Radio resource assignment in control channel in wireless communication systems

[0001] The present description relates generally to wireless communication, and more specifically to control channel signaling for shared channels in wireless communication systems, e.g., cellular communication networks, and corresponding facilities and methods.

BACKGROUND ART [0002] Time division multiplexing (TDM) and frequency division multiplexing (FDM) methods, including their hybrids, it was proposed in addition to the separate and common coding of the control channel signaling for scheduling downlink data transmission in accordance with the Long Term Evolution (LTE) specifications of terrestrial radio access of the UMTS system (UTRĄ - UMTS Terrestrial Radio Access) and the UTRRA network (UTRAN - UTRĄ NetWork) . In TDM and FDM transmissions, with control channel signaling, control information for downlink and uplink assignments may be transmitted in the first few symbols of the downlink frame, or it may be spread over the entire length of the frame. The frame duration is about 0.5 ms, although other duration values ​​are possible.

[0003] PCT Publication No. WO 2005/050852 describes a method and system for providing channel assignment information used to support uplink and downlink (UL) links. The system includes at least one Node-B node and at least one wireless transmit / receive unit (WTRU). The WTRU receives a message from the Node-B via a common control channel, which is used to transmit channel allocation information for both UL and DL transmissions. The message indicates whether the message is intended for allocating radio resources to the UL channel or to the DL channel. The WTRU checks if the message is intended for the WTRU, and if so, the WTRU determines whether the message is intended for the allocation of radio resources to the UL channel or to the DL channel and takes appropriate action. U.S. Patent Application published after US 2003/0112778 describes an effective method and apparatus for multicast distribution for packet data systems. A single MAC_ID is used for broadcasting to subscribers. When using channel group qualitative information, the base station determines the identity of the subscriber with the worst channel conditions. Then the timing and multicast transmission format is adjusted so that the subscriber with the worst channel conditions is able to receive the transmission, so it is likely that other subscribers will also be able to receive the transmission. Thus, only one MACJD is needed to set up a single broadcast instead of sending multiple transmissions to multiple subscribers.

[0004] In the publication entitled "WCDMA for UMTS" (WCDMA for UMTS), aut. Harri Hofma, Antti Toskala, 2000, Wiley and Sons, ISBN: 0 471 72051 8, pages 95-97, subsection 6.4.5, describes the dedicated link channel transmitted as a dedicated downlink dedicated physical channel (Downlink DP-CH Downlink Dedicated Physical Channel). The DPCH down channel uses time multiplex to transmit physical control information and user data. The terms "Dedicated Physical Data Channel" (DPDCH) and "Dedicated Physical Control Channel" (DPCCH 2)

Dedicated Physical Control Channel) are used to define dedicated downlink channels. The downlink DPCH channel for performance improvement can benefit from broadcast diversification, either in open loop or in closed loop. When diversifying the open loop broadcast, the information is coded according to the broadcast by two antennas.

[0005] The various aspects, characteristics and advantages of the invention will be apparent to those skilled in the art upon careful consideration from the following detailed description and the accompanying drawings described below. Drawings can be simplified for clarity, and not necessarily drawn to scale.

SUMMARY OF THE INVENTION [0006] The present invention provides a method for a wireless communication device having the features of claim 1. 1, and a device for wireless communication with the characteristics of claim 1. 14.

[0007] Other embodiments of the invention are the subject of the dependent claims.

DESCRIPTION OF THE FIGURES [0008] Fig. 1 shows a wireless communication system.

[0009] Fig. 2 shows a radio frame including a composite control channel with some set of control channel elements.

[0010] Fig. 3 shows a composite control channel with various types of control channel elements.

[0011] Fig. 4 shows a flow diagram of the process.

[0012] Fig. 5 is another flowchart of a process.

DETAILED DESCRIPTION [0013] Fig. 1 shows a wireless communication system 100 comprising base units serving multiple cells, forming a distributed network in a certain geographical area. The base unit may also be referred to as an access point, access terminal, Node-B node, or using similar terminology known in the art. One or more base units 101 and 102 support remote units 103 and 110 within a service area, cell, or within its sector. Remote units may also be referred to as subscriber units, mobile units, users, terminals, subscriber stations, user equipment (UE), or according to other terminology known in the art. The base units of the network communicate with remote units, performing functions such as scheduling terminals when receiving or transmitting data using available radio resources. The wireless network also performs management functions including data routing, access control, subscriber billing, terminal authentication, etc., which can be controlled by other objects on the network, which is familiar to those skilled in the art.

[0014] Base units 101 and 102 transmit downlink communication signals 104 and 105, operating remote units on at least part of the same resources (time and / or frequency). Remote units 103 and 110 communicate with one or more base units, 101 and 102, via uplink communication signals 106 and 113. The one or more base stations may include one or more transmitters and one or more receivers that support remote units. The number of transmitters in the base unit may be associated, for example, with the number of transmit antennas 109 in the base unit. When multiple antennas are used to support each sector providing various advanced communication modes, e.g. adaptive beamforming, broadcast diversification, SDMA broadcasting and multiple streaming etc., it is possible to deploy multiple base units. These base units within a sector can be highly integrated and can share various hardware and software components. For example, all base units located together to support a cell may constitute a known traditional base station.

Remote units can also contain one or more transmitters and one or more receivers.

The number of transmitters can be associated, for example, with the number of transmit antennas in the remote unit.

In one implementation, the communication system uses OFDMA access or next generation FDMA based single carrier FDMA for interlinked transmission, e.g. interleaved FDMA (IFDMA - Localized FDMA), OFD (LFDMA), OFDM with DFT (DFT-SOFDM - DFT-Spread OFDM) and IFDMA or LFDMA access. In other implementations, the architecture may also include scatter methods, such as Direct-Sequence CDMA (DS-CDMA), Multi-Carrier CDMA (MC-CDMA Multi-Carrier CDMA), and Multi-Direct CDMA CDMA carriers (MC-DS-CDMA Multi-Carrier Direct Sequence CDMA), orthogonal frequency and code division multiplexing (OFCDM) with one- and two-dimensional scattering, or simpler multiplexing / multiple access methods with time and frequency division.

[0016] Generally, the wireless communication network scheduling object, located, for example, in each base unit 101 and 102 in Fig. 1, allocates, i.e. allocates radio resources to remote units in the network. Each of the base units includes a scheduling block for scheduling and allocating resources to remote units, in respective service areas or cells or sectors. In multiple access schemes, for example based on OFDM methods and the Standard according to Long Term Evolution in the UTRA / UTRAN Study Item specification in 3GPP (also known as the development of the UTRA / UTRAN (EUTRA / EU-TRAN) standard), scheduling can take place in time and frequency using the Frequency Selective (FS). In some implementations, each remote unit may provide a frequency band channel quality indicator (CCI) or other metric to the scheduler to enable scheduling.

[0017] In OFDM systems or in OFDM-like systems, such as DFT-SOFDM and IFDMA, for example, resource allocation is a frequency and time allocation that maps information for a specific base unit about subcarrier resources from the set of available subcarriers determined by the scheduler. This allocation may depend, for example, on the frequency band selective quality indicator (CQI) or other metric provided by the user equipment, UE, to the scheduling block. The channel coding rate and modulation method may be different for different parts of the subcarrier resources, so they are determined by the scheduling block, and may also depend on the CQI indicator or other metric being reported. In time-division multiplexed networks, resource allocation is the allocation to subcarrier resources from a set of available subcarriers specified by the scheduling block mapping the code to a specific base unit. [0018] Fig. 2 shows the frame 200, which is part of the radio frame. A radio frame usually includes a set of frames that can form a combined frame string. In Figure 2, each frame includes a portion 210 of the composite control channel including at least two control channel elements. Fig. 2 shows a composite control channel including a set of control channel elements 212, 214, 216 and 218. Each of the control channel elements comprises a code word that provides a physical mapping of the logical control channel to a sequence of symbols, e.g., QAM symbols. Control channel elements are usually not of the same type. For example, in Fig. 2, control channel elements 212 and 218 have different sizes. The control channel elements may also be intended for ufa uplink or downlink assignments, and have different user information assigned. Control channel elements can also be assigned to different versions of requirements. In some implementations, the composite control channel includes reference symbols, e.g., pilot symbols, that are different from the control channel elements. These reference symbols are usually read by remote units.

[0019] Each frame corresponds to a certain transmission time interval (TTI). An example TTI time is 1 ms. In one implementation, a single TTI is 1 ms or 2 ms long, with the TTI divided into two 0.5 ms subframes. However, this structure implies the need to address multiple resource blocks, i.e. 0.5 ms more than the number of resource blocks in each individual sub-frame, unless the resource block definition (RB. - resource block) is extended with automatic RB determination. as extending beyond the total length of the TTI, regardless of the duration of the TTI. However, this can lead to inefficiency, in the form of excessive volume per RB. In the case of defining the RB block as exceeding a part of the TTI length, it would be possible to address each of the resource blocks independently in many sub-frames making up the TTI. Accordingly, mechanisms are needed for the assignment of signal resources, in the case of a frame, or TTI, composed of connected sub-frames. In addition, mechanisms are needed to allocate resources, based on the needs of individual UEs, with less resources allocated to UEs supported with smaller packets, and more resources allocated to UEs supported with larger packets. In the case of the Universal Mobile Telecommunications System UMTS (UMTS - Universal Mobile Telecommunications System), TTI is defined as the length of time in which the transport block is transmitted. A transmission block or transport block is a block of jointly coded data protected by a single CC sum. In the present case, another definition of TTI could include the length of transmission controlled by a single control channel signaling event.

[0020] In one embodiment, each control channel element includes only radio resource assignment information, e.g., a code word addressed only to a single wireless communication object, e.g., one of the remote units 110, 103 in Fig. 1. Assignment information the radio resource includes, among other things, specialized remote unit information and the allocation of the radio resource of time and frequency. In other implementations, among others, specialized remote unit information and time and frequency radio resource allocation. In other implementations, the radio resource allocation information may further include modulation information, code speed, information block size, and antenna mode indicator, and other information.

In one embodiment, the wireless communication network infrastructure object, e.g., the scheduling block, may address more than one control channel element to the same wireless communication entity, e.g., one of the remote units 110 or 103 in Fig. 1. More specifically, the control channel may include a first version of the code word comprising in the first control channel element resource allocation in the composite control channel, and a second version of the code word comprising in the second control channel element resource allocation in the composite control channel, both the first and the second version the codeword is addressed to the same mobile unit. In one implementation, the first and second codeword versions are the same, and in another implementation, the first and second codeword versions are different. Whether code words addressed to the same object are different or the same affects how the addressed object combines the control channel elements in combination, as described below. Thus, the wireless communication infrastructure object transmits a composite control channel comprising at least two control channel elements, each of which comprises at least two control channel elements, and each of these elements includes respective versions of the first and second codeword addressed to this the object itself. In some situations, a wireless network infrastructure object may, usually based on channel and object conditions, broadcast a composite control channel including a single control channel element addressed to that object.

[0022] In the examples where the composite control channel includes a composite control channel comprising at least two different types of radio resource allocation control channel elements, the remote unit, upon receiving the composite control channel, typically determines the number of types of control channel elements constituting the composite control channel. In one example, the composite control channel includes type indicator information for each control channel element constituting the composite control channel. The remote unit may thus determine the number of types of control channel elements based on the type indicator information. In Fig. 3, the radio frame 300 includes a composite control channel 310 including a first type 312 of the control channel element, and a second type 316 of the control channel element. The first type of control channel element is identified by the first pointer, e.g., bit sequence, 314, attached to the last element of the first type of control channel. The second type of control channel element is identified by a second indicator 318 attached to the last control channel element of the second type. In another example, indicators 314 and 318 are not present and the type of control channel element is determined after the control element has been successfully decoded. For example, the type bit may point to the uplink or downlink control in the decoded user information. The control may be addressed to a single UE by the color coded sum of CRC or by other means. In accordance with another aspect of the invention, the remote unit determines the number of control channel elements forming at least one or at least control channel elements in the composite control channel. Fig. 3 shows only an illustrative implementation of the physical distribution of control channel elements in the radio sub-frame. In an alternative implementation, the distribution may be considered as some logical distribution, where the control channel elements contain the number of sub-frames distributed throughout the frame.

[0023] In one example, determining the number of types of control channel elements constituting the composite control channel includes determining the number of uplink control channel elements and determining the number of downlink control channel elements. The number of uplink control channel elements may be determined based on the first bit sequence embedded in the frame. In one example, the number of uplink and downlink control channel elements are determined based on the location of the first and second bit sequences within the frame. Alternatively, the use of different bit sequences can be used to indicate different numbers of control channel elements. For example, the first bit sequence may indicate the first β

the number of uplink elements and the second bit sequence may indicate the second number of uplink elements.

[0024] In some embodiments, the composite control channel includes a first portion of the composite control channel in a first receiving band at a first center frequency and a second composite control channel in a second receiving band at a second center frequency. This control channel structure can be implemented to support remote users having limited receiving bandwidth. More generally, the composite control channel may be divided into portions of the composite control channel at respective center frequencies. For example, terminals may have reception bands limited to 10 MHz, while the carrier bandwidth is 20 MHz. In order to support such terminals with a limited minimum bandwidth, it may be necessary to map a complex control channel to both the 10 MHz lower subband and 10 MHz upper subband. 10 MHz terminals work in one subband, either upper or lower, and receive the appropriate composite control channel.

[0025] In the process 400 of Fig. 4, in step 410, in a wireless communication entity, e.g., a remote unit, the terminal receives a composite control channel comprising at least two control channel elements. In one embodiment, each control channel element includes only radio resource allocation information addressed to a single wireless communication object only.

[0026] In Figure 4, in step 420, two or more control channel elements are combined before decoding in step 430. However, in general, the remote unit may attempt to decode a single control channel element without first combining the elements or may attempt to decode a single control channel element after decoding or attempting to decode connected items. Whether or not pairing is needed usually depends on whether the remote unit successfully decodes individual control channel elements. Linking may be needed, for example, in situations where a cyclic redundancy check (CRC) error occurs, another verification check after decoding a channel element, or where decoding is not successful. Information verification typically includes special remote unit information contained in a decoded channel element, or masked encoded control channel element, or masked or fed to CRC for CRC encoding control.

[0027] In some implementations, each of the set of control channel elements has an associated base indicator that can be used as a basis for connecting control channel elements. For example, if the composite control channel includes 12 control channel elements, then 4 of these elements may be assigned the same basic indicator and may be used as a basis for decoding and combining and decoding control channel elements. In implementations in which the control channel is divided into parts at the respective center frequencies, as described above, the remote unit only connects the control channel elements of the same control channel part. In other words, control channel elements from different parts of the control channel are not combined.

[0028] In some implementations, the remote unit combines at least two control channel elements, a composite control channel, each control channel element being of a type that only contains radio resource assignment information addressed only to a single communication object. Linking may be required, for example, in situations where cyclic redundancy check (CRC) or other information validation and results in a negative result after decoding a single channel element control element, or situations where decoding is not successful.

However, usually the remote unit may decode the control channel element without first connecting.

[0029] In one embodiment, the at least two control channels are combined by adding together the soft decision information output from the first and second codeword, the first codeword information being in the first control channel element and the second codeword information being in the second element control channel. In this type of combination, the elements of a complex control channel are temporarily ordered and stacked on top of each other (convection code - Chase combining). Overlap can include weighted summation, MaxRatio Combining, or aggregation of likelihood indicators (LLR), etc. The assumption is that the first and second codeword information is addressed to the same remote unit. If not, then either decoding or verification information verification after decoding will give a negative result. In the event of an error, the remote unit may form a different combination of control channel elements, for example by combining another set of control channel elements or by including an additional element.

[0030] In another embodiment, at least two control channel elements are combined by rearranging and summing the soft decision information derived from the other information of the first and second code words, wherein the first code word information is in the first control channel element and the second code word information located inside the second element of the control channel. For example, the first code word and the second code word may include subsets of the information set and parity bits generated in the channel encoder and at a lower speed. The subsets may be non-overlapping or partially overlapping. Soft decision information corresponding to the overlapping bit positions of the codeword is usually aggregated in the remote unit, while non-overlapping bit positions are usually rearranged to positions suitable for decoding.

[0031] In one embodiment, the remote unit connects at least two control channel elements according to predefined combinations of control channel elements. For example, at least one of the predefined combinations comprises a combination of at least two logically continuous control channel elements. Logically continuous control channel elements may be physically continuous or not. For example, if a certain set of frequency scattered subcarriers (so-called frequency comb) is used for one control channel element, the other control channel element may or may not physically occupy the subcarriers adjacent the first control channel element. Or, if the logical and physical arrangements of the subcarriers are identical, that is, if there is a one-to-one mapping of logical and physical subcarriers, then logical neighborhood implies physical neighborhood and vice versa. In other implementations, at least two non-adjacent control channel elements are combined, wherein these non-adjacent control channel elements can be physical or logical.

[0032] In some implementations, the order in which the remote unit proceeds to combine control channel elements according to predefined combinations is based on one or more hypotheses or assumptions. For example, control channel elements may be combined based on determining the number of control channel elements constituting the composite control channel. these

The determination also includes determining the number of control channel elements constituting a specific type of control channel element in implementations where the composite control channel comprises more than one type of elements as described above. The number of control channel elements may be determined, e.g., based on the existence of numerical information about the number of control channel elements contained in the composite control channel. For example, the number of control channel elements may be determined based on the bit sequence attached to the composite control channel based on the bit sequence attached to the composite control channel. In one implementation, different bit sequences indicate different numbers of control channel elements. In another implementation, the presence of the bit sequence in the frame indicates the number of control channel elements. In this latter implementation, the same bit sequence can be used to indicate different numbers of control channel elements, depending on where the bit sequence is located in the frame. The number of control channel elements can thus be determined based on data or messages exchanged between the wireless communication device and the network infrastructure object. This may occur in a message sent to all remote units via an occasional broadcast channel or in a broadcast message sent in each TTI. The number of control channel elements or a subset of control channel elements that should be decoded by a remote unit can also be sent via a message dedicated to that remote unit.

[0033] In one embodiment, the control channels may be one or two control channel elements, with the size of the control element indicating the type of control element. Convolutional coding can be used for the controls. The decoder can decode the first control element, check the CRC, and then stop decoding if the control element is intended for the user. If not, decoding can start from the point just before inserting the end bit on the first control element to the end of the lattice combination of both controls. The CRC sum is checked again. In this way, decoding of the control channel can be achieved with less effort than if the control elements were decoded from the beginning of the matrix combination. It should be noted that the code rate for one and two controls in this implementation must be the same.

[0034] In some implementations, a portion of the composite control channel is allocated to allocating radio resources in each frame. In these implementations, the unallocated portion of the control channel may be used for data transfer. Thus, the wireless communication network infrastructure object, e.g., the scheduling block, may allocate a portion of the control channel to allocate radio resources in each frame by embedding the bit sequence in the corresponding frame. In one embodiment, the location of the bit sequence in the frame indicates the size of the control channel, e.g., how many control channel elements are allocated to allocate radio resources to one or more remote units. In this implementation, control channel elements can be addressed only to a single remote unit, or to more than one remote unit. More generally, the network infrastructure object can dynamically change a portion of the control channel for allocating radio resources in each frame by changing the sequence or location of the bit sequence embedded in each frame before transmitting the frames. As suggested above, the network infrastructure object can also dynamically allocate various types of control channel elements and their number in a frame.

[0035] In another embodiment, the bit sequence embedded in the sub-frame is used to recognize that the control channel element is intended for the remote unit. In this case, the bit sequence embedded within the sub-frame may be a data-dependent bit sequence, e.g., the CRC sum processed along with the wireless communication device identification information, a code word masked by the wireless communication device identification information, or the like. In this implementation, the first sub-frame, which may be the last sub-frame of the TTI, includes control information including modulation type, resources or antenna mode indicator. Each control channel may be one or more control channel elements, and the size of the control channel may be different in the first and second subframes. The second sub-frame may appear on the same part or on other parts of the control channel than the control information from the first sub-frame. If another portion of the sub-frame is used, the complexity of blind decoding can be reduced by having control channel elements in the second sub-frame known from the location of control channel elements of the remote control channel elements from the first sub-frame.

[0036] In the flowchart 500 of Fig. 5, in step 510, the wireless communication network infrastructure object allocates a portion of the control channel for allocating radio resources in each frame by embedding the bit sequence within the respective frame. The allocated parts of the control channel includes the allocation of all available parts of the control channel or less than all of its available parts, the unallocated part may be used for other purposes, e.g. data transfer. At step 520, the wireless communication network infrastructure object dynamically changes a portion of the control channel for allocating radio resources in each frame, the multiple frames being a radio frame. According to this aspect of the invention, for allocating radio resources, there may potentially be allocated, different in each frame, forming a radio frame part of each control channel. A portion of the control channel for allocating radio resources in each frame can be changed dynamically by changing the location of the bit sequence embedded in each frame, or by using different bit sequences as described above. In step 530, the wireless communication network infrastructure object transmits at least two frames, e.g., a radio frame, each frame comprising a control channel, part of which is allocated for resource allocation.

[0037] Fig. 2, for example, shows the portion of the control channel used to allocate the radio resource depending on where the bit sequence 220 is embedded within the respective frame with respect to the terminating tag or signature. Depending on where the bit sequence is located , a portion of the control channel, e.g., the number of elements used to allocate the radio resource, may be smaller than the entire frame control channel. Generally, different frames forming a radio frame may allocate different portions of respective control channels for assigning a radio resource. In one implementation, the receiver is a wireless communication device enabling receiving a frame corresponding to a transmission time interval, the frame comprising a control channel and a bit sequence embedded in the frame. The coupled controller with the ability to communicate with the receiver is configured to determine the portion of the control channel used to allocate the radio resource based on where the corresponding bit sequence is embedded in the received frame, wherein the portion of the control channel used to allocate the radio resource may be less than entire control channel.

[0038] In a wireless communication device, e.g., one of the remote units 101 or 103 in Fig. 1, the device receives a set of at least two frames, each frame having a control channel having at least two control channel elements, each the frame contains a bit sequence embedded in the frame. In one embodiment, the wireless communications device determines a portion of the control channel used to allocate the radio resource in each frame, based on where the respective bit sequence is embedded within the frame. In general, the portion of the control channel used to allocate the radio resource may be smaller than the entire control channel, and each frame may use different portions of the control channel to allocate the radio resource based on where the respective bit sequence is embedded within the frame.

[0039] In some situations, all control channel elements of the composite control channel transmit control channel information. In this particular implementation, the lack of information about the number of control channel elements, e.g., the bit sequence embedded in the frame, indicates the use of the entire composite control channel to allocate the radio resource. For example, in the absence of control channel number information, the remote unit may assume that the default number of control channel elements is used to allocate radio resources.

[0040] Although the present description of the invention and the optimal ways of using it have been presented with the assumption that it will be understood by a specialist and allow it to be made and used, it is understandable and obvious that there are equivalents to the exemplary embodiments described herein, and that modifications and changes can be made , without departing from the scope of the invention, which is limited not by the embodiments, but by the appended claims.