WO2013173961A1

WO2013173961A1 - Interference randomization

Info

Publication number: WO2013173961A1
Application number: PCT/CN2012/075823
Authority: WO
Inventors: Chunye Wang; Peter Skov; Li Zhang; Xiaoyi Wang; Frank Frederiksen; Lilei Wang
Original assignee: Nokia Siemens Networks Oy
Priority date: 2012-05-21
Filing date: 2012-05-21
Publication date: 2013-11-28

Abstract

The invention relates to an apparatus comprising: at least one processor and at least one memory including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: obtain a shuffling pattern parameter for randomizing physical downlink control channel resources, and signal the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signalling.

Description

INTERFERENCE RANDOMIZATION

Field

The invention relates to apparatuses, methods, systems, computer programs, computer program products and computer-readable media. Background

The following description of background art may include insights, discoveries, understandings or disclosures, or associations together with disclosures not known to the relevant art prior to the present invention but provided by the invention. Some such contributions of the invention may be specifically pointed out below, whereas other such contributions of the invention will be apparent from their context.

In the Long Term Evolution (LTE) or Long Term Evolution Advanced (LTE-Advanced), reuse of resources may cause inter-cell interference at cell border which in turn may cause link degradation. Brief description

According to an aspect of the present invention, there is provided an apparatus comprising: at least one processor and at least one memory including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: obtain a shuffling pattern parameter for randomizing physical downlink control channel resources, and signal the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signalling.

According to an aspect of the present invention, there is provided an apparatus comprising: at least one processor and at least one memory including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: obtain a shuffling pattern parameter, obtain modulated physical downlink control channel symbols, and shuffle the modulated physical downlink control channel symbols by using the shuffling pattern parameter for randomizing physical downlink control channel resources.

According to yet another aspect of the present invention, there is provided a method comprising; obtaining a shuffling pattern parameter for randomizing physical downlink control channel resources, and signalling the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signalling.

According to yet another aspect of the present invention, there is provided a method comprising: obtaining a shuffling pattern parameter, obtaining modulated physical downlink control channel symbols, and shuffling the modulated physical downlink control channel symbols by using the shuffling pattern parameter for randomizing physical downlink control channel resources.

According to yet another aspect of the present invention, there is provided an apparatus comprising: means for obtaining a shuffling pattern parameter for randomizing physical downlink control channel resources, and means for signalling the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signalling.

According to yet another aspect of the present invention, there is provided an apparatus comprising: means for obtaining a shuffling pattern parameter, means for obtaining modulated physical downlink control channel symbols, and means for shuffling the modulated physical downlink control channel symbols by using the shuffling pattern parameter for randomizing physical downlink control channel resources.

According to yet another aspect of the present invention, there is provided a computer program embodied on a computer-readable storage medium, the computer program comprising program code for controlling a process to execute a process, the process comprising: obtaining a shuffling pattern parameter for randomizing physical downlink control channel resources, and signalling the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signalling. According to yet another aspect of the present invention, there is provided a computer program embodied on a computer-readable storage medium, the computer program comprising program code for controlling a process to execute a process, the process comprising: obtaining a shuffling pattern parameter, obtaining modulated physical downlink control channel symbols, and shuffling the modulated physical downlink control channel symbols by using the shuffling pattern parameter for randomizing physical downlink control channel resources.

List of drawings

Some embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which

Figure 1 illustrates an example of a system;

Figure 2 is a flow chart;

Figure 3 is another flow chart;

Figure 4 illustrates examples of apparatuses, and

Figure 5 illustrates other examples of apparatuses.

Description of some embodiments

The following embodiments are only examples. Although the specification may refer to "an", "one", or "some" embodiment(s) in several locations, this does not necessarily mean that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.

Embodiments are applicable to any user device, such as a user terminal, as well as to any network element, relay node, server, node, corresponding component, and/or to any communication system or any combination of different communication systems that support required functionalities. The communication system may be a wireless communication system or a communication system utilizing both fixed networks and wireless networks. The protocols used, the specifications of communication systems, apparatuses, such as servers and user terminals, especially in wireless communication, develop rapidly. Such development may require extra changes to an embodiment. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, embodiments.

In the following, different exemplifying embodiments will be described using, as an example of an access architecture to which the embodiments may be applied, a radio access architecture based on long term evolution advanced (LTE Advanced, LTE-A), that is based on orthogonal frequency multiplexed access (OFDMA) in a downlink and a single-carrier frequency-division multiple access (SC-FDMA) in an uplink, without restricting the embodiments to such an architecture, however. It is obvious for a person skilled in the art that the embodiments may also be applied to other kinds of communications networks having suitable means by adjusting parameters and procedures appropriately. Some examples of other options for suitable systems are the universal mobile telecommunications system (UMTS) radio access network (UTRAN or E-UTRAN), long term evolution (LTE, the same as E-UTRA), wireless local area network (WLAN or WiFi), worldwide interoperability for microwave access (WiMAX), Bluetooth®, personal communications services (PCS), ZigBee®, wideband code division multiple access (WCDMA), systems using ultra-wideband (UWB) technology, sensor networks, mobile ad-hoc networks (MANETs) and Internet Protocol multimedia subsystems (IMS).

In an orthogonal frequency division multiplexing (OFDM) system, the available spectrum is divided into multiple orthogonal sub-carriers. In OFDM systems, the available bandwidth is divided into narrower sub-carriers and data is transmitted in parallel streams. Each OFDM symbol is a linear combination of signals on each of the subcarriers. Further, each OFDM symbol is preceded by a cyclic prefix (CP), which is used to decrease Inter-Symbol Interference. Unlike in OFDM, SC-FDMA subcarriers are not independently modulated.

Typically, a (e)NodeB ("e" stands for evolved) needs to know channel quality of each user device and/or the preferred precoding matrices (and/or other multiple input-multiple output (MIMO) specific feedback information, such as channel quantization) over the allocated sub-bands to schedule transmissions to user devices. Such required information is usually signalled to the (e)NodeB.

Figure 1 depicts examples of simplified system architectures only showing some elements and functional entities, all being logical units, whose implementation may differ from what is shown. The connections shown in Figure 1 are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the system typically comprises also other functions and structures than those shown in Figure 1.

The embodiments are not, however, restricted to the system given as an example but a person skilled in the art may apply the solution to other communication systems provided with necessary properties.

Figure 1 shows a part of a radio access network based on E-UTRA, LTE, LTE-Advanced (LTE-A) or LTE/EPC (EPC = evolved packet core, EPC is enhancement of packet switched technology to cope with faster data rates and growth of Internet protocol traffic). E-UTRA is an air interface of Release 8 (UTRA= UMTS terrestrial radio access, UMTS= universal mobile telecommunications system). Some advantages obtainable by LTE (or E- UTRA) are a possibility to use plug and play devices, and Frequency Division Duplex (FDD) and Time Division Duplex (TDD) in the same platform.

Figure 1 shows user devices 100 and 102 configured to be in a wireless connection on one or more communication channels 104 and 06 in a cell with a (e)NodeB 108 providing the cell. The physical link from a user device to a (e)NodeB is called uplink or reverse link and the physical link from the NodeB to the user device is called downlink or forward link.

The NodeB, or advanced evolved node B (eNodeB, eNB) in LTE- Advanced, is a computing device configured to control the radio resources of communication system it is coupled to. The (e)NodeB may also be referred to as a base station, an access point or any other type of interfacing device including a relay station capable of operating in a wireless environment.

The (e)NodeB includes transceivers, for example. From the transceivers of the (e)NodeB, a connection is provided to an antenna unit that establishes bi-directional radio links to user devices. The antenna unit may comprise a plurality of antennas or antenna elements. The (e)NodeB is further connected to core network 110 (CN). Depending on the system, the counterpart on the CN side can be a serving gateway (S-GW, routing and forwarding user data packets), packet data network gateway (P-GW), for providing connectivity of user devices (UEs) to external packet data networks, or mobile management entity (MME), etc.

A communications system typically comprises more than one (e)NodeB in which case the (e)NodeBs may also be configured to communicate with one another over links, wired or wireless, designed for the purpose. These links may be used for signalling purposes.

The communication system is also able to communicate with other networks, such as a public switched telephone network or the Internet 112. The communication network may also be able to support the usage of cloud services. It should be appreciated that (e)NodeBs or their functionalities may be implemented by using any node, host, server or access point etc. entity suitable for such a usage.

The user device (also called UE, user equipment, user terminal, terminal device, etc.) illustrates one type of an apparatus to which resources on the air interface are allocated and assigned, and thus any feature described herein with a user device may be implemented with a corresponding apparatus, such as a relay node. An example of such a relay node is a layer 3 relay (self-backhauling relay) towards the base station.

The user device typically refers to a portable computing device that includes wireless mobile communication devices operating with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: a mobile station (mobile phone), smartphone, personal digital assistant (PDA), handset, device using a wireless modem (alarm or measurement device, etc.), laptop and/or touch screen computer, tablet, game console, notebook, and multimedia device.

The user device (or in some embodiments a layer 3 relay node) is configured to perform one or more of user equipment functionalities. The user device may also be called a subscriber unit, mobile station, remote terminal, access terminal, user terminal or user equipment (UE) just to mention but a few names or apparatuses.

It should be understood that, in Figure 1 , user devices are depicted to include 2 antennas only for the sake of clarity. The number of reception and/or transmission antennas may naturally vary according to a current implementation.

Further, although the apparatuses have been depicted as single entities, different units, processors and/or memory units (not all shown in Figure 1 ) may be implemented.

It is obvious for a person skilled in the art that the depicted system is only an example of a part of a radio access system and in practise, the system may comprise a plurality of (e)NodeBs, the user device may have an access to a plurality of radio cells and the system may comprise also other apparatuses, such as physical layer relay nodes or other network elements, etc. At least one of the NodeBs or eNodeBs may be a Home(e)nodeB. Additionally, in a geographical area of a radio communication system a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which are large cells, usually having a diameter of up to tens of kilometres, or smaller cells such as micro-, femto- or picocells. The (e)NodeBs of Figure 1 may provide any kind of these cells. A cellular radio system may be implemented as a multilayer network including several kinds of cells. Typically, in multilayer networks, one node B provides one kind of a cell or cells, and thus a plurality of (e) Node Bs are required to provide such a network structure.

Recently for fulfilling the need for improving the deployment and performance of communication systems, the concept of "plug-and-play" {e)Node Bs has been introduced. Typically, a network which is able to use "plug-and-play" (e)Node (e)Bs, includes, in addition to Home (e)Node Bs (H(e)nodeBs), a home node B gateway, or HNB-GW (not shown in Figure 1 ). A HNB Gateway (HNB-GW), which is typically installed within an operator's network may aggregate traffic from a large number of HNBs back to a core network.

LTE or LTE Advanced is designed to support frequency reuse-1 mechanisms to enable a universal frequency reuse pattern providing operators an improved efficiency in spectrum usage. One of system design targets is to increase spectral efficiency and overall signal-to-interference and noise-ratio (SINR). According to frequency reuse-1 , adjacent sites use same frequencies, and different frequency resource users are separated by codes. Thus users at the cell edge are particularly susceptible to interference due to inter-cell interference. Inter-cell radio resource management is used to coordinate resource allocation between different cell sites and to limit the inter-cell interference. Such methods are called inter-cell interference control (ICIC).

Discarding spatial domain schemes, basically two different principles for inter-cell interference control and/or mitigation are provided which both rely on the assumption that unused resources exist in an interfering cell, namely resource coordination and resource randomization.

In the following, a scheme for supporting inter-cell interference randomization for (evolved) physical downlink control channel ((e)PDCCH) is provided.

In the LTE release 8, interference on a legacy PDCCH is randomized across cells so that two PDCCH allocations in two different cells will never use exactly the same set of resource elements. However, this randomization relies on the fact that the PDCCH resources are cell specific and do not support spatial reuse within a cell.

In the following, some embodiments are disclosed in further details in relation to Figures 2 and 3. Some embodiments are especially suitable for randomizing physical downlink control channel resources when spatial reuse within a cell is provided.

One embodiment may be carried out by a device configured to operate as a network apparatus, such as a server, (e)node or host. The embodiment may also be provided as a cloud service. The embodiment starts in block 200 of Figure 2. In block 202, a shuffling pattern parameter for randomizing physical downlink control channel resources is obtained.

The basic principle is that a shuffling pattern parameter controls a shuffling pattern applied to one or more physical resource blocks on (e) PDCCH.

If the shuffling pattern parameter is the same for a plurality of resource blocks, the same shuffling pattern is used for them, and resource coordination is applicable to control inter-cell interference. Resource coordination may include frequency allocation coordination, such as not reusing same frequency in adjacent cells.

On the other hand, if shuffling pattern parameters are different for different resources, different shuffling patterns are used and the randomization effect is achievable providing possibility for non-coordinated frequency reuse between different cells.

In the special case, when a shuffling pattern parameter is a cell identity (cell ID), randomization is provided across different cells.

Typically, a cluster of cells and/or transmission points (TPs) which coordinate interference with each other must use a same shuffling pattern. Usually, the number of cells and/or TPs per a coordination set or group must be a finite number and 3 is a typical value. Additionally, different shuffling patterns must usually be used between coordination sets, in other words, those cells and/or TPs which are not capable to mutual coordination or not configured to carry out it.

The shuffling pattern parameter may be obtained by simulations, for instance. For example, The shuffling pattern parameter may be modulo(celMdentity, 3), e.g. if a cell identity is 1 , 2, 3, 4, 5 or 6, the shuffling pattern parameter is 0, 1 , 2, 0, 1 , or 2, respectively (this example is suitable for a macro cell).

In the 3GPP scenario 4, many TPs share a same cell identity, and thus a node may select any arbitrary number to be used in determining a shuffling pattern parameter. For instance, cell identity ^* 3 + 0 for the first group of TPs and cell identity*3+1 for the second group of TPs, and cell identity*3 + 2 for the last group of TPs, assuming the cell at issue includes 3 TP groups. A node or host may set or update the shuffling pattern parameter for example by taking a suitable value from a memory table.

In block 204, the shuffling pattern parameter is signalled in relation to a cell identity, by using a broadcast channel, or as user device signalling.

A shuffling pattern parameter may be signalled on or for a common control channel. In this case, a user device may access the common control channel and obtain the shuffling pattern parameter for a dedicated control channel.

The shuffling pattern parameter may be signalled to a user device in a plurality of manners. For downlink control information (DCI) on a common control channel, two methods are provided. Namely, a backward compatible way, wherein the shuffling pattern parameter may be signalled as a function of a cell identity, such as mod(CelllD,3), see above, or it may be a cell identity. In a non-backward compatible way, the shuffling pattern parameter may be conveyed by a master information block (MIB) on a broadcast channel (BCH).

For or on a user device's dedicated control channel, the shuffling pattern parameter may be derived by the user device based on signaling from a (e)NB (potentially involving some implicit mapping by the user device). For instance, in the 3GPP scenario 4, one cell comprises a plurality of groups of TPs. Thus all these TP groups share a same cell identity (cell ID). In this case, a (e) NodeB may determine or select a shuffling parameter and a user device may obtain the shuffling parameter from the (e)NodeB. Thus, when the user device monitors a dedicated control DCI, it already has the shuffling parameter available. Another option is that the shuffling pattern parameter may be derived in a manner similar to a demodulation reference signals (D -RS) sequence initializer c_ini_t.

It should be appreciated that the most general case is that each physical resource block has a different shuffling parameter.

It should be appreciated that when capacity is not fully used, typically, the best option is to apply inter-cell interference control (ICIC) as much as possible and then shuffling to randomize interference within the ICIC coordination set or group in question.

The embodiment ends in block 206. The embodiment is repeatable in many ways. One example is shown by arrow 208 in Figure 2.

One embodiment may be carried out by a device configured to operate as a user device. The embodiment starts in block 300 of Figure 3.

In block 302, a shuffling pattern parameter is obtained.

A shuffling pattern parameter may be obtained from a (e)NodeB by means of signalling. For downlink control information (DCI) on or for a common control channel, two methods are provided. Namely, a backward compatible way, wherein the shuffling pattern parameter may be signalled as a function of a cell identity, such as mod(CelllD,3) or it may be a cell identity. In a non- backward compatible way, the shuffling pattern parameter may be conveyed by a master information block (MIB) on a broadcast channel (BCH).

On or for a dedicated control channel, a shuffling pattern parameter may be derived by user device based on signaling from a (e)NB (potentially involving some implicit mapping by the user device). For instance, in the 3GPP scenario 4, one cell comprises a plurality of groups of TPs. Thus all these TP groups share a same ceil identity (cell ID), In this case, a (e) NodeB may determine or select a shuffling parameter and a user device may obtain the shuffling parameter from the (e)NodeB. Thus, when the user device monitors a dedicated control DCI, it already has the shuffling parameter available.

Another option is that the shuffling pattern parameter may be derived similar to a demodulation reference signals (DM-RS) sequence initializer c_ini_t.

In block 304, modulated physical downlink control channel symbols are obtained.

An ePDCCH DCI ("e" stands for "evolved") message is usually encoded with 1/3 convolution coder, repeated or punctured by rate matching and then modulated into quadrature phase shift keying (QPSK) symbols. Thus modulated symbols may be obtained from a processor carrying out modulation, for example. Jn block, 306, the modulated physical downlink control channel symbols are shuffled by using the shuffling pattern parameter for randomizing physical downlink control channel resources.

Before multiplexing modulated ePDCCH symbols, they may be shuffled with modulated symbols of other DCI messages. It should be understood that "other" DCI symbols may be set zeroes especially when capacity is not full used.

The basic principle is that a shuffling pattern parameter controls a shuffling pattern applied for one or more physical resource blocks on (e) PDCCH.

If the shuffling pattern parameter is the same for a plurality of resources blocks, the same shuffling pattern is used for them, and resource coordination is applicable to control inter-cell interference. Resource coordination may include frequency allocation coordination, such as not reusing same frequency in adjacent cells.

On the other hand, if different resources have different shuffling parameters, different shuffling patterns are used and the randomization effect is achievable providing possibility for non-coordinated frequency reuse between difference cells.

In the special case, when a shuffling pattern parameter is a cell identity {cell ID), randomization is provided across different cells.

In the following, an example of shuffling is explained in further detail.

In the example, modulated symbols are represented by NxM matrix A{0,0), A(1 ,0),...A(N,M), wherein N is the number of modulated symbols per a DCI message, such as 36, and M is the maximum number of DCI messaged, the typical value is 4. In the matrix, one column represents one enhanced control channel element eCCE.

If capacity is not fully used, one or more columns may be set zeros. For higher aggregation levels, one DCI may occupy more than one column.

The output of the exemplary shuffling is represented by NxM matrix

B(0,0), 13(1 ,0),..., B(N,M) as B=A(F), wherein F is a shuffling pattern, comprising integers between 1 and the size of the matrix A. In general, F carries out a sorting operation to a sequence. Sorting may be carried out by using a stable sorting algorithm which maintains the relative order of records or values with equal numbers, such as by sorting them in an ascending order. Stable sorting is usually needed, if equal keys exist. For example, keys are X and Y, and X appears before Y in the original list. Then stable sorting always makes X appear before Y in the sorted list. It should be appreciated that when equal elements are indistinguishable, stability of sorting usually plays no role.

In general, if a sequence is sorted, it is reordered in a manner that overrules prior ordering in the case a conflict takes place.

In the example, the sequence to be sorted is marked as C and it is a pseudo-random sequence

n_s, n_prb) + i)*2^Ai , such as n = 0,1 , 143, wherein c(n) is the pseudo-random sequence as defined by TR36.211 section 7.2 ("golden sequence"), initialized with C^_t = X, wherein X denotes a shuffling patter parameter signalled to a user device, 2^Λί denotes 2 to the i power (i being a variable), n_f denotes a system frame number, n_s denotes a slot number within a radio frame, n_prt> denotes the index of a physical resource block, and f(n,n_f, n_s, n_prb) denotes a specific indexing function, an example of which is f(n,n_f, n_s, n_prb) = n * L3 2*L1 + n_f *L2 * L1 + (ns/2) ^* L1 + n_Pr , wherein L1 is the number of PRBs, e.g. 50 for 10MHz system, L2 is the number of sub-frames per radio frame, e.g. 10 and L3 is an arbitrary integer number, e.g. 128.

It should be appreciated that when capacity is not fully used, typically, the best option is to apply inter-cell interference control (ICIC) as much as possible and then shuffling to randomize interference within the ICIC coordination set or group in question. The embodiment ends in block 308. The embodiment is repeatable in many ways. One example is shown by arrow 310 in Figure 3.

The steps/points, signaling messages and related functions described above in Figures 2 and 3 are in no absolute chronological order, and some of the steps/points may be performed simultaneously or in an order differing from the given one. Other functions may also be executed between the steps/points or within the steps/points and other signaling messages sent between the illustrated messages. Some of the steps/points or part of the steps/points can also be left out or replaced by a corresponding step/point or part of the step/point.

It should be understood that conveying, broadcasting, signalling transmitting and/or receiving may herein mean preparing a data conveyance, broadcast, transmission and/or reception, preparing a message to be conveyed, broadcasted, signalled, transmitted and/or received, or physical transmission and/or reception itself, etc. on a case by case basis. The same principle may be applied to terms transmission and reception as well.

An embodiment provides an apparatus which may be any node, host, server, web stick or any other suitable apparatus capable to carry out processes described above in relation to Figure 2.

It should be appreciated that an apparatus may include or otherwise be in communication with a control unit, one or more processors or other entities capable of carrying out operations according to the embodiments described by means of Figure 2. It should be understood that each block of the flowchart of Figure 2 and any combination thereof may be implemented by various means or their combinations, such as hardware, software, firmware, one or more processors and/or circuitry.

Figure 4 illustrates a simplified block diagram of an apparatus according to an embodiment.

As an example of an apparatus according to an embodiment, it is shown apparatus 400, such as a node, including facilities in control unit 404 (including one or more processors, for example) to carry out functions of embodiments according to Figure 2. The facilities may be software, hardware or combinations thereof as described in further detail below.

In Figure 4, block 406 includes parts/units/modules needed for reception and transmission, usually called a radio front end, RF-parts, radio parts, radio head, etc.

Another example of apparatus 400 may include at least one processor 404 and at least one memory 402 including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to: obtain a shuffling pattern parameter for randomizing physical downlink control channel resources, and signal the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signaling.

Yet another example of an apparatus comprises means 404 (406) for obtaining a shuffling pattern parameter for randomizing physical downlink control channel resources, and means 404 (406) for signalling the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signalling

Yet another example of an apparatus comprises an obtaining unit configured to obtain a shuffling pattern parameter for randomizing physical downlink control channel resources, and a signalling unit configured to signal the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signalling.

It should be understood that the apparatuses may include or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and/or reception. This is depicted in Figure 4 as optional block 406.

Although the apparatuses have been depicted as one entity in Figure 6, different modules and memory may be implemented in one or more physical or logical entities.

An embodiment provides an apparatus which may be user device, such as a smart phone or any other suitable apparatus capable to carry out processes described above in relation to Figure 3. It should be appreciated that an apparatus may include or otherwise be in communication with a control unit, one or more processors or other entities capable of carrying out operations according to the embodiments described by means of Figure 3. It should be understood that each block of the flowchart of Figure 3 and any combination thereof may be implemented by various means or their combinations, such as hardware, software, firmware, one or more processors and/or circuitry.

Figure 5 illustrates a simplified block diagram of an apparatus according to an embodiment.

As an example of an apparatus according to an embodiment, it is shown apparatus 500, such as user device or web stick, including facilities in control unit 504 (including one or more processors, for example) to carry out functions of embodiments according to Figure 3. The facilities may be software, hardware or combinations thereof as described in further detail below.

In Figure 5, block 506 includes parts/units/modules needed for reception and transmission, usually called a radio front end, RF-parts, radio parts, radio head, etc.

Another example of apparatus 500 may include at least one processor 504 and at least one memory 502 including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to; obtain a shuffling pattern parameter, obtain modulated physical downlink control channel symbols, and shuffle the modulated physical downlink control channel symbols by using the shuffling pattern parameter for randomizing physical downlink control channel resources.

Yet another example of an apparatus comprises means 504 (506) for obtaining a shuffling pattern parameter, means 504 for obtaining modulated physical downlink control channel symbols, and means 504 for shuffling the modulated physical downlink control channel symbols by using the shuffling pattern parameter for randomizing physical downlink control channel resources. Yet another example of an apparatus comprises an obtaining unit configured to obtain a shuffling pattern parameter and a shuffling unit configured to obtain modulated physical downlink control channel symbols and shuffle the modulated physical downlink control channel symbols by using the shuffling pattern parameter for randomizing physical downlink control channel resources.

It should be understood that the apparatuses may include or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and/or reception. This is depicted in Figure 5 as optional block 506.

Although the apparatuses have been depicted as one entity in Figure 5, different modules and memory may be implemented in one or more physical or logical entities.

An apparatus may in general include at least one processor, controller or a unit designed for carrying out control functions operably coupled to at least one memory unit and to various interfaces. Further, the memory units may include volatile and/or non-volatile memory. The memory unit may store computer program code and/or operating systems, information, data, content or the like for the processor to perform operations according to embodiments. Each of the memory units may be a random access memory, hard drive, etc. The memory units may be at least partly removable and/or detachably operationally coupled to the apparatus. The memory may be of any type suitable for the current technical environment and it may be implemented using any suitable data storage technology, such as semiconductor-based technology, flash memory, magnetic and/or optical memory devices. The memory may be fixed or removable.

The apparatus may be, include or be associated with at least one software application, module, unit or entity configured as arithmetic operation, or as a program (including an added or updated software routine), executed by at least one operation processor. Programs, also called program products or computer programs, including software routines, applets and macros, may be stored in any apparatus-readable data storage medium and they include program instructions to perform particular tasks. Computer programs may be coded by a programming language, which may be a high-level programming language, such as objective-C, C, C++, C#, Java, etc., or a low-level programming language, such as a machine language, or an assembler.

Modifications and configurations required for implementing functionality of an embodiment may be performed as routines, which may be implemented as added or updated software routines, application circuits (ASIC) and/or programmable circuits. Further, software routines may be downloaded into an apparatus. The apparatus, such as a node device, or a corresponding component, may be configured as a computer or a microprocessor, such as single-chip computer element, or as a chipset, including at least a memory for providing storage capacity used for arithmetic operation and an operation processor for executing the arithmetic operation.

Embodiments provide computer programs embodied on a distribution medium, comprising program instructions which, when loaded into electronic apparatuses, constitute the apparatuses as explained above. The distribution medium may be a non-transitory medium.

Other embodiments provide computer programs embodied on a computer readable storage medium, configured to control a processor to perform embodiments of the methods described above. The computer readable storage medium may be a non-transitory medium.

The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, distribution medium, or computer readable medium, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, photoelectrical and/or electrical carrier signal, telecommunications signal, and software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst a number of computers. The computer readable medium or computer readable storage medium may be a non-transitory medium. The techniques described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the apparatus may be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, digitally enhanced circuits, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation may be carried out through modules of at least one chip set (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case it may be communicatively coupled to the processor via various means, as is known in the art. Additionally, the components of systems described herein may be rearranged and/or complimented by additional components in order to facilitate achieving the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.

It will be obvious to a person skilled in the art that, as technology advances, the inventive concept may be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

WHAT IS CLAIMED IS:

. An apparatus comprising:

at least one processor and at least one memory including a computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:

obtain a shuffling pattern parameter for randomizing physical downlink control channel resources, and

signal the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signalling.

2. The apparatus of claim 1 , wherein the shuffling pattern parameter controls a shuffling pattern applied to at least one physical resource block on an evolved physical control channel.

3. The apparatus of claim 1 or 2, wherein each physical resource block has a different shuffling parameter.

4. The apparatus of any preceding claim, wherein the signalling is carried out on or for a common control channel by at least one of the following: as a function of a cell identity, as a cell identity, and by using a master information block on a broadcast channel.

5. The apparatus of any preceding claim, wherein the signalling is carried out on or for a user device's dedicated control channel by using a similar procedure as for a demodulation reference signals sequence initializer

Cirsit-

6. The apparatus of any preceding claim, wherein a cluster of cells and/or transmission points which coordinate interference with each other have a same shuffling pattern and/or cells and/or transmission points which do not coordinate interference with each other have different shuffling patterns.

7. The apparatus of any preceding claim, the apparatus comprising a host, node or server.

8. A computer program comprising program instructions which, when loaded into the apparatus, constitute the modules of any preceding claim 1 to 6. 9. An apparatus comprising:

obtain a shuffling pattern parameter;

obtain modulated physical downlink control channel symbols, and shuffle the modulated physical downlink control channel symbols by using the shuffling pattern parameter for randomizing physical downlink control channel resources.

10. The apparatus of claim 9, wherein the shuffling pattern parameter controls a shuffling pattern applied to at least one physical resource block on an evolved physical control channel used. 11. The apparatus of any claim 9 or 10, wherein each physical resource block has a different shuffling parameter.

12. The apparatus of any preceding claim 9 to 11 , wherein the shuffling pattern parameter is obtained by signalling carried out on or for a common control channel by at least one of the following: as a function of a cell identity, as a cell identity, and by using a master information block on a broadcast channel.

13. The apparatus of any preceding claim 9 to 12, wherein the shuffling pattern parameter is obtained by signalling carried out on or for a user device's dedicated control channel by using a similar procedure as for a demodulation reference signals sequence initializer Cjnit-

14. The apparatus of any preceding claim 9 to 13, wherein the shuffling is carried out by using modulated symbols of other downlink control information messages or by setting symbols zeroes.

15. The apparatus of any preceding claim 9 to 14, the apparatus comprising a user device. 16. A computer program comprising program instructions which, when loaded into the apparatus, constitute the modules of any preceding claim 9 to 15.

17. A method comprising:

obtaining a shuffling pattern parameter for randomizing physical downlink control channel resources, and

signalling the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signalling. 8. The method of claim 7, wherein the shuffling pattern parameter controls a shuffling pattern applied to at least one physical resource block on an evolved physical control channel.

19. The method of claim 17 or 18, wherein each physical resource block has a different shuffling parameter.

20. The method of any preceding claim 17 to 19, wherein the signalling is carried out on or for a common control channel by at least one of the following: as a function of a cell identity, as a cell identity, and by using a master information block on a broadcast channel.

21. The method of any preceding claim 17 to 20, wherein the signalling is carried out on or for a user device's dedicated control channel by using a similar procedure as for a demodulation reference signals sequence initializer c_inj_t.

22. The method of any preceding claim 17 to 21 , wherein a cluster of cells and/or transmission points which coordinate interference with each other have a same shuffling pattern and/or cells and/or transmission points which do not coordinate interference with each other have different shuffling patterns.

23. An apparatus comprising means for carrying out the method according to any one of claims 17 to 22. 24. A method comprising:

obtaining a shuffling pattern parameter;

obtaining modulated physical downlink control channel symbols, and

shuffling the modulated physical downlink control channel symbols by using the shuffling pattern parameter for randomizing physical downlink control channel resources.

25. The method of claim 24, wherein the shuffling pattern parameter controls a shuffling pattern applied to at least one physical resource block on an evolved physical control channel used.

26. The method of any claim 24 or 25, wherein each physical resource block has a different shuffling parameter. 27. The method of any preceding claim 24 to 26, wherein the shuffling pattern parameter is obtained by signalling carried out on or for a common control channel by at least one of the following: as a function of a cell identity, as a cell identity, and by using a master information block on a broadcast channel.

28. The method of any preceding claim 24 to 27, wherein the shuffling pattern parameter is obtained by signalling carried out on or for a user device's dedicated control channel by using a similar procedure as for a demodulation reference signals sequence initializer Ci_ni_t.

29. The method of any preceding claim 24 to 28, wherein the shuffling is carried out by using modulated symbols of other downlink control information messages or by setting symbols zeroes. 30. An apparatus comprising means for carrying out the method according to any one of claims 24 to 29.

31. A computer program embodied on a computer-readable storage medium, the computer program comprising program code for controlling a process to execute a process, the process comprising:

signalling the shuffling pattern parameter in relation to a cell identity, by using a broadcast channel, or as user device signalling.

32. A computer program embodied on a computer-readable storage medium, the computer program comprising program code for controlling a process to execute a process, the process comprising:

obtaining a shuffling pattern parameter;

obtaining modulated physical downlink control channel symbols, and