HK1178347B - Control information assigning method - Google Patents

Description

Control information assignment method

Technical Field

The present invention relates generally to a method and an arrangement in a radio-access network, and more particularly to transmitting control information in subframes from a network node to an intermediate node.

Background

At its inception, radio technology was designed and used for voice communications. As the consumer electronics industry continues to mature, and the capabilities of processors increase, more devices become available to use wireless transmission of data and more applications become available to operate based on such transmitted data. Of particular interest are the internet and Local Area Networks (LANs). Both of these innovations allow multiple users and multiple devices to communicate and exchange data between different devices and device types. With the advent of these devices and capabilities, users (businesses and homes) find it desirable to transmit data as well as voice from mobile locations.

The infrastructure and networks that support this voice and data transmission have evolved as well. Limited data applications, such as text messaging, are introduced in so-called "2G" systems, such as global system for mobile communications (GSM). Packet data over radio communication systems is becoming more available in GSM with the addition of General Packet Radio Service (GPRS). 3G systems and then even higher bandwidth radio communications (introduced by the Universal Terrestrial Radio Access (UTRA) standard) make internet surfing-like applications more easily accessible to millions of users.

Even as network manufacturers spread (roll out) new network designs, future systems that provide greater data throughput for end-user devices are under discussion and development. For example, the so-called 3GPP Long Term Evolution (LTE) standardization project, also referred to as evolved UTRAN (E-UTRAN) standardization, is used to provide a technical basis for radio communication in the coming decades. Of particular note with respect to LTE systems is that they will provide downlink communications (i.e., the transmission direction from the network to the mobile terminals) using Orthogonal Frequency Division Multiplexing (OFDM) as a transmission format, and will provide uplink communications (i.e., the transmission direction from the mobile terminals to the network) using single carrier frequency division multiple access (SC-FDMA).

It is foreseen that cellular networks such as LTE systems will cover various geographical areas. On the one hand, they are expected to cover urban areas with a high density of buildings with indoor users, while on the other hand, cellular networks should also provide access over large geographical areas in remote rural areas. In both cases, it is challenging to cover the entire service area. A large portion is heavily shadowed from the Base Station (BS) or the link distance is very large, so that the radio propagation characteristics are challenging.

In order to cope with various radio propagation conditions, multi-hop communication has been proposed. The radio link is divided by an intermediate node, e.g. a relay, into two or more hops, each having better propagation conditions than the direct link. This enhances link quality, which results in enhanced cell edge throughput and coverage enhancement.

For LTE-advanced, also referred to as 3GPP release 10, relaying is considered as a tool to improve coverage for e.g. high data rates, group mobility, temporary network deployment, cell edge throughput and/or to provide coverage in new areas. A Relay Node (RN) is wirelessly connected to a radio-access network via a donor cell controlled by a donor enodeb (enb). The RN transmits data to/from User Equipment (UE) controlled by the RN using the same air interface as the eNB, i.e. there is no difference from the UE point of view between the cells controlled by the RN and the eNB.

In LTE, data transmission to/from a UE is under strict control of a scheduler located in the eNB or RN. Control signaling is sent from the scheduler to the UE to inform the UE about the scheduling decision. This control signaling (including one or several Physical Downlink Control Channels (PDCCHs) and other control channels) is transmitted at the beginning of each subframe in LTE, using 1-3OFDM symbols from among the 14 OFDM symbols available in the subframe for normal Cyclic Prefix (CP) and bandwidth greater than 1.8 MHz. For other configurations, these numbers are slightly different. The downlink scheduling assignment indicating to the UE that it should receive data from the eNB or RN is in the same subframe as its data is present. The uplink scheduling grant informing the UE that it should transmit in the uplink occurs several subframes before the actual uplink transmission.

Simultaneous eNB-to-RN and RN-to-UE transmissions on the same frequency resource may not be feasible because the relayed transmitter causes interference to its own receiver unless sufficient isolation of the outgoing and incoming signals is provided by, for example, a specific, well separated and well isolated antenna structure. Similarly, at the relay, it is not possible to receive UE transmissions at the same time as the relay transmits to the eNB. In particular, it may not be feasible for an intermediate node, such as a relay, to receive control information from a network node, such as an eNB, while transmitting the control information in a control signal to a UE controlled by the intermediate node.

Disclosure of Invention

It is therefore a first object of at least some embodiments of the present disclosure to provide a mechanism for enabling transmission of control information from a network node in a radio-access network to an intermediate node, which is an intermediary between the network node and a user equipment in the radio-access network.

A second object according to some embodiments is to enable transmission of control information in a manner that enables efficient use of time-frequency resources in a subframe.

A third object according to some embodiments is to make control information available to an intermediate node in a way that enables the intermediate node to decode data payloads transmitted to the intermediate node in a subframe in a timely manner.

It is a further object of further embodiments of the present disclosure to provide a solution for control signaling between a network node and an intermediate node that is transparent to user equipment.

According to a first embodiment of the present disclosure, at least some of these objects are achieved by a method in a network node for transmitting control information in a subframe from the network node to an intermediate node in a radio-access network. The control information is contained in a time-frequency region transmitted after the control region in the subframe. The control region is transmitted in the beginning (beginning) of the subframe. The control region may be used for control signaling to the user equipment.

The network node transmits first control information in a first part of the time-frequency region and transmits second control information in a second part of the time-frequency region. The time-frequency region is divided such that the second portion is located later than the first portion in the subframe. The second control information may be time-critical (time-critical) less than the first control information.

According to a second embodiment of the present disclosure, at least some of these objects are achieved by a network node comprising a transceiver. The transceiver is adapted to transmit control information in a subframe from the network node to the intermediate node in the radio-access network. The control information is contained in a time-frequency region transmitted after the control region in the subframe. The control region is transmitted in the beginning of the subframe. The control region may be used for control signaling to the user equipment.

The transceiver is adapted to transmit first control information in a first portion of the time-frequency region and second control information in a second portion of the time-frequency region. The time-frequency region is divided such that the second portion is located later than the first portion in the subframe. The second control information may be less time critical than the first control information.

According to a third embodiment of the present disclosure, at least some of these objects are achieved by a method in an intermediate node for receiving control information in a subframe from a network node in a radio-access network. The control information is contained in a time-frequency region located after the control region in the subframe. The control region is located in the beginning of the subframe.

The intermediate node receives first control information in a first portion of the time-frequency region. The intermediate node decodes the first control information. The decoding starts at or after the end of the first part of the time-frequency region. The intermediate node receives and decodes the data payload when the first control information indicates that the subframe contains the data payload to the intermediate node. The intermediate node receives second control information in a second portion of the time-frequency region.

According to a fourth embodiment of the present disclosure, at least some of these objects are achieved by an intermediate node adapted to receive control information in a subframe from a network node in a radio-access network. The control information is contained in a time-frequency region located after the control region in the subframe. The control region is located in the beginning of the subframe. The intermediate node includes a transceiver and a processor.

The transceiver is adapted to receive first control information in a first portion of the time-frequency region and to receive second control information in a second portion of the time-frequency region.

The processor is connected to the transceiver and adapted to control transmission and reception performed by the transceiver. The processor is further adapted to decode the first control information. The processor is adapted to start decoding the first control information at or after the end of the first portion of the time-frequency region.

The transceiver is further adapted to receive a data payload to the intermediate node when the first control information indicates that the subframe contains the data payload, and the processor is further adapted to decode the data payload.

In some examples, the first and second control information may be transmitted during a silent period (silent period) when a user equipment connected to the intermediate node does not expect any transmission from the intermediate node. In one example, the muting period follows the control signaling portion in the MBSFN subframe.

The first control information may contain downlink-related information and the second control information may contain uplink-related information. In some examples, the downlink-related information may be a scheduling assignment related to data transmission from the network node to the intermediate node. The uplink related information may be, for example, a scheduling grant related to data transmission from the intermediate node to the network node.

The first object of the present disclosure is achieved by transmitting control information directed to an intermediate node in a time-frequency region, which is transmitted after a control region, or in other words is located in time after the control region, which is transmitted in the beginning of a subframe, because the control information is transmitted at an opportunity (occasion) when the intermediate node is able to receive the control information.

The second and third objects of the present disclosure are achieved by transmitting a portion of the time-critical control information in a first portion of the time-frequency region and transmitting a portion of the more time-critical control information in a second portion of the time-frequency region. The second object is achieved in that the use of time-frequency resources is more efficient than in some alternative solutions, in that the span of the time-frequency region used for transmitting control information can be made narrower in the frequency domain when the time-frequency region spans substantially up to the end of a subframe, whereby fewer resource blocks are affected by the transmission of control information to the intermediate node. The third object is achieved in that the intermediate node is able to receive and act on time critical information as soon as possible without waiting until the end of the subframe.

By transmitting control information during the silent period, at which the user equipments connected to the intermediate node do not expect any transmission from the intermediate node, the further object is achieved in that the user equipments do not need to change their behavior, as they have been configured to ignore any information transmitted during the silent period.

An advantage of the present disclosure is that it introduces control signaling to a node that is an intermediate node between a network node and a user equipment, while the increase in latency (latency) in the decoding of data transmissions to the intermediate node is kept at a lower level than in some alternative solutions.

Another advantage is that no further channels need to be defined in order to utilize the time-frequency resources located after the time-frequency region in the subframe, i.e. in the time domain, as is the case for some alternative solutions.

A further advantage of some embodiments of the present disclosure is that legacy (legacy) user equipment can still function as desired.

Some embodiments described herein are particularly advantageous for use in systems where an intermediate node receives transmissions from a network node on the same frequency resources as the intermediate node uses for transmissions to its user equipment, especially when the subframe structure is time aligned in a cell controlled by the network node and in a cell controlled by the intermediate node.

Drawings

Fig. 1 is a schematic diagram illustrating a scenario in a radio-access network.

Fig. 2A is a diagram of an example of a subframe structure.

Fig. 2B is a diagram of another example of a subframe structure.

Fig. 3 is an illustration of a subframe structure in accordance with at least some embodiments of the present invention.

Fig. 4 is a diagram of a subframe structure according to an embodiment of the present invention.

Fig. 5 is a combined flow chart and signaling scheme illustrating an embodiment of the present invention.

FIG. 6 is a flow diagram illustrating a method according to an embodiment of the invention.

Fig. 7A is a flow diagram illustrating another method according to another embodiment of the invention.

Fig. 7B is a flow chart illustrating further steps of a method according to another embodiment of the invention.

FIG. 8 is a block diagram illustrating an apparatus according to some embodiments of the invention.

Detailed Description

The following description of exemplary embodiments of the invention refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Although terminology from 3GPP release 10 has been used in this disclosure and specific examples are provided in the context of LTE systems, the invention is not limited in its application to LTE systems, but can be used in any system where, for example, relays or other intermediate nodes between network nodes and user equipment are employed. For example, other wireless systems, including Wideband Code Division Multiple Access (WCDMA), worldwide interoperability for microwave access (WiMax), Ultra Mobile Broadband (UMB), and global system for mobile communications (GSM) systems, may also benefit from utilizing the concepts covered within this disclosure.

According to at least some embodiments of the present disclosure, a solution is provided for transmission of control information from a network node in a radio-access network to a node acting as an intermediate node between the network node and a user equipment. The intermediate node is wirelessly connected to the radio-access network via a cell controlled by the network node. The user equipment is wirelessly connected to the radio-access network via a cell controlled by an intermediate node. Other user equipment may be wirelessly connected to the radio-access network via a cell controlled by the network node. The transmissions between the nodes and the user equipment are performed in subframes. To avoid overlapping in time with the control signaling to the user equipment, which occurs in the control region in the beginning of the subframe, the control information to the intermediate node may be transmitted in a time-frequency region that occurs later in the subframe (i.e., at a time after the transmission of the control region).

The inventors have realized that one part of the control information (e.g. downlink assignment) may be more time critical since it needs to be acted upon by the intermediate node in the subframe in which it is transmitted, and that another part of the control information (e.g. uplink grant) may be more time critical since it need not be acted upon in the subframe in which it is transmitted, but rather in a later time transmitted subframe. In the embodiments described herein, this characteristic of the control information is used to maintain latency in the decoding of data payloads at the intermediate node at as low a level as possible by transmitting a more time-critical portion of the control information (indicated as first control information) in a first portion of the time-frequency region in the subframe, which occurs earlier in time than a second portion of the time-frequency region. The above-mentioned characteristics of the control information further enable an efficient use of time-frequency resources in the subframe, since a less time-critical part of the control information (indicated as second control information) can be transmitted in the second part of the time-frequency region, since this part of the control information does not need to be available to intermediate nodes as soon as possible in the subframe. The solutions of embodiments of the present disclosure are thus further efficient, as they enable a simpler overall structure of the subframe, wherein no further channels need to be defined in order to exploit the time-frequency resources available in the subframe.

To provide some context for a more detailed discussion of the embodiments described herein, consider a first exemplary radio communication system shown in fig. 1. Therein, the radio-access network 120 is configured to communicate with the core network 110 within the radio communication system. Since the example in fig. 1 is provided in terms of LTE, the network nodes transmitting and receiving over the air interface are referred to as enodebs, several of which are shown therein as enodebs 100.

In the context of the air interface, each eNodeB 100 is responsible for transmitting signals to one or more cells 102 and receiving signals from one or more cells 102. According to an exemplary embodiment, each eNodeB 100 includes multiple antennas, e.g., 2, 4 or more transmit antennas, and potentially multiple receive antennas, e.g., 2, 4 or more receive antennas, and handles functions including, but not limited to, encoding, decoding, modulation, demodulation, interleaving, deinterleaving, etc. (with respect to the physical layer of such signals). Note that as used herein, the phrase "transmit antenna" is specifically meant to include and generally refers to physical antennas, virtual antennas, and antenna ports. However, the applicability of embodiments of the present disclosure is not dependent on the number of transmit and receive antennas. In addition, these embodiments may also be applied in an environment where a network node, such as eNodeB 100, and/or an intermediate node, such as relay 103, has only one transmit antenna and/or one receive antenna. The eNodeB 100 is also responsible for a number of higher functions associated with handling communications in the system, including, for example, scheduling users, handover decisions, and the like. According to an exemplary embodiment, a UE104 operating in a cell 102R as shown in fig. 1 will transmit and/or receive signals via a Relay Node (RN)103, and similarly, an anchor point (anchor) or donor eNodeB 100 will transmit and/or receive signals to/from the UE104 via the relay node 103. The donor eNodeB 100 may also transmit and/or receive signals to/from UEs 105 directly connected to the eNodeB 100.

LTE-advanced, 3GPP release 10 will support a new control channel, the relay physical downlink control channel (R-PDCCH), which is transmitted later in a subframe than normal control signaling to the user equipment at the beginning of the subframe. Similar to PDCCH, R-PDCCH carries uplink grants or downlink assignments. Multiple R-PDCCHs and possibly other control channels (defined for relay operation) can be transmitted, and the time-frequency region in which they are transmitted is referred to herein as the "R-PDCCH region". The R-PDCCH region will typically not occupy the full system bandwidth during a subframe and can use the remaining resources for data transmission to UEs and/or RNs.

Multiplexing the R-PDCCH with other transmissions in the downlink subframe from the donor eNB can be performed using Frequency Division Multiplexing (FDM) or a combination of FDM and Time Division Multiplexing (TDM).

Considering first the possibility of multiplexing R-PDCCH data with other data in a subframe containing the R-PDCCH using FDM only, R-PDCCH transmission will start as soon as the RN is able to receive a transmission from the eNB, i.e. the control region 200 in the subframe, as shown in fig. 2A. This may be done directly after the control region 200 or possibly slightly later to allow for a transition from transmission to reception in the relay. In this case, the R-PDCCH region 202 spans the remainder of the subframe in time, i.e., transmission of the R-PDCCH ends at the end of the subframe, or possibly ends slightly earlier in order to allow for transition between reception and transmission in the relay.

As shown in fig. 2A, the use of FDM is beneficial because the R-PDSCH channel need not be defined, as further described below in connection with fig. 2B. The system is simplified to avoid this situation. However, when using FDM only, R-PDCCH control signaling cannot be decoded until the end of the subframe, which may increase latency in decoding of data transmission by the RN because control information in the R-PDCCH is needed before data payload decoding.

Another alternative is to use FDM + TDM to multiplex the R-PDCCH data with other data in the subframe containing the R-PDCCH, in which case the start of the R-PDCCH 210 is the same as in the FDM method, as shown in FIG. 2B. However, the end of the R-PDCCH transmission is significantly earlier in the subframe than in the FDM approach, which can be seen by comparing fig. 2A with fig. 2B, meaning that there will be downlink resources 212 after the R-PDCCH in the subframe. Those resources can be used, for example, to transmit eNB to RN data and are referred to herein as a relay physical downlink shared channel (R-PDSCH). Note that R-PDSCH cannot be used for eNB-to-UE transmissions, at least not for legacy UEs, as R-PDSCH is currently undefined in the LTE specifications. Also note that in the FDM + TDM approach, the R-PDCCH region spans a larger frequency bandwidth than in the FDM approach, assuming the same number of bits on the R-PDCCH, since it is shorter in time. As shown in fig. 2B, the combined use of FDM + TDM allows the R-PDCCH to be decoded earlier than in the case of FDM, which is beneficial from a latency perspective, but on the other hand, this approach requires the definition of the R-PDSCH to exploit the resources 212 behind the R-PDCCH region 210 and may result in inefficient resource utilization. Legacy UEs will not be able to process R-PDSCH and when scheduling such UEs, the time-frequency region otherwise used for R-PDSCH will therefore have to be left empty.

The disadvantages of the potential subframe structure discussed above with reference to fig. 2A and 2B are overcome by a subframe structure according to at least some embodiments of the present invention, which will now be discussed with reference to fig. 3. Similar to the potential subframe structure above, the R-PDCCH transmission will start as soon as the RN is able to receive a transmission from the eNB, i.e. after the control region 200 in the subframe. This may be done directly after the control region 200 or possibly slightly later to allow a transition from transmit to receive in the RN.

In the subframe structure of fig. 3, a time-frequency region 305, referred to herein as the R-PDCCH region, spans up to the end of a subframe 310 in which R-PDCCH data is transmitted (possibly except for any OFDM symbols required for transition in the RN) and is divided into two parts, as shown in fig. 3. The two portions are separated in time (i.e., in the time domain) into a first portion 300 and a second portion 302 of a time-frequency region 305 by a gap (split) 315. In some embodiments, the slot 315 may be a fixed slot, i.e., the position of the slot is fixed in the subframe. In other embodiments, slot 315 may be configurable or adaptable (adaptable) depending on the control information to be transmitted. For example, the gap may be configurable or adaptable depending on the respective number or size of downlink-related information and uplink-related information to be transmitted in a subframe in the system. The lengths in time of the first and second portions 300, 302 of the time-frequency region 305 may be specified as first and second numbers of OFDM symbols, specifying the lengths of the first and second portions of the time-frequency region, respectively.

In a first part 300 of the time-frequency region located earlier in a subframe 310 according to an embodiment, the R-PDCCH containing downlink related information is transmitted. The downlink related information may be, for example, scheduling assignments and, if defined, hybrid automatic repeat request (ARQ) acknowledgements. In a second part 302, located later in the subframe 310 than the first part, the R-PDCCH containing uplink related information such as scheduling grants is transmitted. In a further example, the uplink-related information transmitted in the second part may also include a hybrid ARQ acknowledgement. These hybrid ARQ acknowledgements may be transmitted, for example, by eNodeB 100 in response to information transmitted by RN103 in response to scheduling grants. Such a hybrid ARQ acknowledgement may be an indication to the RN103 that the transmitted information has been properly received, or that the RN103 is required to retransmit the information to the eNodeB 100.

The first portion 300 of the time-frequency region may also be referred to as a Downlink (DL) assignment region, and the second portion 302 of the time-frequency region may also be referred to as an Uplink (UL) grant region. With this subframe structure, downlink related information such as DL assignments (also referred to as scheduling assignments or downlink scheduling assignments) may be decoded at or after the first portion 300 of the time-frequency region 305 or the end 320 of the DL assignment region. Or in other words, when the first portion 300 of the time-frequency region 305 ends, the downlink-related information may be decoded. Similarly, uplink related information such as a UL grant (also referred to as a scheduling grant or uplink scheduling grant) may be decoded at or after the second portion 302 of the time-frequency region 305 or the end 330 of the UL assignment region, which end 330 may also be the end of the subframe 310. Or in other words, the uplink-related information may be decoded when the second portion 302 of the time-frequency region 305 ends or when the subframe 310 ends.

Note that the uplink related information may also be transmitted in the first zone 300, i.e. the first part 300 of the time-frequency zone 305, if not all available resources in the zone 300, i.e. the first part 300, have been used for downlink related information. In addition, it should be noted that the time-frequency region 305 spans about the same frequency bandwidth as the R-PDCCH region 202 of the FDM method, as shown in FIG. 2A, since the time-frequency region 305 spans about the same length in time as the time-frequency region of the FDM method, assuming that the number of bits on the R-PDCCH is the same. Because the time-frequency region 305 does not span the entire system bandwidth during a subframe, the remaining frequency resources 308 in the subframe (outside of the time-frequency region 305) can be used for data transmission to UEs and/or RNs.

With this structure shown in fig. 3, the latency benefits of having a downlink assignment available earlier in the subframe are achieved as in the FDM + TDM approach shown in fig. 2B. Furthermore, the R-PDSCH or other channel need not be defined, thereby simplifying the overall structure to a level of complexity similar to that of the FDM method shown in fig. 2A, since a later portion of the subframe is used for uplink grants, which is less time-critical from a latency perspective.

In many applications, it is desirable to time align the subframe structure (possibly within a small offset) in a cell controlled by a network node (e.g. eNB 100) and a cell controlled by an intermediate node (e.g. RN 103), see fig. 1. As a result of this, an intermediate node (such as RN103 in LTE) receiving transmissions from eNB100 on the same frequency resources as it uses to transmit to its user equipment 104 cannot receive normal control signaling from eNB100 at the beginning of a subframe, since RN103 needs to transmit control signaling to UE104 in that part of the subframe. This problem is solved in 3GPP release 10 by specifying that L1/L2 control signaling from eNB to RN is transmitted later in the subframe, as described earlier. Applying the sub-frame structure of the embodiment presented above with reference to fig. 3 also has the following effect: control signaling (i.e., control information) from the network node to the intermediate node is transmitted later in the subframe (i.e., at a later time within the subframe). Thus, embodiments of the present disclosure are applicable to applications in which the subframe structure in a network node controlled cell is time aligned with the subframe structure of an intermediate node controlled cell. However, the applicability of the subframe structure presented with reference to fig. 3 is not limited to environments where the subframe structure is time aligned between different cells in the radio-access network. For example, the subframe structure of fig. 3 may be applied to a hybrid environment, where the subframe structure of some cells is time aligned, e.g., between a cell controlled by a network node and a cell controlled by an intermediate node wirelessly connected to the network node, while the subframe structure of other cells is not time aligned. The subframe structure of fig. 3 may also be applied in environments where the subframe structure is not time aligned between different cells.

When an intermediate node (e.g., RN 103) receives a transmission from a network node (e.g., eNodeB 100) on the same frequency resources on which to transmit to its user equipment, the transmitter may cause interference to the receiver in the intermediate node.

According to a further embodiment of the present disclosure, one possibility to handle the interference problem is to operate the relay or RN103 such that the relay or RN103 is not transmitting to the terminal (e.g. UE104) when it should receive data from the donor eNodeB 100, i.e. creating a "gap" in the relay to UE transmission (e.g. in the transmission from RN103 to UE 104). These "gaps" (during which terminals including LTE Rel-8 terminals should not expect any relay transmission, e.g., any transmission from RN 103) can be created by configuring multicast/broadcast single frequency network (MBSFN) subframes, as shown in fig. 4. MBSFN subframe 450 contains a small control signaling portion 415 at the beginning of the subframe, followed by a silence period 460, where the UE does not expect any transmission from RN 103. This further embodiment has the following advantages: control signaling between eNB100 and RN103 has no effect on the behavior of UE104 controlled by RN 103. This embodiment is therefore compatible with legacy LTE terminals, such as 3GPP release 8 terminals.

In more detail, fig. 4 shows a sequence 420 of subframes, respectively comprising a control region 200 and a data region 440, in which control signals and data are respectively transmitted by the RN103 to the UE104, as indicated by the arrows under the sequence 420 of subframes. One subframe in sequence 420 is an MBSFN subframe 450, during which control signals are transmitted from RN103 to UE104 in a control signaling portion 415 in the beginning of MBSFN subframe 450. The control signaling portion 415 is substantially the same as the control region 200 of the non-MBSFN subframe. Following the control signaling portion 415, a quiet period 460 in the MBSFN portion of the MBSFN subframe follows, during which quiet period 460 no transmission from the RN103 to the UE104 occurs.

Fig. 4 further illustrates eNB transmitted subframe 310, in one embodiment, subframe 310 coincides in time with an MBSFN subframe in sequence 420 transmitted from RN103 to UE 104. According to the subframe structure of fig. 3, the subframe 310 is configured with a time-frequency region 305 for transmitting control information from the eNB100 to the RN 103. The time-frequency region 305 is divided into first and second portions separated by a gap 315 to enable transmission of time-critical control information in the first portion and less time-critical information in the second portion, as described earlier in the context of fig. 3. The subframe 310 also contains a data region 308 in which data is transmitted to the RN103 and/or to UEs 105 directly connected to the eNB 100. Control signals to UEs 105 directly connected to the eNB100 are transmitted in the control region 200 in the beginning of the subframe 310. Transmissions from eNB100 to RN103 are indicated by the straight arrow below subframe 310 in fig. 4, and transmissions to UEs 105 directly connected to eNB100 are indicated by the curved arrow.

In other embodiments, the subframe 310 transmitted by eNodeB 100 to RN103 may be an MBSFN subframe. In some subframes, RN-to-eNB transmissions (e.g., transmissions from RN103 to eNB 100) can be facilitated by not allowing any terminal-to-relay transmissions (e.g., transmissions from UE104 to RN 103) to be scheduled.

The effect from applying an embodiment of the present invention will now be described with reference to the combined flow chart and signalling scheme shown in figure 5. The combined flow chart and signaling scheme shows in more detail the actions performed during transmission of a subframe containing control information from a network node (exemplified in this disclosure by eNB 100) to an intermediate node (exemplified in this disclosure by RN103 of fig. 1). These actions may be performed in another order than indicated in the flow chart, and different actions may take longer or shorter times than shown in the flow chart. In a first block 510, a network node may transmit control signaling to a user equipment directly connected to the network node. Meanwhile, the intermediate node may transmit control signaling to a user equipment connected to the intermediate node at a time that may be the same or slightly different than a transmission time of the network node. The intermediate node then transitions from transmitting to receiving at block 515. At block 520, the network node transmits first control information, and at block 525, the intermediate node receives the first control information. After transmitting the first control information, the network node transmits second control information at block 530. Meanwhile, if the received first control information indicates that data directed to the intermediate node is transmitted in the subframe, the intermediate node having received the first control information begins decoding the data payload transmitted in the subframe at block 535. Upon decoding the data payload, the intermediate node transmits second control information at block 540. Typically, the decoding of the data payload at block 535 also continues after the end of the second portion of the time-frequency region and after the end of the sub-frame (where the data payload was received). Then, at block 545, the intermediate node transitions from receiving to transmitting, and at block 550, control signaling to the UE may be performed, as described earlier, but in subsequent subframes of the network node and the intermediate node, respectively. Finally, at block 555, the intermediate node takes action as indicated by the second control information.

A method in a network node 100 for transmitting control information from the network node 100 to an intermediate node 103 in a radio-access network 120 will now be described with reference to fig. 6. The control information is contained in a time-frequency region 305 transmitted after the control region 200 in the subframe 310. The control region 200 is transmitted in the beginning of the sub-frame 310. The control region 200 may be used for control signaling to the user equipment 105.

The time-frequency region 305 is divided such that the second portion 302 of the time-frequency region 305 is located later in the subframe 310 than the first portion 300 of the time-frequency region 305. The second portion 302 may thus be transmitted at a later time in the subframe 310 than the first portion 300. The method comprises the following steps, which may be performed in any suitable order:

step 610. the network node 100 transmits first control information in the first portion 300 of the time-frequency region 305, the first control information comprising a time-critical part of the control information. The first control information may relate to data transmitted in a (con) subframe 310. In a further example, the intermediate node 103 may require the first control information before decoding the data payload in the subframe 310. In some embodiments, the first control information is downlink related information. In some examples, the downlink-related information may be a scheduling assignment. According to a further embodiment, the uplink related information may be transmitted in the first portion 300 if resources are available in the first portion 300, which have not been used for downlink related information.

Step 620 the network node 100 transmits second control information in the second portion 302 of the time-frequency region 305, the second control information comprising a less time critical portion of the control information. The second control information is less time critical than the first control information. In some embodiments, the second control information may be uplink related information. In some embodiments, the uplink related information may be a scheduling grant.

In subframe 310, the first and second portions 300, 302 of the time-frequency region 305 may be separated in time (i.e., in the time domain) by a gap 315. The slot 315 may be a fixed slot at a fixed location in the subframe 310 or may be adaptable or configurable, in which case the location in the subframe may be set at, for example, a system configuration. According to further embodiments, the first portion 300 may contain a first set of OFDM symbols that follows a reserved set of OFDM symbols (e.g., 1-3OFDM symbols at the beginning of the subframe 310). The reserved set of OFDM symbols may be used for the control region 200. The second portion 302 of the time-frequency region 305 may contain a second set of OFDM symbols that follows the first set of OFDM symbols.

In some embodiments, the frequency resources used for transmitting control information by the network node 100 may be frequency resources also used by the intermediate node 103 for control signaling to the user equipment.

According to a further embodiment, the time-frequency region 305 transmitted after the control region 200 in the subframe 310 may be a time-frequency region for transmitting a control channel defined for a relay operation. In one example, the control channels may be R-PDCCH and may be used to signal (signal) or convey the first and second control information in the R-PDCCH.

In some further embodiments, the first and second control information may be transmitted during the silence period 460, at which time 460 the user equipment 104 connected to the intermediate node 103 does not expect any transmission from the intermediate node 103. In one example, the silence period 460 follows the control signaling portion 415 in the MBSFN subframe 450.

In a further embodiment, the subframe structure may be time aligned in the cell 102 controlled by the network node 100 and in the cell 102R controlled by the intermediate node 103.

In some embodiments, the network node 100 may be a donor eNB and the intermediate node 103 may be a relay node wirelessly connected to the radio-access network via a donor cell 102 controlled by the donor eNB. In other embodiments, the network node 100 and the intermediate node 103 may be relay nodes wirelessly connected to the radio-access network via a donor cell controlled by a donor eNodeB. In a further embodiment, the intermediate node 103 may be a user equipment wirelessly connected to the radio-access network via a donor cell controlled by the donor eNB.

A method in the intermediate node 103 for receiving control information in a subframe 310 from a network node 100 in the radio-access network 120 will now be described with reference to fig. 7A. The control information is contained in the time-frequency region 305 located after the control region 200 in the sub-frame 310. The control region 200 is located in the beginning of the sub-frame 310. The method comprises the following steps, which may be performed in any suitable order:

step 730. the intermediate node 103 receives the first control information in the first portion 300 of the time-frequency region 305. The first control information may relate to reception of data contained in the subframe 310. In a further example, the intermediate node 103 may require the first control information before decoding the data payload in the subframe 310. In some embodiments, the first control information is downlink related information. In some examples, the downlink-related information may be a scheduling assignment.

Step 735 the intermediate node 103 decodes the first control information. The decoding starts at or after the end 320 of the first portion 300 of the time-frequency region 305.

Step 740, when the first control information indicates that the subframe 310 has a data payload to the intermediate node 103, the intermediate node 130 receives and decodes the data payload in step 750. In some embodiments, during the second portion 302 of the time-frequency region 305, some data payloads may be decoded.

Step 755, the intermediate node 103 receives the second control information in the second portion 302 of the time-frequency region 305. The second control information may be less time critical than the first control information. In some embodiments, the second control information is uplink related information. In some examples, the uplink-related information may be a scheduling grant. The second control information may relate to uplink transmission of data to be included in another subframe.

According to some embodiments, the method for receiving control information may further comprise the following steps described with reference to fig. 7B:

step 760. the intermediate node 103 decodes the second control information. The decoding starts at or after the end 330 of the second portion 302 of the time-frequency region 305. The second control information may relate to uplink transmission of data to be included in another subframe.

Step 770 when the second control information indicates an uplink transmission opportunity for the intermediate node 103, the intermediate node 130 transmits data in another subframe in step 780.

The time-frequency region 305 may be divided such that the second portion 302 of the time-frequency region 305 is located later in the subframe 310 than the first portion 300 of the time-frequency region 305. In subframe 310, the first and second portions 300, 302 of the time-frequency region 305 may be separated in time (i.e., in the time domain) by a gap 315. The end 320 of the first portion 300 of the time-frequency region 305 may be temporally between said first and said second portion 300, 302 of the time-frequency region 305 at the gap 315. The end 320 of the second portion 302 of the time-frequency region 305 may be at the end of the sub-frame 310.

The slot 315 may be a fixed slot at a fixed location in the subframe 310 or an adaptable or configurable slot, in which case the location in the subframe may be set at, for example, the system configuration.

According to further embodiments, the first portion 300 may contain a first set of OFDM symbols that follow a reserved set of OFDM symbols, e.g., 1-3OFDM symbols at the beginning of the subframe 310. A reserved set of OFDM symbols may be used for the control region 200. The second portion 302 of the time-frequency region 305 may contain a second set of OFDM symbols, which follows the first set of OFDM symbols.

In some embodiments, the frequency resources used for receiving control information from the network node 100 may be frequency resources also used by the intermediate node 103 for control signaling to the user equipment.

According to a further embodiment, the time-frequency region 305 located after the control region 200 in the subframe 310 may be a time-frequency region for receiving a control channel defined for a relay operation. In one example, the control channels may be R-PDCCH, and the first and second control information may be signaled or transmitted in the R-PDCCH.

In some further embodiments, the first and second control information may be received during a quiet period 460, at which time 460 the user equipment 104 connected to the intermediate node 103 does not expect any transmission from the intermediate node 103. In one example, the silence period 460 follows the control signaling portion 415 in the MBSFN subframe 450.

In a further embodiment, the subframe structure may be time aligned in the cell 102 controlled by the network node 100 and in the cell 102R controlled by the intermediate node 103.

In some embodiments, the network node 100 may be a donor eNB and the intermediate node 103 may be a relay node wirelessly connected to the radio-access network via a donor cell 102 controlled by the donor eNB. In other embodiments, the network node 100 and the intermediate node 103 may be relay nodes wirelessly connected to the radio-access network via a donor cell controlled by a donor eNB. In a further embodiment, the intermediate node 103 may be a user equipment wirelessly connected to the radio-access network via a donor cell controlled by the donor eNB.

In order to perform the method steps of the above method for transmitting and receiving control information, the network node 100 as well as the intermediate node 103 may be implemented as the node 800 shown in fig. 8. The node 800 may also be a UE104, 105. The node 800, which in some embodiments is implemented as the UE104, relay 103 and eNodeB 100 of fig. 1, can be implemented using various components, e.g., in hardware and/or software. For example, as shown generally in fig. 8, such a node 800 (e.g., a UE, relay, or eNodeB as described above) can include a processor 802 (or multiple processor cores), a memory 804, one or more secondary storage devices 806 (e.g., external storage devices), an operating system 808 running on the processor 802 and using the memory 804, and corresponding applications 810. The application 810 may be, for example, a scheduler application for scheduling of transmission of control information and data payloads and/or a decoder application for decoding of control information and data payloads. An interface unit 812 may be provided to facilitate communication between the node 800 and the rest of the network or may be integrated into the processor 802. For example, interface unit 812 can include a transceiver 814 capable of communicating wirelessly over an air interface, e.g., as specified by LTE, including hardware and software capable of performing the necessary modulation, coding, filtering, and the like, as well as demodulation and decoding to process such signals, including multiplexing or demultiplexing R-PDCCH data as described above.

As described above, the network node 100 may be implemented as the node 800. The network node 100, 800 comprises a transceiver 814, the transceiver 814 being adapted to transmit control information in the subframe 310 from the network node 100, 800 to the intermediate node 103 in the radio-access network 120. The control information is contained in a time-frequency region 305 transmitted after the control region 200. The control region 200 is transmitted in the beginning of the sub-frame 310. The control region 200 may be used for control signaling to the user equipment 105.

The transceiver 814 is further adapted to transmit first control information in a first portion 300 of the time-frequency region 305 and to transmit second control information in a second portion 302 of the time-frequency region 305. The time-frequency region 305 is divided such that the second portion 302 is located later in the subframe 310 than the first portion 300. The second control information is less time critical than the first control information.

The first control information may relate to data transmitted in the subframe 310. In a further example, the intermediate node 103 may require the first control information prior to decoding of the data payload in the subframe 310. In some embodiments, the first control information may be downlink related information and/or the second control information may be uplink related information. In some embodiments, the downlink related information may be a scheduling assignment and/or the uplink related information may be a scheduling grant. According to a further embodiment, the uplink related information may be transmitted in the first portion 300 if resources are available in the first portion 300, which have not been used for downlink related information.

In some embodiments, the transceiver 814 of the network node 100 may be adapted to transmit control information on frequency resources that are also used by the intermediate node 103 for control signaling to the user equipment.

In some further embodiments, the transceiver 814 in the network node 100 may be adapted to transmit the first and second control information during the silence period 460, at which time 460 the user equipment 104 connected to the intermediate node 103 does not expect any transmission from the intermediate node 103. In one example, the silence period 460 follows the control signaling portion 415 in the MBSFN subframe 450.

In subframe 310, the first and second portions 300, 302 of the time-frequency region 305 may be separated in time (i.e., in the time domain) by a gap 315. The slot 315 may be a fixed slot at a fixed location in the subframe 310 or an adaptable or configurable slot, in which case the location in the subframe may be set at, for example, a system configuration.

According to further embodiments, the first portion 300 may contain a first set of OFDM symbols that follow a reserved set of OFDM symbols, e.g., 1-3OFDM symbols at the beginning of the subframe 310. A reserved set of OFDM symbols may be used for the control region 200. The second portion 302 of the time-frequency region 305 may contain a second set of OFDM symbols, which follows the first set of OFDM symbols.

According to a further embodiment, the time-frequency region 305 transmitted after the control region 200 in the subframe 310 may be a time-frequency region for transmitting a control channel defined for a relay operation. In one example, the control channels may be R-PDCCH, and the first and second control information may be signaled or transmitted in the R-PDCCH.

In a further embodiment, the subframe structure may be time aligned in the cell 102 controlled by the network node 100 and in the cell 102R controlled by the intermediate node 103.

In some embodiments, the network node 100 may be a donor eNB and the intermediate node 103 may be a relay node wirelessly connected to the radio-access network via a donor cell 102 controlled by the donor eNB. In other embodiments, the network node 100 and the intermediate node 103 may be relay nodes wirelessly connected to the radio-access network via a donor cell controlled by a donor eNB. In a further embodiment, the intermediate node 103 may be a user equipment wirelessly connected to the radio-access network via a donor cell controlled by the donor eNB.

As described in the introduction to the description of fig. 8 above, intermediate node 103 may be implemented as node 800. The intermediate node 103, 800 is adapted to receive control information in the subframe 310 from the network node 100 in the radio-access network 120. The control information is contained in the sub-frame 310 in the time-frequency region 305 transmitted after the control region 200. The control region 200 is located in the beginning of the sub-frame 310.

The intermediate node 103, 800 comprises a transceiver 814, the transceiver 814 being adapted to receive the first control information in the first part 300 of the time-frequency region 305 and to receive the second control information in the second part 302 of the time-frequency region 305.

The first control information may relate to reception of data contained in the subframe 310. In a further example, the intermediate node 103 may require the first control information prior to decoding of the data payload in the subframe 310. In some embodiments, the first control information may be downlink related information. In some examples, the downlink-related information may be a scheduling assignment.

The second control information may be less time critical than the first control information. In some embodiments, the second control information may be uplink related information. In some examples, the uplink-related information may be a scheduling grant. The second control information may relate to uplink transmission of data contained in another subframe.

The transceiver 814 is further adapted to receive a data payload when the first control information indicates that the subframe 310 contains a data payload to the intermediate node 103.

The transceiver 814 may be further adapted to transmit data in another subframe when the second control information indicates an uplink transmission opportunity for the intermediate node 103.

In some embodiments, the transceiver 814 of the intermediate node 103 may be adapted to receive control information from the network node 100 on frequency resources that are also used by the intermediate node 103 for control signaling to the user equipment.

In some further embodiments, the transceiver 814 in the intermediate node 103 may be adapted to receive the first and second control information during the silence period 460, at which time the user equipment 104 connected to the intermediate node 103 does not expect any transmission from the intermediate node 103. In one example, the silence period 460 follows the control signaling portion 415 in the MBSFN subframe 450.

The intermediate node 103, 800 further comprises a processor 802, the processor 802 being adapted to control the transmission and reception of said transceiver 814. The processor 802 is further adapted to decode the first control information. The processor 802 is adapted to start decoding the first control information at or after the end 320 of the first portion 300 of the time-frequency region 305.

The processor 802 is further adapted to determine whether the first control information indicates a data payload to the intermediate node 103. The processor 802 is adapted to decode the data payload when the first control information indicates that the sub-frame 310 has a data payload to the intermediate node 103. In some embodiments, during the second portion 302 of the time-frequency region 305, some of the data payload may be decoded.

The processor 802 may be further adapted to decode the second control information and to begin decoding the second control information at or after the end 330 of the second portion 302 of the time-frequency region 305 in the subframe 310. The processor 802 may be further adapted to determine whether the second system information is directed to the intermediate node 103. The second control information may relate to uplink transmission of data to be included in another subframe.

The time-frequency region 305 may be divided such that the second portion 302 of the time-frequency region 305 is located after the first portion 300 of the time-frequency region 305 in the sub-frame 310. In subframe 310, the first and second portions 300, 302 of the time-frequency region 305 may be separated in time (i.e., in the time domain) by a gap 315. The end 320 of the first portion 300 of the time-frequency region 305 may be temporally between said first and said second portion 300, 302 of the time-frequency region 305 at the gap 315. The end 320 of the second portion 300 of the time-frequency region 305 may be at the end of the sub-frame 310.

The slot 315 may be a fixed slot at a fixed location in the subframe 310 or an adaptable or configurable slot, in which case the location in the subframe may be set at, for example, a system configuration.

According to further embodiments, the first portion 300 may contain a first set of OFDM symbols that follow a reserved set of OFDM symbols, e.g., 1-3OFDM symbols at the beginning of the subframe 310. The reserved set of OFDM symbols may be used for the control region 200. The second portion 302 of the time-frequency region 305 may contain a second set of OFDM symbols, which follows the first set of OFDM symbols.

According to a further embodiment, the time-frequency region 305 located after the control region 200 in the subframe 310 may be a time-frequency region for receiving a control channel defined for a relay operation. In one example, the control channels may be R-PDCCH, and the first and second control information may be signaled or transmitted in the R-PDCCH.

In a further embodiment, the subframe structure may be time aligned in the cell 102 controlled by the network node 100 and in the cell 102R controlled by the intermediate node 103.

In some embodiments, the network node 100 may be a donor eNB and the intermediate node 103 may be a relay node wirelessly connected to the radio-access network via a donor cell 102 controlled by the donor eNB. In other embodiments, the network node 100 and the intermediate node 103 may be relay nodes wirelessly connected to the radio-access network via a donor cell controlled by a donor eNB. In a further embodiment, the intermediate node 103 may be a user equipment wirelessly connected to the radio-access network via a donor cell controlled by the donor eNB.

The proposed mechanism for transmitting and receiving control information may be implemented by one or more processors, such as processor 802 in node 800 shown in fig. 8, in conjunction with computer program code for performing the functions of the proposed solution for transmitting and receiving control information, respectively. The program code mentioned above may also be provided as a computer program product, for example in the form of a data carrier carrying computer program code for performing the proposed solution when being loaded into the node 800. One such carrier may be in the form of a CD ROM disc, however, it is feasible to utilize other data carriers such as memory sticks. The computer program code can furthermore be provided as pure program code on a server and downloaded to the node 800 remotely.

The foregoing description of exemplary embodiments provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention.

When the word "comprising" or "comprising … …" is used, it should be construed as non-limiting, i.e., meaning "consisting of at least …".

The invention is not limited to the preferred embodiments described above. Various alternatives, modifications, and equivalents may be used. The above-described embodiments are therefore not to be taken as limiting the scope of the invention, which is defined by the appended claims.

Claims (32)

1. A method in a network node (100) for transmitting control information in a subframe (310) from the network node (100) to an intermediate node (103) in a radio-access network (120), wherein the control information is contained in a time-frequency region (305) transmitted after a control region (200), the control region (200) being transmitted in the beginning of the subframe (310), the method characterized by:

transmitting (610, 620) first control information in a first portion (300) of the time-frequency region (305) and second control information in a second portion (302) of the time-frequency region (305), wherein the time-frequency region (305) is divided such that the second portion (302) is located later in the subframe (310) than the first portion (300), and wherein the second control information is less time critical than the first control information, wherein the first control information is downlink related information and the second control information is uplink related information.

2. The method of the preceding claim, wherein the downlink related information is a scheduling assignment.

3. The method of claim 1, wherein the uplink-related information is a scheduling grant.

4. The method according to any of claims 1-3, wherein the uplink related information is transmitted in the first part (300) if all available resources in the first part (300) have not been used for downlink related information.

5. The method according to any of claims 1-3, wherein the first control information relates to data transmitted in the subframe (310).

6. The method according to any of claims 1-3, wherein the second control information relates to an uplink transmission of data to be contained in another subframe.

7. The method according to any of claims 1-3, wherein the first control information is required prior to decoding of a data payload in the subframe (310).

8. The method according to any one of claims 1-3, wherein the first and second portions (300, 302) of the time-frequency region (305) are separated in time by a gap (315).

9. The method of the preceding claim, wherein the gap (315) is a fixed gap.

10. The method of claim 8, wherein the slot (315) is an adaptable or configurable slot.

11. The method according to any of claims 1-3, wherein the first portion (300) comprises a first set of OFDM symbols following a reserved set of OFDM symbols for the control region (200), and the second portion (302) comprises a second set of OFDM symbols following the first set of OFDM symbols.

12. The method according to any of claims 1-3, wherein frequency resources used by the network node (100) for transmitting the control information are also used by the intermediate node (103) for control signaling to user equipments.

13. The method according to any of claims 1-3, wherein the time-frequency region (305) transmitted after the control region (200) in the subframe (310) is a time-frequency region used for transmitting control channels defined for relay operation.

14. The method of the preceding claim, wherein the control channel is an R-PDCCH, and the first and second control information are signaled in the R-PDCCH.

15. The method according to any of claims 1-3, wherein the first and second control information are transmitted during a quiet period (460), at which quiet period (460) no transmission from the intermediate node (103) is expected by a user equipment (104) connected to the intermediate node (103).

16. The method of the preceding claim, wherein the muting period (460) follows a control signaling portion (415) in an MBSFN subframe (450).

17. The method according to any of claims 1-3, wherein the subframe structure is time aligned in a cell (102) controlled by the network node (100) and in a cell (102R) controlled by the intermediate node (103).

18. The method according to any of claims 1-3, wherein the network node (100) is a donor eNB and the intermediate node (103) is a relay node wirelessly connected to the radio-access network via a donor cell (102) controlled by the donor eNB.

19. A network node (100, 800) comprising a transceiver (814), the transceiver (814) being adapted to transmit control information in a subframe (310) from the network node (100, 800) to an intermediate node (103) in a radio-access network (120), wherein the control information is contained in a time-frequency region (305) transmitted after a control region (200) transmitted in the beginning of the subframe (310), the network node (100, 800) being characterized by:

the transceiver (814) is further adapted to transmit first control information in a first portion (300) of the time-frequency region (305) and second control information in a second portion (302) of the time-frequency region (305), wherein the time-frequency region (305) is divided such that the second portion (302) is located later in the subframe (310) than the first portion (300), and wherein the second control information is less time-critical than the first control information, wherein the first control information is downlink-related information and the second control information is uplink-related information.

20. The network node (100, 800) of the preceding claim, in which the downlink related information is a scheduling assignment.

21. The network node (100, 800) according to claim 19, wherein the uplink related information is a scheduling grant.

22. The network node (100, 800) of any of claims 19-21, wherein the time-frequency region (305) transmitted after the control region (200) in the subframe (310) is a time-frequency region used for transmitting control channels defined for relay operation.

23. The network node (100, 800) according to any of claims 19-21, wherein the network node (100) is a donor eNB and the intermediate node (103) is a relay node wirelessly connected to the radio-access network via a donor cell (102) controlled by the donor eNB.

24. The network node (100, 800) of any of claims 19-21, in which the network node and the intermediate node are relay nodes wirelessly connected to the radio-access network via a donor cell controlled by a donor eNB.

25. The network node (100, 800) of any of claims 19-21, wherein the relay node is a user equipment wirelessly connected to the radio-access network via a donor cell controlled by a donor eNB.

26. A method in an intermediate node (103) for receiving control information in a subframe (310) from a network node (100) in a radio-access network (120), wherein the control information is contained in a time-frequency region (305) located after a control region (200), the control region (200) being located in the beginning of the subframe (310), the method characterized by:

receiving (730) first control information in a first portion (300) of the time-frequency region (305);

decoding (735) the first control information, wherein the decoding starts at or after an end (320) of the first portion (300) of the time-frequency region (305);

receiving and decoding (750) a data payload to the intermediate node (103) in the subframe (310) when (740) the first control information indicates the data payload; and

receiving (755) second control information in a second portion (302) of the time-frequency region (305), wherein the first control information is downlink-related information and the second control information is uplink-related information.

27. The method according to the preceding claim, the method further comprising the steps of:

decoding (760) the second control information, wherein the decoding starts at or after an end (330) of the second portion (302) of the time-frequency region (305) in the subframe (310); and

transmitting (780) data in another subframe when the second control information indicates an uplink transmission opportunity for the intermediate node (103).

28. The method of claim 26 or 27, wherein the downlink related information is a scheduling assignment.

29. The method of claim 28, wherein the uplink-related information is a scheduling grant.

30. The method of claim 26, wherein the uplink-related information is a scheduling grant.

31. An intermediate node (103, 800) adapted to receive control information in a subframe (310) from a network node (100) in a radio-access network (120), wherein the control information is contained in a time-frequency region (305) located after a control region (200), the control region (200) being located in the beginning of the subframe (310), characterized in that the intermediate node (103, 800) comprises:

a transceiver (814) adapted to receive first control information in a first portion (300) of the time-frequency region (305) and to receive second control information in a second portion (302) of the time-frequency region (305), the transceiver (814) further adapted to receive a data payload to the intermediate node (103) when the first control information indicates that the subframe (310) contains the data payload; and

a processor (802) connected to the transceiver (814) and adapted to control transmission and reception of the transceiver (814), the processor (802) further adapted to decode the first control information, wherein the processor (802) is adapted to start decoding the first control information at or after an end (320) of the first portion (300) of the time-frequency region (305), the processor (802) further adapted to decode the data payload when the first control information indicates the data payload to the intermediate node (103) in the subframe (310), wherein the first control information is downlink related information and the second control information is uplink related information.

32. The intermediate node (103, 800) of the preceding claim, wherein the processor (802) is further adapted to decode the second control information, and to start decoding the second control information at or after an end (330) of the second portion (302) of the time-frequency region (305) in the subframe (310), and wherein the transceiver (814) is further adapted to transmit data in another subframe when the second control information indicates an uplink transmission opportunity for the intermediate node (103).