FIG. 5 An arrangement which is suitable for applying a method, such as the one suggested above may be arranged according to the simplified block scheme of fig. 5, which illustrates functional entities typically comprised in a RBS or an eNB.
• RBSs are to include also eNBs as possible options. It is to be understood that even though an RBS and a eNB comprise more functional entities, such as e.g. DL (Downlink) receiver and DL scheduler, these are omitted from the figure for simplicity reasons, if not necessary for the understanding of the functionality described herein.
• the arrangement of fig. 5 comprises an additional antenna 502b in addition to the conventional antenna used for conventional communication provided at the RBS/eNB, which has been provided to the RF unit501 of the arrangement 500.
• the RF unit 501 is controllable from a processor 503 in a way which will be further described below.
• the processor 503 is configured to execute the method steps as described in fig. 4 above, by executing instructions stored in a memory 504 and forming a computer program.
• the computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, which may be any entity or device capable of carrying the program.
• Such carriers include e.g. a record medium, computer memory, read-only memory, electrical carrier signal or a telecommunications signal.
• the processor 503 can control reception of scheduling information and provide the received information to the UL receiver 505.
• the UL receiver 505 is connected to an UL scheduler 506, so that, depending on the implementation, the scheduling information can be used by the UL receiver and/or the UL scheduler 506.
• RBS/eNB is configured to perform also the tasks described above, and thus, that arrangement 500 forms part of the RBS/eNB.
• the feature for listening to scheduling information may be implemented as a separate arrangement 507, which is connected to a conventional RBS/eNB.
• the separate arrangement 507 may comprise a separate processor 508, which typically will be dedicated also to other additional tasks, and/or a separate memory 509.
• the additional antenna construction 502b is made higher than the conventional antenna 502a, and/or is directed in a direction which differs from the direction of the conventional antenna, in order to reduce the interference from the conventional antenna construction 502a.
• the dedicated antenna construction 502b may be arranged as an antenna construction which is shielded towards the transmitting antenna of the neighboring cell.
• higher MCL (minimum coupling loss) requirements may be applied between the two antennas by placing the listening antenna perpendicular to the conventional transmitting antenna and/or by increasing the distance between the listening antenna and the conventional antenna. Yet another improvement may be achieved by adding a shield to the listening antenna.
• self interference cancellation may be applied in the receiver when operating as a TDD receiver.
• the RF unit 501 may be configured according to any of a number of alternative embodiments, in order to be able to handle interference caused from the conventional communication handled by the eNB.
• the RF unit 501 of Fig. 5 will now be described below according to two different embodiments with reference to Fig 6 and 7, respectively.
• Fig. 6 is a simplified illustration of an RF unit 600, arranged according to the prior art, suitable for handling TDD (Time Division Duplex) traffic.
• a DAC Digital to Analog Converter
• an Up-converter 602 and a PA Power Amplifier
• 603 are arranged to provide for transmission of time slots via a filter 604 and an antenna construction 605 in the DL
• another branch comprising a LNA (Low Noise Amplifier) 606, a Down converter 607 and a ADC (Analog to Digital Converter) 608 is configured to handle UL time slots received via the antenna construction 605, depending on the state of a high speed switch 609, which is configured to open/close the UL receiver branch, depending on the TDD UL and DL configuration.
• LNA Low Noise Amplifier
• ADC Analog to Digital Converter
• Fig. 7 is another simplified illustration of another RF unit 700, which is suitable for handling TDD, which comprise the same functional units as the embodiment of fig 6 but which has been adapted to be able to also listening to scheduling information from a neighboring cell.
• the embodiment of fig. 7 comprises a further branch comprising a separate filter 701 , a second switch high speed switch 702 and a separate dedicated antenna construction 703, where the mentioned, additional branch is operable when switch 702 is switching on the additional branch, as indicated in fig. 7.
• the latter situation is applied when the FR unit 700 is in UL mode, i.e. when operating in normal TDD UL receiver mode.
• switch 702 is closing its branch, such that the dedicated antenna 703 will be able to listen to scheduling information while the conventional antenna 605 a is used for conventional DL transmission.
• switch 609 may be configured to operate according to a predefined configuration, such that e.g. in a 10 ms interval, the 2 nd , 3 rd , 7 th and 8 th ms are UL time slices when switch 702 is connected, i.e. branch 601-603 is active, while at remaining times, the switch 702 is disconnected and switch 609 is connected, i.e. branch 606-608 is active, listening to scheduling information. This procedure may be repeated every 10 ms, until a new UL/DL configuration is recognized by the processor.
• switch operation information may be sent beforehand, such that e.g. in 1 ms, the RF unit receive information about how to operate switch 602 and 509 in the 1 1 th ms, in the 2 nd ms, RF unit receive information about how to operate the switch in the 12 th ms, and so on.
• Fig. 8 is yet another illustration of an RF unit 800.
• RF unit 800 is configured such that it is capable of handling FDD (Frequency Division Duplex) traffic, where the RF unit 800 comprises a separate RF receiver listening path 801, including a dedicated antenna construction 803, in addition to a conventional UL/DL path 802, including a conventional antenna
• FDD Frequency Division Duplex
• the described arrangement 800 comprises separate hardware which is capable of handling conventional communication and sniffing in parallel to handling conventional UL and DL communication.
• the embodiment of fig. 8 comprises up- and down-converters, DAC, ADCA, PA and LNA which are adapted for handling FDD traffic, accordingly.
• the system architecture comprise a Pico RBS 901, which may be configured according to any of the arrangements described above, including any of the RF configurations also described above.
• a conventional antenna construction 902 is operating as a transmitting antenna, when operating for a transmitter 903, typically forming part of a conventional transceiver, while an arrangement, here referred to as listening arrangement 904, comprising an RF arrangement according to any of the embodiments described above, is configured to listen to scheduling information transmitted from another neighboring RBS, here referred to as macro RBS 905, serving a neighboring cell, via a dedicated antenna 906, here arranged as a directional antenna.
• Fig. 10 is an example illustrating path loss between the different antenna systems of the system configuration illustrated with fig. 9, showing that adequate system performance can be obtained when listening to scheduling information in parallel to performing conventional transceiver functionality, at moderate costs, as long as sufficient isolation between the sniffing and conventional communication is obtained.
• 10: 1 is illustrating the transmitting power of the macro RBS 905 of fig. 9, which present typically equals 40 W, i.e. 46 dbm.
• 10:2 is illustrating the transmitting power of the Pico RBS 901 , which here is 1 W, which equals 30 dbm. While the minimum requirement for a local area RBS, as indicated in chapter 6:2 of 3GPP 36.104, is 24 dbm, a margin of 6 dbm is used in the present example.
• the antenna gain of both the Macro and dedicated Pico antenna 907, 906 is here assumed to be 18 dbi, while the dedicated shielded directive antenna gain is assumed to be 23 dbi.
• the antenna of the Macro cell is much higher than the conventional Pico cell antenna. Due to low transmitting power of the Pico cell, which may typically be 10 times lower than the transmitting power of the Macro cell, also result in lower interference.

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• Computer Networks & Wireless Communication (AREA)
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• 2012
  • 2012-08-01 IN IN333DEN2015 patent/IN2015DN00333A/en unknown
  • 2012-08-01 US US14/417,363 patent/US9585161B2/en not_active Expired - Fee Related
  • 2012-08-01 EP EP12882280.6A patent/EP2880936A4/en not_active Withdrawn
  • 2012-08-01 WO PCT/CN2012/079464 patent/WO2014019155A1/en not_active Ceased

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