Description

Embodiments of the present invention related to a SUDAC (Shared User Equipment-Side Distributed Antenna Component), to a user equipment and to a base station. Further embodiments relate to a SUDAC System, to a method for signal forwarding, to methods for transmitting or receiving a signal with a user equipment or with a base station. Further embodiments relate to a computer program. Further embodiments relate to Discovery, Resource Allocation and Communication Protocol for Shared UE-side Distributed Antenna Systems (SUDAS).

Wireless networks aim to increase rates and amounts of data through the networks to allow for more users, more or enhanced services and/or faster transmission times.

Already during their deployment, current 4G mobile communications systems (like LTE-Advanced) appear to suffer from a shortage of data rate that can be provided to the users. It is expected that in the future, the data rate requested by the users grows considerably, which is mainly due to reception of video contents. There is a trend to an increased consumption of non-linear TV/video, i.e., video contents that is not being broadcast at the very moment of its consumption. Besides broadcast contents that is consumed at some later point after its transmission (like the offering of the TV channels' media centers) and that could be stored inside a cache in the user equipment (UE) until its consumption, there is a vast realm of content that cannot simply be distributed by conventional broadcast systems (satellite, terrestrial, cable TV) like YouTube videos. At the same time the contents consumed in the homes requires increasingly high data rate, for instance for Ultra High Definition TV (UHDTV) or 3D contents (with or without dedicated 3D-glasses).

Moreover, people exchange, i.e., down and upload increasingly large files. While this is currently photos of a couple of megabytes, people are going to download complete movies of many gigabytes from their mobile devices in the future. For such actions people are keen to keep the download times as short as possible, such that very high data rates in the order of ten gigabit/s are a realistic requirement for the future. As people are going to use cloud services to a greater extent in the future, there will be a need for fast synchronization of the contents on a mobile device with the cloud when people leave or

enter the coverage of a mobile network, i.e. before they go off-line and after they return from on off-line state. The amount of data to synchronize could be quite

large. All of this shows that transmission at very high data rates may be regarded as a must in the future for many (mobile and stationary) devices.

An alternative to using mobile communications like LTE for downloading such large files is the employment of a local area network (LAN), be it wireless (WLAN, Wi-Fi) or wired (Ethernet). However, the last mile from the backbone network to the homes cannot support the required high data rates in the range of Gbit/s, except if optical fibers are used (fiber-to-the-home FTTH). However, the cost to equip the homes with FTTH is very high; for instance for Germany alone, the cost to equip every building with FTTH is estimated around 93 billion/milliard Euros. Therefore, we reckon that the last mile will eventually become a mainly wireless connection. This reduces the cost for bringing broadband to every building and its rooms significantly.

Moreover, most homes do not possess a dedicated wired LAN infrastructure (Ethernet) to distribute the data received over the last mile further, i.e., most homes employ Wi-Fi to connect their devices to the Internet by their access point (AP), where the AP represents the terminal point of the last mile. It should be observed that for reaching data rates of Gbit/s, either an Ethernet socket or an AP is present in one more or each room of every home or office building. Hence the cost of connecting each room of each building have to be added to the figure mentioned above for connecting the buildings.

Further the main structures of a network topology are centralized (e.g., IEEE802.1 1 ) or distributed (e.g., mobile ad hoc networks such as defined in IEEE802.15, which are also called piconets).

In a centralized architecture only the coordinating device is responsible for discovery and all the data traffic is routed through this device. In a distributed system there also exists peer to peer communication and discovery is supported, which may but not need to be independent of a coordinating device.

The upcoming standard IEEE802.1 1 ad supports, as far as published yet, centralized and distributed structures. The distributed structures are also referred to as adhoc-peer to peer, independent basic service set (IBSS) and/or personal basic service set (PBSS). For discovery 3 low rate physical layer (LRP) channels per 2.16GHz band are used for beacon transmission. Fig. 25 shows a frequency allocation by channel type as it is proposed in the IEEE802.1 1 ad standard. The LRP frequencies are fixed. The discovery is based on beacon data transmissions by the device that wants to be discovered, in [1 ] it is proposed that IEEE802.1 1 b,g,n or IEEE802.1 1 a transmissions may be used to help in scheduling and managing the IEEE802.1 1 ad devices. Directional relaying services are also planned for IEEE802.1 1 ad. These will incorporate decode and forward methods. IEEE802.1 1 networks are using Time Division Duplex (TDD) for transmissions with or without acknowledgement. The initial synchronization on the time structure is done via carrier sense multiple access with collision avoidance (CSMA-CA).

In [2] it is described, how piconets as defined in IEEE802.15 are created and managed. A beacon is presented by the piconet coordinator (PNC) to which further devices in the network synchronize in time and frequency. As asynchronous discovery and communication, typically some implementation of the ALOHA protocol, as it is described in [3] is used. Provided by the PNC is a single framing structure (superframe) that is shared by the whole piconet. Within that a certain period of time is reserved for asynchronous transmissions, all other transmissions are scheduled by the PNC. Methods for dynamically changing the network layout or switching the PNC are defined. Also the scanning of frequency ranges for interference, beacons and channel quality is supported. The PNC decides on the single used frequency in the network (which may change over time to adjust to the interference conditions). Adhoc networks typically do not use the extremely-high frequency (EHF) band as the attenuation of the signals is very high in this frequency range and only line of sight (LOS)-transmissions are possible, wherein [4] provides an extension for mm-waves.

The main challenge for distributed mobile adhoc networks (MANETs) is the solving of the routing problem. For this the received data has to be analyzed and at least the routing relevant information has to be extracted. Adhoc networks are usually very sensitive in the scope of power consumption and they provide sophisticated mechanisms for sleep mode and for how to recover from that while still keeping the network information. There are implementations on localizing the partners in the network to allow the use of beamforming.

For all the realizations discussed above it is common that they are designed to provide a point to point reliability of data transmission. This is ensured by different scheduling and data-acquisition schemes. For example, this may be a common control channel for all devices.

In the state of the art systems frequency, time, code and space are seen as the limited resources that are to be shared and allocated in the best possible way. This is done for one device, be it a real central management unit or a local PNC.

Therefore, there is a need for an improved approach. An objective of the present invention is to provide a SUDAC, a base station, a user equipment, a system or a method enabling high data rates for the downlink, i.e., from a base station to a user equipment, and/or for the uplink, i.e., for a data transmission from the user equipment to the base station, while avoiding the above discussed limitations.

This objective is solved by the subject matter of the independent claims.

Teachings disclosed herein are based on the fundamental idea that data transmission may be optimized by controlling a SUDAC such that transmission of the SUDAC in the direction of the base station or in the direction of the user equipment is enhanced based on a user equipment driven controlling of the SUDAC from a local (user equipment) point of view and/or based on a base station driven controlling. The base station may implement the controlling from a local point of view such that resources of the base station are utilized more efficiently or from a global point of view considering a plurality or all of the components of the SUDAC System (network) such that a use of the resources is optimized within the whole network.

An embodiment provides a SUDAC comprising a first wireless communication interface, a second wireless communication interface and a processor. The first wireless communication interface is configured for using ultra-high frequency in order to establish at least one backend communication link with a base station. The second wireless communication interface is configured for using extremely-high frequency in order to establish at least one frontend communication link with a user equipment. The processor is configured for forwarding a user information signal received via the frontend communication link at least partially (e.g. a payload portion of the user information signal) as a communication signal to be transmitted via the backend communication link while frequency converting the extremely-high frequency to the ultra-high frequency. The processor is further configured for alternatively or additionally forwarding the communication signal received via the backend communication link as the user information signal to be transmitted via the frontend communication link while frequency converting the ultra-high frequency to the extremely-high frequency. The processor is further configured for extracting control information from the user information signal and for controlling forward parameters of the first or the second wireless communication interface based on the control information. The forward parameters relate at least to one of a time, frequency, space or code resource of the backend communication link or the frontend communication link.

The processor is configured for frequency converting the user information signal received at extremely-high frequency to the communication signal at the ultra-high frequency and for frequency converting the communication signal at the extremely-high frequency to the communication signal at the ultra-high frequency. Alternatively or in addition the SUDAC comprises an analog to digital converter configured for digitizing the user information signal received at extremely-high frequency, and a digital to analog converter configured for analogizing a digitalized communication signal to obtain the communication signal at the ultra-high frequency wherein the processor is configured for generating the digitalized communication signal based on the digitalized user information signal.

When the processor is configured for frequency converting the user information signal received at extremely-high frequency to the communication signal at the ultra-high frequency and for frequency converting the communication signal at the extremely-high frequency to the communication signal at the ultra-high frequency, a payload portion of the communication signal or the user information signal may be forwarded in a purely analog way. This may allow for an implementation of the SUDAC without analog-digital and digital-analog converters for receiving and transmitting the user information signal and/or the communication signal. Such SUDACs may be also referred to as analog SUDACs (aSUDAC).

A forwarding based on frequency conversion without digitizing the signals allows for low-cost SUDACs and for a reduced time delay as time consuming data processing may be skipped. An implementation of the SUDAC in which the SUDAC comprises the analog to digital converter configured for digitizing the user information signal and further comprises a digital to analog converter configured for analogizing the digitalized communication signal (referred to as digital SUDAC - dSUDAC) allows for flexible filtering of the signal e.g. for interference or out of band noise reduction but also can be used for modifying the signal during the forwarding process, e.g., by adding or removing information, changing a modulation type etc. The control information may be received from a user equipment such as a laptop, a PC, a mobile phone or the like or may be received from a base station.

According to a further embodiment, a user equipment is provided comprising a first wireless communication interface and a second wireless communication interface. The first wireless communication interface is configured for using ultra-high frequency in order to establish at least one direct communication link with a base station. The second wireless communication interface is configured for using extremely-high frequency in

order to establish at least one frontend communication link with a SUDAC. The user equipment is configured for receiving a user signal partially via the direct communication link and at least partially via the frontend communication link. The user equipment is associated to the base station (e.g., the base station may be a service provider of the user equipment) and configured for generating the user information signal based on an information received from a further user equipment associated to a further base station such that the user information signal comprises information related to the user equipment and information related to the further user equipment.

This allows for the advantage that the user equipment may provide the further user equipment a so called piggyback mode such that the further user equipment may transmit data to the SUDAC and/or to the base station without maintaining an own communication link to the SUDAC or to the base station. Further, a SUDAC that is exclusively controlled (used) by a base station or the user equipment may be used as data forwarding apparatus (relay) without controlling it. By inserting the information of the further user equipment into the message or the signal generated by the user equipment, an overhead of a message of the further user information may be avoided such that resource utilization in the network in terms of increasing amount of payload data transferred within the network is enhanced.

According to further embodiments, a base station is provided. The base station comprises a plurality of wireless communication interfaces and a controller configured for controlling the plurality of wireless communication interfaces such that a multiple antenna function, e.g., a multiple input multiple output function or a beamforming function, of the plurality of wireless communication interfaces is obtained. The base station is configured for receiving control information via at least one of the plurality of wireless communication interfaces, the control information related to a SUDAC or an user equipment communicating with the base station. The controller is configured for adapting transmission characteristics of the multiple antenna function based on the control information.

This allows for the advantage that a base station operating mode may be adjusted based on information and/or commands from the SUDAC and/or from the user equipment. Further, information may be provided to the base station by the SUDAC and/or the user equipment, the information indicating that the base station is requested to organize or reorganize the network. Both options allow for an increase in network efficiency in terms of resource allocation.

According to a further embodiment, a SUDAC System (SUDAS) is provided. The SUDAC System comprises a SUDAC, a base station and a user equipment.

According to further embodiments, methods for signal forwarding and for transmitting or receiving a signal with a user equipment or with a base station are provided.

According to a further embodiment, a computer program for those methods is provided.

Embodiments of the present invention will subsequently be discussed referring to the enclosed drawings, wherein:

Fig. 1 a schematic block diagram of a SUDAC which is a shared user equipment-side distributed antenna component according to an embodiment;

Fig. 2 a schematic block diagram of a SUDAC being modified when compared to the

SUDAC shown in Fig. 1 and comprising two filters according to an embodiment;

Fig. 3a a schematic block diagram of the user equipment maintaining a direct

communication link to a base station and a frontend communication link to the SUDAC according to an embodiment;

Fig. 3b a schematic block diagram in which the SUDAC is configured for establishing a first backend communication link to a base station and a second backend communication link to a further base station;

Fig. 4 a schematic block diagram of the base station configured for communicating with the SUDAC via the backend communication link and to the user equipment via the direct communication link according to an embodiment;

Fig. 5 a schematic block diagram of a SUDAC system according to an embodiment;

Fig. 6 a schematic block diagram of a SUDAC system comprising two user equipment devices, the SUDAC and two base stations according to an embodiment;

Fig. 7 a schematic diagram of a SUDAC system comprising the user equipment, three

SUDACs arranged at different locations, wherein a line of sight between two SUDACs is prevented by a wall according to an embodiment;

Fig. 8 a schematic diagram of a SUDAC system that is modified when compared to the SUDAC system of Fig. 7 according to an embodiment;

Fig. 9 a schematic block diagram of a SUDAC system comprising a first and a second

BS-side-SUDAC configured for establishing an inter-backend communication link with the base station using the extremely-high frequency;

Fig. 10 a schematic block diagram of a SUDAC system comprising two user equipment and two SUDACs, wherein a backend communication link from a SUDAC to the base station is inactive;

Fig. 1 1 a communication between the user equipment and the SUDAC and in particular a payload and status-control channel association according to an embodiment;

Fig. 2 a schematic structure of a plurality of rendezvous-channels that may be

implemented in the extremely-high frequency in communication links between a SUDAC and a user equipment according to an embodiment;

Fig. 13 a schematic diagram of a SUDAC system comprising the SUDAC, two user equipment devices as well as two base stations according to an embodiment;

Fig. 14a an illustration of an association of the user equipment and the control/status channel of the SUDAC according to an embodiment;

Fig. 4b an illustration of a retransmission of the SUDAC in which the loopback response is inserted between two pilot symbols according to an embodiment;

Fig. 15a the conversion of the frontend communication link to the backend

communication link in an upload direction according to an embodiment;

Fig. 15b a conversion of the SUDAC in a downlink direction according to an

embodiment;

Fig. 16a a situation modified when compared to the Figs. 13a and 13b according to an embodiment, wherein a bandwidth for payload is larger;

Fig. 16b a situation according to Fig. 16a in which the transmission direction is swapped;

Figs. 17a-d a comparison between a normal allocation and a piggyback allocation of a transmission media according to an embodiment;

Fig. 18 a usage of synchronization symbols which are embedded in the status/control channel according to an embodiment;

Fig. 19 different types of sections of the signaling data of the status/control channel according to an embodiment;

Fig. 20a a schematic implementation of filters of the SUDAC according to an

embodiment;

Fig. 20b a realization of a filtering with two filters each attenuating frequencies outside the respective payload channel according to an embodiment;

Fig. 21 a schematic overview of a frequency allocation in the ultra-high frequency in case of LTE in Germany;

Fig. 22 a schematic flowchart of a method for signal forwarding according to an

embodiment;

Fig. 23 a schematic flowchart of a method for transmitting or receiving a signal with a user equipment according to an embodiment;

Fig. 24 a schematic flowchart of a method for transmitting or receiving a signal with a base station according to an embodiment; and

Fig. 25 a frequency allocation by channel type as it is proposed in the IEEE802.11 ad standard according to prior art.

Below, embodiments of the present invention will be discussed in detail, wherein identical reference numbers are provided to objects having identical or similar functions, so that the description thereof is interchangeable or mutually applicable.

In the following, reference will be made to ultra-high frequencies and extremely-high frequencies. Ultra-high frequencies relate to frequencies in a range from at least 300 MH to 6 GHz. Extremely-high frequency relates to frequencies in a range from at least 30 GHz up to 300 GHz and preferably to the so called 60 GHz band utilizing frequencies in the range between 57 and 64 GHz. Ultra-high frequencies are used, for example, in mobile communication networks such as for GSM and/or LTE (Long Term Evolution) and is suitable for transferring data to or from a mobile device and from other mobile devices or a base station. Other frequency bands such as the extremely-high frequency band provide higher bandwidth but waves transmitted at such frequencies (so called millimeter-waves) suffer from high attenuation such that a line-of-sight (LOS) connection is preferred between communication partners to allow for reliable data transfer.

In the following, the term beacon relates to a control channel in the EHF band hosting information about SUDAS, its configuration, and reference data (= pilots). The term payload relates to relayed signal via SUDAS from BS to UE or vice versa. The term frontend relates to a communication in the EHF (approximately 60 GHz) band and the term backend relates to a communication in the s6G (sub 6 GHz, i.e., below 6 GHz) band.

In the following, reference will first be made to SUDACs (Shared User Equipment-Side Distributed Antenna Components) according to embodiments. The SUDACs may be regarded, when expressed simplified, as a signal repeating device configured for transmitting data signals on the ultra-high frequency and/or on the extremely-high frequency while retransmitting a received data signal and/or while frequency converting signals from one frequency range to another and vice versa. Afterwards, reference will be made to a user equipment according to a further embodiment. Afterwards, reference will be made to a base station according to a further embodiment before a SUDAC System comprising a SUDAC, a user equipment and a base station according to embodiments is described.

Fig. 1 shows a schematic block diagram of a SUDAC 10 which is a shared user equipment-side distributed antenna component, i.e., an apparatus for forwarding signals while frequency converting the signals. The SUDAC 10 comprises a first wireless communication interface 12 which is configured for using ultra-high frequency to establish at least one backend communication link 14 with a base station 40 by transmitting the communication signal 42a to be received from the base station 40 and by receiving the communication signal 42b from the base station 40. The backend communication link 14 may be a unidirectional data link from the base station 40 to the SUDAC 10 (downlink) or from the SUDAC 10 to the base station 40 (uplink). Alternatively, the backend communication link 14 may be a bidirectional data link implementing both, the uplink and the downlink.

The SUDAC 10 comprises a second wireless communication interface 16 which is configured for using extremely-high frequency to establish at least one frontend communication link 18 with a user equipment 30 by transmitting the user information signal 32a to be received from the user equipment 30 and by receiving the user information signal 32b from the user equipment 30. As it was described for the backend communication link 14 the frontend communication link 18 may be a unidirectional (uplink or downlink) or a bidirectional link.

The SUDAC 10 comprises a processor 22 which is configured for at least partially forwarding a user information signal 32b received via the frontend communication link 18 as at least a part of a communication signal 42a which is to be converted and to be transmitted via the backend communication link 14. The processor 22 is configured for frequency converting the extremely-high frequency implemented in the frontend communication link 18 to the ultra-high frequency implemented in the backend communication link 14 and for at least partially transmitting the communication signal 42a based on the user information signal 32b. The conversion may be based, for example, on a reception of a signal and based on a generation of a new signal. Alternatively or in addition, the received signal may be converted based on a demodulation and a modulation of the received signal to a different carrier. The user equipment may exchange information with the base station partially (and partially via the direct communication link 34) or completely (i.e., no direct communication link 34 is established) via the frontend communication link 18 and the backend communication link 14. The received user information signal 32b may comprise a portion (payload) to be forwarded to the base station 40 and control information 24.

The SUDAC 10 may be a stand-alone device. Alternatively, the SUDAC 10 may be integrated into other devices such as (light-) switches, plug sockets in buildings, devices in cars or the like. The SUDAC 10 may also be part of a further wireless communication device such as a mobile phone, a router or the like. The SUDAC 10 may establish backend communication links 14 to more than one base station and/or a plurality of backend communication links 14 to the base station 40 at a time. Alternatively or in addition the SUDAC 10 may also establish more than one frontend communication links 18 to the user equipment 30 and/or frontend communication links 18 to more than user equipment.

The SUDAC 10 may be configured to transmit the communication signal 42a based on the payload and without the control information 24 or with (possibly different or changed) control information 24. Alternatively or in addition the received communication signal 42b comprises the payload and optionally the control information 24. The SUDAC 10 may be configured to transmit the user information signal 32a based on the payload and based on a generated or modified control information 24. In simple words, the control information 24 may be transmitted (unidirectional or bidirectional) as a point to point information between the user equipment 30 and the SUDAC 10 and/or between the SUDAC 10 and the base station 40. The payload may be forwarded from the base station 40 to the user equipment 30 via the SUDAC 0 or vice versa.

By this an indirect data link may be implemented between the user equipment 30 and the base station 40 via the SUDAC 10 which is from the point of view of the user equipment 30 an uplink connection.

The processor 22 is further configured for forwarding the communication signal 42b received via the backend communication link 14 as the user information signal 32a which is to be transmitted via the frontend communication link 18. The processor 22 is configured for frequency converting the ultra-high frequency to the extremely-high frequency. This allows for a further indirect data communication link between the user equipment 30 and the base station 40 which is, from the point of view of the user equipment 30 a downlink connection. The processor 22 may further be configured for applying further processing to the signal such as decoding and/or encoding.

The processor 22 is configured for extracting control information 24 from the user information signal 32b and/or from the communication signal 42b and for controlling forward parameters of the first or the second wireless communication interface 12 or 16 based on the control information 24. Alternatively or in addition, the processor may also be configured for combining the control information 24 with the signal to be transmitted or forwarded. For example, the portion of the communication signal 42b to be forwarded may be combined with the control information 24 such that the user information signal 32a comprises the portion of the communication signal (payload) and the control information.

The control information 24 may be received via the user information signal 32b, for example, when being incorporated into a header or a predetermined part of the user information signal 32b. Alternatively, or in addition, the SUDAC 10 may also be configured for receiving and extracting control information from the communication signal 32b. The control information 24 may be, for example, a transmit power, a modulation scheme and/or a parameter related to a resource utilized by the SUDAC 10. The SUDAC 10 may be implemented to utilize transmission media in terms of a time division duplex (TDD), a frequency division duplex (FDD) and/or a space division duplex (SDD). Thus, the control information 24 may be related to a frequency, a code, a space and/or a time slot (resource) to be utilized by the SUDAC 10, in particular by the wireless communication interfaces 2 and/or 16.

The processor 22 may be configure for a frequency converting the user information signal 32b to the communication signal 42a and for frequency converting the communication signal 32b to the communication signal 32a.

Alternatively or in addition and as it will be described with reference to Fig. 2, the SUDAC 10 may comprise analog to digital converters (ADC) and digital to analog converters (DAC) which allow for digitizing a received signal 32b or 42b, for processing, evaluating and/or manipulating (modifying) the digitized signal and afterwards for analogizing and transmitting the signal. This allows for a high flexibility with respect to resource utilization as the user information signal 32a and/or the communication signal 42a may be adapted (modified) such that utilization of the restricted resources is enhanced. A SUDAC comprising a digital frontend comprising the ADCs and DACs may be referred to as a digital SUDAC (dSUDAC).

If the SUDAC 10 is realized without the above mentioned ADCs and DACs the SUDAC 10 may implement the frequency converting and signal forwarding in an analog way and may thus be referred to as an analog SUDAC (aSUDAC).

The SUDAC 10 may comprise filters for filtering received and/or transmitted signals 32a, 32b 42a and/or 42b. The filters may be implemented as digital filters or as analog filters. An analog filter may be implemented partially implicitly in the mixer stages and the used antennas of the wireless communication interfaces. In case of frequency separation between payload and status/control channels, the control information 24 may be extracted by a narrowband filter. The SUDAC may comprise a (narrowband) ADC for digitalizing the extracted control information 24 such that the control information may be evaluated by the SUDAC 10. Further, the SUDAC 10 may comprise a (narrowband) DAC for analogizing the control information that may be transmitted.

The frontend communication link 18 and the backend communication link 14 together form a so called relay link which is a supporting link supporting communication between the user equipment 30 and the base station 40 which may maintain a direct communication link 34. The direct communication link 34 may be a regular mobile communication link, for example, between a mobile phone and a base station, when the user equipment 30 is a mobile phone. The user equipment 30 may be any mobile or immobile device configured

for communication in a mobile communication network. For example, the user equipment 30 may be a laptop, a mobile phone, in particular, a so called smartphone, a tablet computer, a PC, a television device and/or a radio device.

The base station 40 is configured for providing services like data communication to the user equipment 30 and may be, for example, a transmitting mast comprising a plurality of transmitting antennas. Alternatively, the base station 40 may be implemented as a plurality of transmitting masts each comprising at least one transmitting antenna and be controlled to implement one virtual base station utilizing the plurality of transmitting masts. The several transmitting masts may form a base station network group, i.e., different transmitting nodes of a service provider. Thus, the base station 40 may implement a multi antenna function (Multiple Input Multiple Output - MIMO), for example, a beamforming function to enhance transmission quality along a beam direction and/or a spatial multiplexing function, i.e., each wireless communication interface (antenna) is configured for transmitting an independent signal, utilization of antenna diversity and/or a space-time-coding function, i.e., to transmit subsequent symbols signals are transmitted by the wireless communication interfaces, wherein the signals are related to each other based on a code utilized. This allows for maintaining a plurality or even a multitude of communication links to a plurality or a multitude of other devices. Thus, the SUDAC may be integrated into a mobile communication network as a virtual antenna of the user equipment 30 and/or of further user equipment. This allows for the base station 40 adapting its communication to the user equipment 30 in order to utilize the "regular" antenna of the user equipment 30 and the further (virtual) antenna such that the connection between the user equipment 30 and the base station 40 is enhanced. Alternatively, the communication between the user equipment 30 and the base station 40 may completely be provided via the relay link, e.g., when the direct communication link 34 is lost, for example, inside a building.

The user equipment 30 may utilize the SUDAC 10 as an external antenna, i.e., the user equipment 30 controls the SUDAC and may inform the base station 40 about its external antenna. According to one embodiment, the SUDAC 10 may only be controlled by one user equipment at a time. According to another embodiment, a further user equipment may request to control the SUDAC 10, wherein the SUDAC 10 is configured for sharing its capabilities among the user equipment devices requesting to control the SUDAC. For example, at a first time the SUDAC may be utilized by a first user equipment and at another time the SUDAC may be utilized by a further user equipment. Alternatively, or in addition, the frequency, the space or the code domain may be shared amongst the user equipment.

The SUDAC 10 utilizing the extremely-high frequency at the frontend communication link 18 allows for a plurality of frontend communication links to enhance communication of a plurality of user equipment. Thus, the SUDAC 10 may be configured for maintaining a plurality of frontend communication links to a plurality of user equipment and/or to maintain a plurality of backend communication links 14 to a plurality of base stations, wherein different base stations or base station network group. Different base stations or base station network groups may be related to different network providers, i.e., the SUDAC 10 may be configured for communicate to base stations or base station network groups of different providers and for forwarding respective data signals.

Fig. 2 shows a schematic block diagram of a SUDAC 10' being modified when compared to the SUDAC 10 and comprising a digital filter 25a and a filter 25b. The filter 25a and/or 25b may be implemented, for example as a field programmable gate array (FPGA), as a digital signal processor (DSP), a microcontroller or the like. The filter 25a is configured for filtering the user information signal 32b. The filter 25b is configured for filtering the communication signal 42b. The SUDAC 10' comprises an ADC 26a for digitalizing the filtered user information signal 32b to obtain a digitalized version thereof. The SUDAC 10' comprises an ADC 26b for digitalizing the filtered communication signal 42b. Further the SUDAC 10' comprises a DAC 28a and a DAC 28b, wherein the DAC 28a is configured for analogizing a signal obtained from the processor 22' and based on the signal digitalized by the ADC 26b. Thus, the processor 22' may be configured for modifying the digitalized version of the communication signal 42b. The DAC is configured for analogizing the signal obtained from the ADC 26a which is processed by the processor 22'. The modification of the digitalized version of the communication signal 42b and/or of the user information signal 32b may comprise an insertion or an extraction of a signal that was received indirectly from a further user equipment via the user equipment 30, e.g., by using a so called piggyback function which is described below. In simple words, the user equipment 30 may be utilized as a relay by the further user equipment. Multiple user equipment may build a SUDA System (SUDAS).

The filters 25a and 25b may be implemented as analog or digital frequency adaptive preselector filters and allow for suppressing interferences. The interferences may result from other communication partners communicating in the same frequency range and/or from the SUDAC itself when it comprises further wireless communication interfaces for maintaining further frontend communication links and/or backend communication links.

Alternatively, the backend communication links and/or the frontend communication links may be implemented such that the frequency range of the respective link is divided, i.e., partitioned by filtering such that interference between partitioned portions of the frequency range is reduced or minimized. When the filters 25a and/or 25b comprise digital filters, this allows for a time variant filtering at low costs and low space requirements.

The SUDAC 10' is a so called dSUDAC comprising the ADCs 26a and 26b and the DACs 28a and 28b (digital frontend). The digital processing of the user information signal 32b and/or the communication signal 42b allows for an inclusion of the control information 24 depicted in Fig. 1 in a payload channel, i.e., the control information may be transmitted via the same frequency as the data to be forwarded, i.e., the control information may be included into the payload channel in a different time (t)/frequency (f)-resource block. The processor 22 may be configured for analyzing the control information 24 in the digital domain. In contrast, an analog SUDAC may forward the signals such that the payload channel is transferred in a purely analog way without using analog-digital and digital-analog converters.

In other words, a major difference between aSUDACs and dSUDACs is that the payload bandwidth of dSUDAC can be handled more flexibly as the filtering of the signal can be done in the digital domain. This basically means that filter coefficients are exchanged while an aSUDAC needs to physically switch between different filter implementations. Further, a dSUDAC may aggregate different carriers by changing the carrier frequency distances. A dSUDAC may synchronize to a common network clock. This allows the dSUDAC to apply a phase shift to the payload which allows to provide a kind of beamforming by using two SUDACs in which at least one is a dSUDAC. This means that both SUDACs receive the same payload signal on the ultra-high frequency (e.g. below 6 GHz) and transmits it on the same extremely-high frequency (e.g. in the range of 60 GHz ) frequency. By applying the correct phase shift both signals will constructively interfere. Further, a dSUDAC may change the payload data transmission mode from TDD to FDD and vice versa. A dSUDAC may provide the same discovery and acquisition methods on the backend communication link as on the frontend communication link. A dSUDAC may provide compress and forward methods and decode and forward methods for frontend and backend link signals.

For example when the processor 22' is configured for compress and forward a received user information signal 32b, a compression rate applied to obtain the communication signal 42a may be varied by the processor 22' dependent on a rate of overhead included, for example, based on further or redundant information due to channel estimation and interference avoidance.

Fig. 3 shows a schematic block diagram of the user equipment 30 maintaining the direct communication link 34 to the base station 40 and the frontend communication link 18 to the SUDAC 10 or alternatively to the SUDAC 10'. The user equipment 30 comprises a processor 31 configured for signal processing. The user equipment 30 comprises a first wireless communication interface 36 which is configured for using the ultra-high frequency to establish the direct communication link 34. The user equipment 30 further comprises a second wireless communication interface 37 which is configured for using the extremely-high frequency to establish the frontend communication link 18. The user equipment 30 is configured for receiving a user signal, for example, data to be downloaded, partially via the direct communication link 34 and at least partially via the frontend communication link 8. As stated above, the SUDAC 10 may be utilized as a further wireless communication interface such as a spaced antenna of the user equipment 30. Thus, data of the base station 40 to be transmitted to the user equipment 30 may be partially transmitted via the direct communication link 34 and at least partially or even completely via the frontend communication link 18 which means that the SUDAC 10 receives the communication signal 42b and forwards the user signal in form of the user information signal 32b via the frontend communication link 18. The user equipment 30 is associated to the base station 40. For example, the base station 40 is operated by a service provider that provides services to the user equipment 30 as it is known from mobile telecommunication or data service providers.

The user equipment 30 is configured for receiving a signal 38 via a direct communication from a further user equipment 39 which also requests to send data to the base station 40 or another base station. For example, the user equipment 39 is unable to maintain a direct communication link to a base station it is associated to and/or it requests also an enhancement of communication by the SUDAC 10. When the SUDAC 10 is utilized, i.e., controlled, by the user equipment 30 the SUDAC 10 may be unable or may deny to be controlled by the user equipment 39 and to implement communication enhancement as it is requested by the user equipment 39. Therefore, the user equipment 39 may transmit the data signal 38 via a direct communication link to the user equipment 30 which may forward it at least partially to the SUDAC 10. Alternatively, the frontend communication link 18 may comprise a random access channel, i.e., parts of the resources utilized may be open to be utilized by third parties such as the user equipment 39. When the SUDAC 10 receives a data signal 38 transmitted by the user equipment 39 utilizing the random access channel, the SUDAC 10 may simply retransmit the data signal 38 as the data

signal 38' (user information signal) such that the user equipment 30 receives data from the user equipment 39 by the (indirect) link via the SUDAC 10. The user equipment 30 is configured for generating the user information signal 32a based on data the user equipment 30 wants (requests) to transmit (upload data) and based on information received from the further user equipment 39.

This allows for a so called piggyback mode in which the user equipment 30 includes or combines the information received from the user equipment 39 to or with its own information and transmits both information to the SUDAC 10. This may also be regarded as a communication mode of the further user equipment 39. The SUDAC 10 may either transmit the piggyback information to the base station 40 or to a further base station 41. The base station 40 may be configured for separating the information from the user equipment 30 which is associated to the base station 40 from the information of the user equipment 39 which may be associated to the base station 40 or to the further base station 41. In the latter case, the base station 40 may be configured for transmitting the information from the further user equipment 39 to the further base station 41 , i.e., the base station 40 is configured for receiving information (e.g., in a payload channel) related to the user equipment 30 via the backend communication link and via the SUDAC 10. The user equipment may be related to the base station. The SUDAC may transmit the information as a piggyback information piggybacked to the information. Alternatively or in addition the user equipment 30 may be configured for utilizing more than one carriers, i.e., to establish more than one frontend communication links and/or direct communication links. The piggyback function may then be implemented such that the further information is related to a further communication link to be piggybacked by another communication link of the user equipment 30. A single frontend communication link may comprise a plurality or even a multitude of carriers that may be separated and/or aggregated by an aSUDAC. In case of a dSUDAC a "broad" communication link may be realized comprising all the information and to be separated and/or aggregated by the dSUDAC such that a single frontend communication link may be mapped to a plurality or multitude of backend communication links and/or vice versa.

This allows for communication of user equipment devices to base stations even if they do not maintain a direct communication link to their base station and/or to reduce data overhead in terms of control information. In the piggyback mode, both information related to the user equipment 30 and to the user equipment 39 may be included into one payload channel which is associated to respective control channels configured for comprising control information. This means that for transmitting the information of the further user equipment an allocation of further control channels may be avoided such that the

respective resources that would have been utilized may be saved and used for other services.

Alternatively or in addition, the SUDAC 10 may be configured for establishing a direct communication link (i.e., a further frontend communication link) to the further user equipment 39. By this information related to the further user information may be received via the SUDAC 10. The SUDAC 10 may then be configured for generating the communication signal 42 based on the information related to the user equipment 30 and based on the information related to the further user equipment 39 by piggybacking the information related to the further user equipment to the information related to the user equipment 30.

Fig. 3b shows a schematic block diagram in which the first wireless communication interface 12 of the SUDAC 10 is configured for establishing a first backend communication link 14a to the base station 40 and a second backend communication link 14b to the further base station 41 . The SUDAC 10 is configured for establishing both backend communication links 14a and 14b at the ultra-high frequency. The first wireless communication interface 12 may be realized as a plurality of wireless communication interfaces, each configured for communicating with a base station 40 or 41. Alternatively the first wireless communication interface 12 may be implemented as one interface configured for transmitting in a broad frequency range such that communication with both base stations 40 and 41 is enabled, the base stations transmitting in different frequency ranges, e.g., as utilizing frequency bands associated to different service providers as described in Fig. 21.

The SUDAC 10 is configured for receiving a user information signal 32b from the user equipment 30 via the frontend communication link 18. The user information signal 32b comprises information related to the user equipment 30 and a further information related to the user further equipment 39, i.e., the user equipment 30 transmits the information related to the further user equipment 39 by using the piggyback option. The information related to the further user equipment 39 is also related to the further base station 41. For example, the further information may comprise an information indicating that the further base station 41 is a designated receiver of the information.

The SUDAC 10 is configured for forming a communication signal 42a-1 to be transmitted via the first backend communication link 14a and comprising the information related to the user equipment 30 and for forming a communication signal 42a-2 to be transmitted via the second backend communication link 14b and comprising the information related to the

further user equipment 39. In simple words, the SUDAC 10 is configured for separating both information and for transmitting them separately.

Fig. 4 shows a schematic block diagram of the base station 40 configured for communicating with the SUDAC 10 via the backend communication link 14 and to the user equipment 30 via the direct communication link 34. The base station 40 comprises three wireless communication interfaces 44a, 44b and 44c and a controller 46 configured for controlling the wireless communication interfaces 44a-c such that a multiple antenna function, for example, a spatial multiplexing, a space-time-coding and/or a beamforming function of the wireless communication interfaces 44a-c is obtained. For obtaining a M I MO-f unction, the controller 46 may be configured for controlling each of the wireless communication interfaces 44a-c such that one or more of them maintain a direct link to a communication partner, e.g., a user equipment or a SUDAC. This is called a so called single-antenna mode, wherein the base station 40 may be configured to implement a plurality of single-antenna modes at a time to different communication partners. The controller may be configured for precoding the signals to be transmitted such that each signal to be transmitted to other communication partners is transmitted via all of the used wireless communication interfaces (antennas) to obtain a so-called spatial stream. Alternatively or in addition the controller 46 may be configured for controlling one or more of the wireless communication interfaces 46a-c such that the respective wireless communication interfaces 44a-c implement a beamforming function, e.g., by transmitting the same signal with a phase shift that corresponds or is related to a distance of the utilized interfaces (antennas) such that constructive and destructive interference may occur and/or a so called beam with a good signal quality along a beam direction is obtained.

The base station 40 is configured for receiving control information via the direct communication link 34 from the user equipment 30, e.g., as part of the control information for controlling and/or signaling communication parameters. The controller 46 is configured for adapting the transmission characteristics of the multiple antenna function based on the control information. The control information may include an identifier of a SUDAC which is utilized by the user equipment 30 or a request directed to the base station 40 indicating to establish the backend communication link 14. The request may be based, for example, on a signal quality information. Simplified, the user equipment 30 may select one or more SUDACs to which it may communicate allowing a good channel quality and send information related to the selected SUDACs to the base station 40. Alternatively or in addition, the control information may comprise information related to a location of the selected SUDACs such that the base station 40 adjusts the direction of one or more

beams to a direction in which the one or more SUDACs is located with respect to the base station 40.

Alternatively or in addition, the control information may be transmitted by the SUDAC 10. Thus, operation of the base station 40 is at least partially controllable by the user equipment 30 and/or the SUDAC 10. This allows for a more efficient usage of the media accessed by the base station 40, as the other communication partners may control the base station 40 such that it utilizes the media efficiently with respect to the network.

The control information may comprise geographic information related to the user equipment 30 and/or to the SUDAC 10 or other communication partner such that a directional radio pattern of a signal transmitted by the base station may be modified. Especially, when the base station is formed by several transmitting masts spaced by large distances, the directional radio pattern may not be a beam, but resulting in a constructive interference at a position or area indicated by the geographic information. A beamforming in terms of a plurality of wireless interfaces being arranged at basically one position may lead to an adaptation of a preferred direction of the backend communication link 14 wherein the preferred direction may be directed towards the SUDAC 10. Alternatively, also the preferred direction of the direct communication link 34 may be adapted, i.e., the beam or the area may be directed towards or adjacent to the user equipment 30 and/or the positive interference may be effective at a location of the user equipment 30. Alternatively or in addition the control information may also relate to a bandwidth information such that the controller 46 may be configured to modify or adapt a bandwidth of the direct communication link 34 and/or of the backend communication link 14 based on the control information.

Alternatively or in addition, the control information may also refer to a resource allocation (time frequency, code and/or space) that is requested by the user equipment 30 and/or by the SUDAC 10. The base station 40 may be configured to respond to that information, e.g., to acknowledge a new allocation scheme and to adapt the current resource allocation.

The base station 40 may be configured to communicate to a plurality of user equipment devices and/or to a plurality of SUDACs. In such a case, the base station 40 may be a or the network node having almost or all information with respect to the communication partners within the network especially when SUDACs and/or user equipment devices are only able to reach some but not all of the other communication partners. The control information may comprise an information indicating that the base station is requested to organize a configuration of a network formed by the communication partners such that the controller 46 modifies resources like transmission frequencies, transmission times, codes or transmission spaces of the base station, the user equipment or of the SUDAC, i.e., the user equipment 30 and/or the SUDAC 10 may be configured for transmitting the control information indicating that the base station is requested to organize the network.

The base station 40 may be configured for transmitting a response information to the SUDAC 10 and/or to the user equipment 30 based on the control information indicating that the SUDAC 10 and/or the user equipment 30 are requested to utilize parts of the frequency domain, the time domain, the code domain or the space domain. I.e., the response information and/or the allocation information may related to the SUDAC 10 and/or to the user equipment 30 and to transmission domains of transmission or reception signals of the SUDAC 10 and/or of the user equipment 30.

Claims

SUDAC (10; 10') comprising:

a first wireless communication interface (12), configured for using ultra-high frequency in order to establish at least one backend communication link (14; 14a-c) with a base station (40); and

a second wireless communication interface (16), configured for using extremely-high frequency in order to establish at least one frontend communication link (18) with a user equipment (30); and

a processor (22),

wherein the processor is configured for at least partially forwarding a user information signal (32b) received via the frontend communication link (18) as a communication signal (42a) to be transmitted via the backend communication link (14; 14a-c) while frequency converting the extremely- high frequency to the ultra-high frequency; or

wherein the processor (22) is configured for at least partially forwarding the communication signal (42b) received via the backend communication link (14; 14a-c) as the user information signal (32a) to be transmitted via the frontend communication link (18) while frequency converting the ultra-high frequency to the extremely-high frequency;

wherein the processor (22) is configured for extracting control information (24) from the user information signal (32b) and for controlling forward parameters of the first or the second wireless communication interface based on the control information (24);

wherein the forward parameters relates at least to one of a time, a frequency, a space or a code resource of the backend communication link (14; 14a-c) or the frontend communication link (18); and

wherein the processor (22) is configured for frequency converting the user information signal (32b) received at extremely-high frequency to the communication signal (42a) at the ultra-high frequency and for frequency converting the

communication signal (42b) at the extremely-high frequency to the communication signal (32a) at the ultra-high frequency; or

wherein the SUDAC ( 10; 10') comprises an analog to digital converter (26a) configured for digitizing the user information signal received at extremely-high frequency, and a digital to analog converter (28b) configured for analogizing a digitalized communication signal to obtain the communication signal at the ultra-high frequency wherein the processor (22) is configured for generating the digitalized communication signal (42a) based on the digitalized user information signal.

SUDAC according to claim 1 , wherein the frontend communication link (18) comprises a plurality of signaling channels (54a-c) and at least one payload channel (56a-c), wherein the payload channel (56a-c) is associated to a signaling channel (54a-c) and wherein the processor (22) is configured for adapting parameters of the signaling channel (54a-c) associated to the payload channel based on the control information (24) and wherein the processor is configured to forward information of the payload channel.

SUDAC according to claim 1 or 2, wherein the frontend communication link (18) comprises a plurality of signaling channels (54a-c) and at least one payload channel (56a-c), wherein the processor (22) is configured for reducing a bandwidth of the payload channel (56a-c) such that during a second time duration, during which the bandwidth of the payload channel is reduced, a number of signaling channels is increased when compared to a first time duration having a same length as the second time duration during which the bandwidth of the payload channel is not reduced and wherein the processor is configured to forward the payload channel.

SUDAC according to one of previous claims, wherein the backend communication link (14; 14a-c) comprises a plurality of backend control channels (54a-c) and at least one backend payload channel (56a-c) and wherein the SUDAC (10; 10') is configured for transmitting or receiving control data (67) to or from the base station (40), wherein the processor (22) is configured for adapting the signaling channels (54a-c) to adapt a function of the base station (40) based on the control data (67) of a transmitted backend control channel (54a-c) or to adapt a function of the SUDAC (10; 10') based on the control data (67) of a received backend control channel (54a-c).

5. SUDAC according to one of previous claims, wherein the SUDAC (10; 10') is configured for utilizing the frontend communication link (18) to transmit or receive data to or from a second user equipment (39) or a second SUDAC.

SUDAC according to one of previous claims, wherein the frontend communication link (18) comprises a plurality of signaling channels (54a-c) and at least one payload channel (56a-c), wherein the SUDAC is configured for transmitting at least parts of the user information signal (32b) received via the frontend communication link (18) in a decoded version of the parts of the user information signal (32b) via the backend communication link (14; 14a-c) and to transmit at least parts of the communication signal (42b) received via the backend communication link (18) in a compressed version of the parts of the communication signal (42b) via the frontend communication link (14; 14a-c), wherein the processor (22) is further configured for adapting a rate of compression or encoding/decoding based on the control information (24) or based on a control signal received via the backend communication link (14; 14a-c).

SUDAC according to claim 6, wherein the processor (22) is configured for adapting the rate of compression and encoding/decoding based on a ratio of a bandwidth of the plurality of signaling channels (54a-c) and of the bandwidth of the at least one payload channel (56a-c).

SUDAC according to one of previous claims, wherein the frontend communication link comprises a first plurality of rendezvous channels (58; 58a-c), each rendezvous channel comprising a plurality of control channels (54a-c), wherein the processor (22) is configured for adapting an operation mode of the SUDAC based on the control information (24) contained in the plurality of control channels (54a-c); or

wherein the backend communication link (14; 14a-c) comprises second plurality of rendezvous channels (58; 58a-c) and wherein the SUDAC is configured for receiving information configured for adapting an operation mode of the SUDAC via a control channel (54a-c) of the backend communication link (14; 14a-c) or to transmit information configured for adapting an operation mode of the user equipment (30; 30a, 30b) or the base station (40) based on a control channel (54a-c) of the backend communication link (14; 14a-c).

SUDAC according to one of previous claims, wherein the first wireless communication interface (12) is configured for establishing a further backend

communication link (14b) to a further base station (41 ), using the ultra-high frequency, wherein the SUDAC is configured for receiving the user information signal (32b) from the user equipment (30) via the frontend communication link (18), wherein the user information signal (32b) comprises a first information related to the user equipment (30) and to the base station (40) and a second information related to a further user equipment (39) and to the further base station (41 ), wherein the SUDAC is configured for converting the extremely-high frequency and the first information to the ultra-high frequency and for converting the extremely-high frequency and the second information to the further ultra-high frequency.

10. SUDAC according to one of previous claims, wherein

the backend communication link (14; 14a-c) comprises a backend payload channel (56a-c) and wherein the frontend communication link (18) comprises a frontend payload channel (56a-c);

wherein the backend communication link (14; 14a-c) comprises a backend random access channel or wherein the frontend communication link (18) comprises a frontend random access channel;

wherein the SUDAC is configured for receiving a random frontend information (62) from a further user equipment using the frontend random access channel or to receive a random backend information (64) from a further base station (40b) using the backend random access channel; and

wherein the SUDAC is configured for transmitting the random frontend information (62) using the frontend communication link (18) or the backend communication link (14; 14a-c) or for sending the random backend information (64) using the frontend communication link (18) or the backend communication link (14; 14a-c).

1 1. SUDAC according to one of previous claims, wherein the SUDAC comprises a first operation mode (active) in which the SUDAC transmits or receives information via the backend communication link (14; 14a-c), wherein the processor (22) is configured to extract control information (24) from the communication signal (42b) received from the base station, the control information (24) indicating a sleep-mode request and wherein the processor (22) is configured for changing the first operation mode to a second operation mode (sleep) in which the SUDAC is configured for not transmitting information via the backend communication link (14; 14a-c) or the frontend communication link (18).

12. SUDAC according to one of previous claims, wherein the SUDAC is configured for establishing a first and a second backend communication link ( 4; 14a-c), to receive a first and a second payload information (56a-c) using resources (time, frequency, space, code) separated from each other and to transmit the frontend communication signal (18) comprising the first and the second payload information (54a-c) to perform backend carrier aggregation; and/or

wherein the SUDAC is configured for establishing a first and a second frontend communication link (18), to receive a first and a second payload information (56a-c) using resources (time, frequency, space, code) separated from each other and to transmit the backend communication signal (14; 14a-c) comprising the first and the second payload information (54a-c) to perform frontend carrier aggregation.

13. User equipment (30; 30a, 30b) comprising:

a first wireless communication interface (36) configured for using ultra-high frequency in order to establish at least one direct communication link (34). with a base station (40); and

a second wireless communication interface (37) configured for using extremely-high frequency in order to establish at least one frontend communication link (18) with a SUDAC (10; 10');

wherein the user equipment (30; 30a, 30b) is configured for receiving a user signal partially (42) via the direct communication link (34). and at least partially (32a) via the frontend communication link (18);

wherein the user equipment (30; 30a, 30b) is associated to the base station (40);

wherein the user equipment (30; 30a, 30b) is configured for generating the user information signal (32b) based on an information (38, 38') received from a further user equipment (39) associated to a further base station (41 ) such that the user information signal (32b) comprises information related to the user equipment (30; 30a, 30b) and information related to the further user equipment (39).

14. User equipment according to claim 13, wherein the user equipment is configured for receiving the information (38) from the further user equipment via a direct connection to the user equipment or via an indirect connection utilizing the SUDAC (10) forwarding the information (38) from the further user equipment (39).

15. User equipment according to claim 13 or 14, wherein the frontend communication link (18) comprises a plurality of control channels (54a-c) and at least one payload channel (56a-c), wherein the user equipment is configured for adapting a bandwidth of the payload channel (56a-c) in the frontend communication link (18).

16. User equipment according to one of claims 13-15, comprising a regular mode and a piggyback mode and wherein the frontend communication link (18) comprises at least one payload channel (56a-c) and a plurality of control channels (54a-c), wherein the user equipment (39) is configured for transmitting the user information signal using (32b) at least one control channel (54a-c) and the payload channel

(56a-c) when operating in the regular mode and for transmitting the user information signal (32b) using the payload channel (56b) and not the control channel when operating in the piggyback mode.

17. User equipment according to one of claims 13-16, wherein the frontend communication link (18) or the direct link (34) comprises a plurality of control channels (54a-c) and wherein the user equipment is configured for transmitting a control information (24) via the control channels (54a-c) comprising an information related to a control of the SUDAC (10) via the base station (40), and comprising information related to the SUDAC.

User equipment according to one of claims 13-17, wherein the user equipment is configured for transmitting a payload information in a payload channel (56a-c) of the frontend communication link (18) and a random frontend information (62) in the payload channel (56a-c) or a frontend random access channel (62') of the frontend communication link (18) and to receive a random information (62') from the SUDAC (10), wherein the user equipment (30; 30a, 30b) comprises a processor (31 ) configured for processing the random information (62).

User equipment according to claim 18, wherein the processor (31 ) is configured for comparing the random frontend information (62) and the received random information (62) and to obtain an information (62) related to the frontend communication link (18) based on the comparison when the random frontend

information (62) was sent, or to evaluate the random information (62) to obtain information from a further user equipment (39) or a further base station (40b; 41 ) when the random frontend information (62) was not sent.

20. Base station (40; 40a, 40b) comprising:

a plurality of wireless communication interfaces (44a-c);

a controller (46) configured for controlling the plurality of wireless communication interfaces (44a-c) such that a multiple antenna function of the plurality of wireless communication interfaces is obtained;

wherein the base station (40; 40a, 40b) is configured for receiving control information via at least one of the plurality of wireless communication interfaces (44a-c), related to a SUDAC (10; 10a-c) communicating with the base station (40; 40a, 40b) directly or via a user equipment (30; 30a, 30b);

wherein the controller (46) is configured for adapting transmission characteristics of the multiple antenna function based on the control information.

21. Base station according to claim 20, wherein the controller (46) is configured for time variant adapting the transmission characteristics of the multiple antenna function based on a received information such that the multiple antenna function is based on a spatial multiplexing when the base station transmits a payload information (56) to the user equipment (30; 30a, 30b) or such that the multiple antenna function is based on a beamforming when the base station transmits a status/control information (54a-c) to the SUDAC (10; 10a-c).

22. Base station according to claim 20, wherein the controller (46) selects the transmission characteristics of the multiple antenna function such that the multiple antenna function is based on a spatial multiplexing when the base station transmits a payload information (56) to a system, comprising at least two SUDACs (10; 10a-c) coupled to each other, and/or when the base station transmits a status/control information (54a-c) to the system.

23. Base station according to one of claims 20-22, wherein the control information comprises geographic information and wherein the transmission characteristics relates at least to a directional radio pattern of a signal transmitted by the base station (40; 40a, 40b), such that the controller (46) is configured for adapting a preferred direction of a backend communication link (14; 14a-c) established between the base station (40; 40a-c) and the SUDAC (10; 10a-c) or wherein the control information relates to a preferred direction of a direct link (34) established between the base station (40; 40a-c) and the user equipment (30; 30a, 30b) such that the controller (46) is configured for adapting a preferred direction of the direct link (34) or wherein the control information relates to a bandwidth information and wherein the controller (46) is configured to adapt a bandwidth of the backend communication link (14; 14a-c).

24. Base station according to one of claims 20-23, wherein the control information comprises an information indicating that the base station (40; 40a, 40b) is requested to organize a configuration of a network comprising the user equipment (30; 30a, 30b), the SUDAC (10; 10a-c) and the base station (40; 40a-b), wherein the configuration comprises at least a control of transmission frequencies or transmission times of the base station (40; 40a-b), the user equipment (30; 30a-b) or the SUDAC (10; 10a-c).

25. Base station according to one of claims 20-24, wherein the base station(40; 40a-b) is configured for transmitting a response information based on the control information and related to the user equipment (30; 30a-b), the response information comprising an information related to a frequency or a time slot of a transmission or reception signal of the user equipment (30; 30a-b) or of the SUDAC (10; 10a-c).

26. Base station according to claim 25, wherein the response information is related to an information indicating that the user equipment (30; 30a, 30b) is requested to change a currently used SUDAC (10; 10a-c).

27. Base station according to one of claims 20-26, wherein the base station (40; 40a, 40b) is configured for transmitting a control information via a backend communication link (14; 14a-c) associated to a SUDAC (10; 10a-c), the control information indicating that the SUDAC (10; 10a-c) is requested to stop transmitting a payload data using the backend communication link (14; 14a-c).

28. Base station according to one of claims 20-27, wherein the base station is configured for receiving an equipment allocation information related to the user equipment (30; 30a, 30b) and to send a base station (40; 40a, 40b) allocation information based on the reception or wherein the base station is configured for

transmitting the base station allocation information and for receiving the equipment allocation information related to the user equipment (30; 30a, 30b) based on the transmission;

wherein the equipment allocation information and the base station allocation information relate to an allocation of time, frequency, space or code resource of a transmission media by which information is transmitted between the base station, the SUDAC and/or the user equipment (30; 30a, 30b);

wherein the controller (46) is configured to determine a resource allocation such that a rate of a resource utilization of the base station, of the user equipment or of the SUDAC is above a predefined threshold.

Base station according to one of claims 20-28, wherein the base station (40; 40a, 40b) is configured for receiving payload information related to the user equipment (30; 30a, 30b) via the backend communication link (14; 14a-c), the user equipment (30; 30a, 30b) being related to the base station (40; 40a, 40b), wherein the payload information is received from a SUDAC (10; 10a-c), the SUDAC transmitting the payload information as a piggyback information piggybacked to a payload information of a further user equipment (39), wherein the controller (46) is configured to extract the information related to the user equipment (30; 30a, 30b).

Base station according to claim 29, wherein the further (39) user equipment is associated to a further base station (41 ) and not to the base station (40; 40a, 40b).

SUDAC System (50; 60; 70; 70'; 80; 90) comprising:

a SUDAC (10; 10'; 10a-b) according to one of claims 1-12;

a user equipment (30; 30a, 30b) according to one of claims 13-19; and

a base station (40; 40a, 40b; 40'). according to one of claims 20-29.

SUDAC System (90) according to claim 31 , further comprising a BS-side-SUDAC (92a, 92b) configured to establish an inter-backend link (94a, 94b) to the base station (40') using extremely-high frequency and for establishing intra-network links (96a-i) to the SUDAC (10; 10'; 10a-b) and to the user equipment (30; 30a, 30b).

33. SUDAC System according to claim 31 or 32, wherein the SUDAC (10; 10'; 10a-b), the user equipment (30; 30a-b) or the base station (40; 40a; 40b; 40') is configured to determine an allocation of a utilized transmission resource (time, frequency, space, code) for the SUDAC System.

34. Method (2000) for signal forwarding

using (2010) ultra-high frequency in order to establish at least one backend communication link with a base station; and

using (2020) extremely-high frequency in order to establish at least one frontend communication link with a user equipment;

frequency converting (2030) the extremely-high frequency to the ultra-high frequency and at least partially forwarding a user information signal received via the frontend communication link as a communication signal to be transmitted via the backend communication link; or

frequency converting (2040) the ultra-high frequency to the extremely-high frequency and at least partially forwarding the communication signal received via the backend communication link as the user information signal to be transmitted via the frontend communication link;

extracting (2050) control information from the user signal and controlling forward parameters of a first or a second wireless communication interface based on the control information; and

frequency converting (2060) the user information signal received at extremely-high frequency to the communication signal at the ultra-high frequency and frequency converting the communication signal at the extremely-high frequency to the communication signal at the ultra-high frequency; or

digitizing (2070) the user information signal received at extremely-high frequency, and analogizing a digitalized communication signal to obtain the communication signal at the ultra-high frequency and generating the digitalized communication signal based on the digitized user information signal.
35. Method (2100) for transmitting or receiving a signal with a user equipment
using (21 10) ultra-high frequency in order to establish at least one direct communication link with a base station;
using (2120) extremely-high frequency in order to establish at least one frontend communication link with a SUDAC;
receiving (2130) a user signal at least partially via the frontend communication link with a user equipment associated to the base station; and
generating (2140) the user information signal based on an information received from a further user equipment associated to a further base station such that the user information signal comprises information related to the user equipment and information related to the further user equipment.
36. Method (2200) for transmitting or receiving a signal with a base station
controlling (2210) a plurality of wireless communication interfaces of the base station such that a multiple antenna function of the plurality of wireless communication interfaces is obtained;
receiving (2220) control information via at least one of the plurality of wireless communication interfaces, related to a SUDAC or a user equipment communicating with the base station; and
adapting (2230) transmission characteristics of the multiple antenna function based on the control information.
37. Non transitory storage medium having stored thereon a computer program having a program code for performing, when running on a computer, a method according to one of claims 34-36.