Wireless relay device using link frequency and operation method thereof

Abstract

An operation method of a wireless relay device provided by an embodiment of the present invention comprises: (a) a step for receiving a downlink signal; (b) a step for determining the frequency of an output first signal as one link frequency, among a plurality of preset link frequencies, which is different from the frequency of the downlink signal; and (c) a step for using the input downlink signal to output the first signal having the determined link frequency and a second signal having a service frequency of a base station.

Description

Wireless relay device using link frequency and its operating method

[0001] The present invention relates to a wireless relay device using a link frequency and an operating method thereof.

[0002] A wireless signal relay device (hereinafter abbreviated as a “wireless relay device,” “relay device,” or “relay”) performs the function of receiving a wireless signal in a wireless communication system, amplifying it, and retransmitting it.

[0003] Wireless repeaters can be used in a variety of wireless communication technologies. For example, in mobile communication networks such as LTE (long term evolution), 5G (Generation 5), and NR (New Radio), wireless signal repeaters are used to extend communication range and improve signal quality. Furthermore, in satellite communication systems, repeaters enable wireless communication between Earth and satellites. Furthermore, repeaters play a crucial role in various fields, including wireless networks, wireless communication systems, and wireless power transmission.

[0004] The frequencies of the signal input to the input antenna of a repeater and the signal output from the output antenna are usually the same. Meanwhile, the signal output from the output antenna may be fed back to the input antenna. Due to this feedback signal, if the degree of isolation between the output antenna and the input antenna of the repeater is not very large compared to the overall gain of the repeater, the feedback signal may cause oscillation in the repeater, and the repeater may not be able to transmit the intended signal.

[0005] One embodiment of the present invention proposes a method for preventing oscillation from occurring in a wireless relay device.

[0006] One embodiment of the present invention proposes a method for setting the frequency of an input signal and the frequency of an output signal differently in a wireless relay device.

[0007] One embodiment of the present invention proposes a method for determining the frequency of an output signal for a downlink signal in a wireless relay device.

[0008] One embodiment of the present invention proposes a method for determining the frequency of an output signal when an uplink signal is input to a radio relay device.

[0009] An operating method of a wireless relay device provided by one embodiment of the present invention comprises: (a) receiving a downlink signal; (b) determining a frequency of an outputted first signal as one link frequency different from the frequency of the downlink signal among a plurality of preset link frequencies; and (c) using the inputted downlink signal, outputting a first signal having the determined link frequency and a second signal having a service frequency of a base station.

[0010] Here, the step (b) is characterized in that, if the frequency of the input downlink signal is the service frequency, the frequency of the first signal is determined as one of the plurality of preset link frequencies.

[0011] Here, the step (c) includes: a step of converting a downlink signal of the service frequency into a signal of an intermediate frequency; a step of frequency up-converting the converted intermediate frequency signal into a second signal of the service frequency; and a step of frequency up-converting the converted intermediate frequency signal into a first signal of the determined link frequency.

[0012] Here, the step (b) is characterized in that, if the frequency of the input downlink signal is one of the plurality of preset link frequencies, the frequency of the first signal is determined as one of the link frequencies other than the frequency of the input downlink signal among the plurality of preset link frequencies.

[0013] Here, the step (c) includes: a step of converting the input downlink signal into a signal of an intermediate frequency; a step of frequency up-converting the converted intermediate frequency signal into a second signal of the service frequency; and a step of frequency up-converting the converted intermediate frequency signal into a first signal of the determined link frequency.

[0014] A wireless relay device provided by one embodiment of the present invention includes a communication unit that receives a downlink signal; and a processor that determines a frequency of a first signal to be output as one link frequency different from the frequency of the downlink signal among a plurality of preset link frequencies, generates a first signal having the determined link frequency and a second signal having a service frequency of a base station using the input downlink signal, and outputs the first signal and the second signal through the communication unit.

[0015] Here, the processor determines the frequency of the first signal as one of the plurality of preset link frequencies if the frequency of the input downlink signal is the service frequency.

[0016] Here, the communication unit includes a down converter that converts a downlink signal of the service frequency into a signal of an intermediate frequency; a first up converter that frequency-upconverts the converted intermediate frequency signal into a second signal of the service frequency; and a second up converter that frequency-upconverts the converted intermediate frequency signal into a first signal of the determined link frequency.

[0017] Here, if the frequency of the input downlink signal is one of the plurality of preset link frequencies, the processor determines the frequency of the first signal as one of the plurality of preset link frequencies other than the frequency of the input downlink signal.

[0018] Here, the communication unit includes a down converter that converts the input downlink signal into a signal of an intermediate frequency; a first up converter that frequency-upconverts the converted intermediate frequency signal into a second signal of the service frequency; and a second up converter that frequency-upconverts the converted intermediate frequency signal into a first signal of the determined link frequency.

[0019] An operating method of a wireless relay device provided by one embodiment of the present invention comprises the steps of: (a) receiving a first uplink signal of a service frequency of a base station and a second uplink signal of the first link frequency, which is one of a plurality of preset link frequencies relayed from another relay device; (b) determining a frequency of an output signal based on whether the wireless relay device is the last wireless relay device; and (c) generating an output signal of the determined frequency using the first uplink signal and the second uplink signal, wherein the last wireless relay device directly transmits the output signal of the wireless relay device to the base station without relaying it with another wireless relay device.

[0020] Here, the step (b) includes a step of determining the frequency of the output signal as the service frequency if the wireless relay device is the last wireless relay device.

[0021] Here, the step (c) includes: a step of converting the first uplink signal into a first intermediate signal of an intermediate frequency; a step of frequency up-converting the first intermediate signal into a signal of the service frequency; a step of converting the second uplink signal into a second intermediate signal of an intermediate frequency; and a step of frequency up-converting the second intermediate signal into a signal of the service frequency.

[0022] Here, the step (b) includes a step of determining the frequency of the output signal as a second link frequency other than the first link frequency among the plurality of preset link frequencies, if the wireless relay device is not the last wireless relay device.

[0023] Here, the step (c) includes: a step of converting the first uplink signal into a first intermediate signal of an intermediate frequency; a step of frequency up-converting the first intermediate signal into a signal of the determined second link frequency; a step of converting the second uplink signal into a second intermediate signal of an intermediate frequency; and a step of frequency up-converting the second intermediate signal into a signal of the determined second link frequency.

[0024] A wireless relay device provided by one embodiment of the present invention includes a communication unit that receives a first uplink signal of a service frequency of a base station and a second uplink signal of a first link frequency, which is one of preset link frequencies relayed from another relay device; and a processor that determines a frequency of an output signal based on whether the wireless relay device is the last wireless relay device, generates an output signal of the determined frequency using the first uplink signal and the second uplink signal, and outputs the output signal through the communication unit, wherein the last wireless relay device directly transmits the output signal of the wireless relay device to the base station without relaying it with another wireless relay device.

[0025] Here, the processor determines the frequency of the output signal as the service frequency if the wireless relay device is the last wireless relay device.

[0026] Here, the communication unit includes a first down converter that converts the first uplink signal into a first intermediate signal of an intermediate frequency; an up converter that frequency up-converts the first intermediate signal into a signal of the service frequency; a second down converter that converts the second uplink signal into a second intermediate signal of an intermediate frequency; and an up converter that frequency up-converts the second intermediate signal into a signal of the service frequency.

[0027] Here, if the wireless relay device is not the last wireless relay device, the processor determines the frequency of the output signal as a second link frequency other than the first link frequency among the plurality of preset link frequencies.

[0028] Here, the communication unit includes a first down converter that converts the first uplink signal into a first intermediate signal of an intermediate frequency; an up converter that frequency-upconverts the first intermediate signal into a signal of the determined second link frequency; a second down converter that converts the second uplink signal into a second intermediate signal of an intermediate frequency; and an up converter that frequency-upconverts the second intermediate signal into a signal of the determined second link frequency.

[0029] According to an embodiment of the present invention, by using a link frequency in a wireless relay device to make the frequency of an input signal different from the frequency of an output signal, oscillation is prevented in the wireless relay device by an infinite loop due to feedback of the output signal, so that the wireless relay device can stably relay a wireless signal.

[0030] The effects that can be achieved through specific examples of this specification are not limited to the effects listed above. For example, a person with ordinary skill in the relevant technical field may understand or derive various technical effects from this specification. Accordingly, the specific effects of this specification are not limited to those explicitly described herein, but may include various effects that can be understood or derived from the technical features of this specification.

[0031] The following drawings are intended to illustrate specific examples of the present specification. The names of specific devices and the names of specific signals / messages / fields depicted in the drawings are provided for illustrative purposes only, and the technical features of this specification are not limited to the specific names used in the drawings.

[0032] Figure 1 is a diagram explaining oscillation that may occur in a wireless repeater device depending on the relationship between feedback isolation and gain.

[0033] Figure 2 is a diagram explaining a feedback signal and oscillation when the frequencies of the input signal and output signal of a wireless relay device are different.

[0034] FIG. 3 is a diagram illustrating the configuration of a wireless relay device that restores the frequency of an output signal when the frequencies of an input signal and an output signal are different.

[0035] FIG. 4a and FIG. 4b are drawings explaining the concept of wireless relay according to an embodiment of the present invention.

[0036] FIG. 5a is a diagram explaining the configuration of a wireless relay device according to an embodiment of the present invention and its operation when the forward input frequency is a service frequency.

[0037] FIG. 5b is a diagram explaining the operation of a wireless relay device according to an embodiment of the present invention when the forward input frequency is the first frequency.

[0038] FIG. 5c is a diagram explaining the operation of a wireless relay device according to an embodiment of the present invention when the forward input frequency is a second frequency.

[0039] FIG. 6A is a diagram explaining the operation of a wireless relay device according to an embodiment of the present invention when the reverse input frequency is the service frequency and the first frequency.

[0040] FIG. 6b is a diagram explaining the operation of a wireless relay device according to an embodiment of the present invention when the reverse input frequency is a service frequency and a second frequency.

[0041] FIG. 7 is a drawing illustrating the operation of a wireless relay device that receives a forward signal according to an embodiment of the present invention.

[0042] FIG. 8 is a drawing illustrating the operation of a wireless relay device that receives a reverse signal according to an embodiment of the present invention.

[0043] FIG. 9 is a drawing explaining the configuration of a wireless relay device according to an embodiment of the present invention.

[0044] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. Throughout the description of each drawing, similar reference numerals have been used to designate similar components.

[0045] Although the terms "first," "second," "A," "B," etc. may be used herein to describe various components, the components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, the first component could be referred to as the second component, and similarly, the second component could also be referred to as the first component. Furthermore, the term "and / or" includes any combination of multiple related listed items or any one of multiple related listed items.

[0046] When a component is referred to as being "connected" or "connected" to another component, it should be understood that it may be directly connected or connected to that other component, but that there may be other components intervening. Conversely, when a component is referred to as being "directly connected" or "connected" to another component, it should be understood that there are no other components intervening.

[0047] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0048] Unless otherwise defined, the terms used herein, including technical or scientific terms, have the same meanings commonly understood by those of ordinary skill in the art to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having meanings consistent with their meanings within the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0049] Before proceeding with a detailed description of the drawings, it should be clarified that the division of components in this specification is merely based on the primary function each component is responsible for. In other words, two or more components described below may be combined into a single component, or a single component may be further subdivided into two or more components with more specific functions.

[0050] Furthermore, each component described below may, in addition to its primary function, perform some or all of the functions assigned to other components. Furthermore, some of the primary functions assigned to each component may be dedicated to other components. Therefore, the existence of each component described herein should be interpreted functionally.

[0051] As used herein, "A or B" can mean "only A," "only B," or "both A and B." In other words, as used herein, "A or B" can be interpreted as "A and / or B." For example, as used herein, "A, B or C" can mean "only A," "only B," "only C," or "any combination of A, B and C."

[0052] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0053] As used herein, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, as used herein, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted as equivalent to “at least one of A and B.”

[0054] Additionally, in the present specification, “at least one of A, B and C” may mean “only A”, “only B”, “only C”, or “any combination of A, B and C”. Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” may mean “at least one of A, B and C”. Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0055] Before describing an embodiment of the present invention, oscillation that may occur in a wireless relay device will be described.

[0056] Figure 1 is a diagram explaining oscillation that may occur in a wireless repeater device depending on the relationship between feedback isolation and gain.

[0057] Referring to Fig. 1, G represents the overall system gain of the wireless repeater (100). The wireless repeater (100) receives a signal at a frequency of f1 through an input antenna (not shown), amplifies the input signal according to the gain G, and outputs a signal at a frequency of f1 through an output antenna (not shown). Typically, the frequencies of the input signal and the output signal are the same. In Fig. 1, the frequencies of the input signal and the output signal are assumed to be f1.

[0058] In a typical wireless repeater, if the isolation of the path that feeds back from the output side to the input side is not sufficiently greater than the overall system gain (G), the output signal may flow into the input side of the wireless repeater (100). This is called a feedback signal. Since the feedback signal is a part of the output signal, the frequency of the feedback signal becomes f1. This feedback signal is amplified and output by the wireless repeater (100), and a part of it is fed back, which may cause an infinite loop. If an infinite loop due to this feedback signal occurs, the signal quality may deteriorate or oscillation may occur, and the wireless repeater (100) may not be able to relay signals normally. Here, 'oscillation' refers to a phenomenon in which an unwanted signal is generated in an electronic device. However, whether oscillation occurs or not can be determined based on the system gain (G) and feedback isolation of the wireless repeater. Here, the feedback isolation may be determined based on the physical distance between the input and output ends and the environment of the wireless channel, etc., in order to minimize signal interference.

[0059] When the feedback isolation is sufficiently greater than the system gain, the wireless repeater (100) can operate normally and relay signals. Here, the degree of sufficiently greater can vary depending on the type of wireless signal and the required performance. When the feedback isolation is not sufficiently greater than the system gain, signal quality deteriorates or micro-oscillations occur, preventing the wireless repeater (100) from relaying signals normally. When the feedback isolation is equal to or less than the system gain, oscillations occur, preventing the wireless repeater (100) from relaying signals normally.

[0060] Typically, a wireless repeater (100) is designed to have sufficient feedback isolation to prevent internal oscillation, so oscillation rarely occurs due to hardware problems within the wireless repeater (100). In most cases, the feedback isolation is lowered by the feedback path through which the output signal is input to the input antenna due to the external environment, which causes oscillation. Therefore, in order to prevent oscillation in the wireless repeater (100), the external environment must be controlled to prevent the feedback isolation from being lowered. However, control of the external environment is not often possible. For example, it is impossible to control large trucks, birds, buildings, etc. In particular, in cases where there are many external factors that can lower the feedback isolation, such as narrow indoor spaces or urban environments, normal operation of the wireless repeater may be more difficult. To solve this problem, the frequency of the input signal and the frequency of the output signal in the wireless repeater (100) can be set to be different.

[0061] Figure 2 is a diagram explaining a feedback signal and oscillation when the frequencies of the input signal and output signal of a wireless relay device are different.

[0062] Referring to FIG. 2, the frequency of the input signal of the wireless repeater (100) is set to f1, and the frequency of the output signal is set to f2. Since the feedback signal is a part of the output signal, the frequency of the feedback signal is f2. At this time, a filter is applied to the feedback signal fed back to the input terminal from the wireless repeater (100) so that the feedback signal can be removed. As the feedback signal is removed, an infinite loop does not occur, and therefore, oscillation does not occur.

[0063] However, when the frequencies of the input signal and the output signal are different, as in Fig. 2, it is necessary to restore the frequency f2 of the output signal to the frequency f1 of the input signal. Referring to Fig. 3, an example of a wireless relay device that restores the frequency when the frequencies of the input and output signals are different is described.

[0064] FIG. 3 is a diagram illustrating the configuration of a wireless relay device that restores the frequency of an output signal when the frequencies of an input signal and an output signal are different.

[0065] Referring to FIG. 3, the wireless relay system (300) includes a master relay device (310) and a slave relay device (320). When the frequency of a signal input to the wireless relay system (300) is f1, the master relay device (310) outputs a signal of a frequency f2 that is different from the frequency f1 of the input signal. The slave relay device (320) receives the signal f2 output from the master relay device (310), restores it to f1, and outputs it. The frequencies of the input signal and the output signal of the entire wireless relay system (300) are the same as f1, and a portion of the output signal of the slave relay device (320) can be input to the master relay device (310) as a feedback signal. However, since the wireless relay system (300) of FIG. 3 is composed of a master relay device (310) and a slave relay device (320), and a considerable distance is provided between the output terminal of the slave relay device (320) and the input terminal of the master relay device (310), the feedback isolation between the output terminal of the slave relay device (320) and the input terminal of the master relay device (310) becomes significantly increased. In this way, since the wireless relay system (300) can greatly increase the feedback isolation, the feedback isolation can be maintained high even when affected by the external environment. Therefore, the feedback isolation can become much larger than the gain (G') of the wireless relay system, and therefore, the frequencies of the input and output signals of the wireless relay system (300) are the same, but oscillation does not occur. However, this wireless relay system (300) requires additional hardware by a pair of master relay devices (310) and slave relay devices (322), and there is a problem that communication is not performed in the section between the master relay device (310) and slave relay devices (322).

[0066] Below, a wireless relay device according to an embodiment of the present invention is described.

[0067] FIG. 4a and FIG. 4b are drawings explaining the concept of wireless relay according to an embodiment of the present invention.

[0068] Figure 4a illustrates an example in which a signal transmitted from a base station is transmitted in the forward direction (=downlink) through multiple relay devices.

[0069] Referring to FIG. 4A, it is assumed that the base station (400) transmits a signal of a service frequency (fs), which is a frequency served by the corresponding communication system. The signal transmitted by the base station (400) can be transmitted to terminals (not shown) through relay devices, and in FIG. 4A, four relay devices (410, 420, 430, 440) are exemplified.

[0070] The first relay device (410) can receive a signal of a service frequency (fs) and output a signal of the service frequency (fs). In addition, the first relay device (410) can frequency-convert the signal of the service frequency (fs) and output a signal of a first frequency (f1) different from the service frequency (fs). The signal of the service frequency (fs) output by the first relay device (410) can be transmitted to terminals (not shown) located around the first relay device (410). Meanwhile, the signal of the first frequency (f1) output by the first relay device (410) becomes an input signal of the second relay device (420), which is a relay device of the next order.

[0071] The second relay device (420) can receive a signal of the first frequency (f1), perform frequency conversion on it, and output a signal of the service frequency (fs). In addition, the second relay device (420) can convert the signal of the first frequency (f1) to output a signal of the second frequency (f2) different from the first frequency (f1). The signal of the service frequency (fs) output by the second relay device (420) can be transmitted to terminals (not shown) located around the second relay device (420). Meanwhile, the signal of the second frequency (f2) output by the second relay device (420) becomes an input signal of the third relay device (430), which is the relay device of the next order.

[0072] The third relay device (430) can receive a signal of the second frequency (f2), perform frequency conversion on it, and output a signal of the service frequency (fs). In addition, the third relay device (430) can convert the signal of the second frequency (f2) to output a signal of the first frequency (f1). The signal of the service frequency (fs) output by the third relay device (430) can be transmitted to terminals (not shown) located around the third relay device (430). Meanwhile, the signal of the first frequency (f1) output by the third relay device (430) becomes an input signal of the fourth relay device (440), which is the relay device of the next order.

[0073] The operation of the fourth relay device (440) is the same as that of the second relay device (420). That is, the fourth relay device (440) can receive a signal of the first frequency (f1), perform frequency conversion, and output a signal of the service frequency (fs). In addition, the fourth relay device (440) can frequency convert the signal of the first frequency (f1) and output a signal of the second frequency (f2). The signal of the service frequency (fs) output by the fourth relay device (440) can be transmitted to terminals (not shown) located around the fourth relay device (440). Meanwhile, the signal of the second frequency (f2) output by the fourth relay device (440) can become an input signal of the next relay device (not shown).

[0074] In this way, in the embodiment of the present invention, each relay device can frequency-convert a signal input to the relay device and output one of the service frequency (fs) used in the wireless communication system and other frequencies (f1, f2). The signals of the service frequency (fs) and other frequencies (f1, f2) become input signals of other relay devices. Since the other frequencies (f1, f2) serve as a link between the relay devices, they can be referred to as 'link frequencies'. Although FIG. 4A illustrates that there are two link frequencies, there may be two or more link frequencies. For example, when there are three link frequencies, the first relay device (410) can output f1, the second relay device (420) can output f2, the third relay device can output f3, and the fourth relay device can output f1.

[0075] Meanwhile, when selecting one of the link frequencies, the wireless relay device may select a link frequency suitable for its surrounding environment (e.g., tunnel, indoors, etc.) by considering its surrounding environment. Alternatively, candidate link frequencies suitable for each wireless relay device may be set in advance. For example, if there are four link frequencies in total (f1, f2, f3, f4), the first wireless relay device (410) may be set to select one of f1, f2, f3, and f4, the second wireless relay device (420) may be set to select one of f2, f3, and f4, and the third wireless relay device (430) and the fourth wireless relay device (440) may be set to select one of f3 and f4.

[0076] Figure 4b illustrates an example in which an uplink signal is transmitted in the reverse direction (=uplink) through multiple relay devices.

[0077] The fourth relay device (440) can receive a signal of a service frequency (fs) transmitted by a peripheral terminal (not shown) and a signal of a second frequency (f2) output from another relay device (not shown), perform frequency conversion on each of them, and output a signal of a first frequency (f1). The signal of the first frequency (f1) output by the fourth relay device (440) can become an input signal of the third relay device (430), which is the relay device of the next order.

[0078] The third relay device (430) can receive a signal of a service frequency (fs) transmitted by a surrounding terminal (not shown) and a signal of a first frequency (f1) output from the fourth relay device (440), perform frequency conversion on each of them, and output a signal of a second frequency (f2). The signal of the second frequency (f2) output by the third relay device (430) can become an input signal of the second relay device (420), which is the relay device of the next order.

[0079] The second relay device (420) can receive a signal of a service frequency (fs) transmitted by a surrounding terminal (not shown) and a signal of a second frequency (f2) output from a third relay device (430), convert the frequencies of each, and output a signal of a first frequency (f1). The signal of the first frequency (f1) output by the second relay device (420) can become an input signal of the first relay device (410), which is the relay device of the next order.

[0080] The first relay device (410) can receive a signal of a service frequency (fs) transmitted by a peripheral terminal (not shown) and a signal of a first frequency (f1) output from the second relay device (420), convert their frequencies, and output a signal of a service frequency (fs). Since the signal output from the first relay device (410) is directly transmitted to the base station (400), the first relay device (410) outputs a signal of a service frequency (fs) rather than a signal of a second frequency (f2), which is a link frequency. In other words, since the first relay device (410) is the last wireless relay device on the reverse signal path transmitted toward the base station, it outputs a signal of a service frequency (fs).

[0081] Hereinafter, the internal configuration and detailed operation of a wireless relay device according to an embodiment of the present invention will be described with reference to FIGS. 5a to 5d and FIGS. 6a and 6b.

[0082] FIG. 5a is a diagram explaining the configuration of a wireless relay device according to an embodiment of the present invention and its operation when the forward input frequency is a service frequency.

[0083] A wireless relay device (500) includes two multiplexers (510, 570), up-converters (521, 523, 561) that perform frequency up-conversion, down-converters (522, 524, 562) that perform frequency down-conversion, a distributor (530) that distributes signals, a combiner (540) that combines input signals and outputs them, and a reference clock generation unit (550) that generates a reference clock.

[0084] Below, the operation of the wireless relay device (500) when the frequency of the input signal in the forward direction is the service frequency (fs) is described. When the frequency of the input signal is the service frequency (fs), the operation may correspond to the operation of the first wireless relay device (410) in FIG. 4a.

[0085] The reference clock generation unit (550) supplies the same reference signal to the up converters (521, 523, 562) and the down converters (522, 524, 561). For reference, a local signal generator may be used for each converter among a pair of down converters and up converters (561 / 562, 521 / 522, and 523 / 524), or one local signal generator may be shared. This may be determined according to the frequency of the intermediate frequency (IF) channel filter used. In Fig. 5a, it is assumed that the down converters and up converters are equipped with local signal generators inside.

[0086] When the signal input through the multiplexer (MUX) (570) is a signal of the service frequency (fs), the down converter (561) down-converts the signal of the service frequency (fs) to an intermediate frequency (IF) and then outputs a signal of the intermediate frequency signal (fs_IF) containing only the signal component of the service frequency (fs) using a channel filter. The intermediate frequency signal (fs_IF) of the service frequency output from the down converter (561) is input to the distributor (530). The distributor (530) transmits the signal to two up converters (521, 523).

[0087] The up converter (521) up-converts the intermediate frequency signal (fs_IF) of the service frequency into a service frequency (fs) signal, amplifies it, and transmits it to the multiplexer (510). In addition, the up converter (523) up-converts the intermediate frequency signal (fs_IF) of the service frequency into a signal of the first frequency (f1), amplifies it, and outputs it to the multiplexer (510). The multiplexer (510) outputs the service frequency (fs) signal and the signal of the first frequency (f2).

[0088] FIG. 5b is a diagram explaining the operation of a wireless relay device according to an embodiment of the present invention when the forward input frequency is the first frequency.

[0089] The operation of the wireless relay device (500) of FIG. 5b may correspond to the operation of the second relay device (420) and the fourth relay device (440) whose input frequency is the first frequency (f1) in FIG. 4a.

[0090] When a signal input through a multiplexer (MUX) (570) is a signal of a first frequency (f1), a down converter (561) down-converts the signal of the first frequency (f1) to an intermediate frequency (IF) and then outputs a signal of an intermediate frequency signal (f 1_IF) containing only the signal component of the first frequency (f1) using a channel filter. The intermediate frequency signal (f 1_IF) of the first frequency output from the down converter (561) is input to a distributor (530). The distributor (530) transmits the signal to two up converters (521, 523).

[0091] The up converter (521) up-converts the intermediate frequency signal (f1_IF) of the first frequency into a service frequency (fs) signal, amplifies it, and transmits it to the multiplexer (510). In addition, the up converter (523) up-converts the intermediate frequency signal (f1_IF) of the first frequency into a signal of the second frequency (f2), amplifies it, and outputs it to the multiplexer (510). The multiplexer (510) outputs the service frequency (fs) signal and the signal of the second frequency (f2).

[0092] FIG. 5c is a diagram explaining the operation of a wireless relay device according to an embodiment of the present invention when the forward input frequency is a second frequency.

[0093] The operation of the wireless relay device (500) of FIG. 5c may correspond to the operation of the third relay device (430) whose input frequency is the second frequency (f2) in FIG. 4a.

[0094] When a signal input through a multiplexer (MUX) (570) is a signal of a second frequency (f2), a down converter (561) down-converts the signal of the second frequency (f2) to an intermediate frequency (IF) and then outputs a signal of an intermediate frequency signal (f2_IF) containing only the signal component of the second frequency (f2) using a channel filter. The intermediate frequency signal (f2_IF) of the second frequency output from the down converter (561) is input to a distributor (530). The distributor (530) transmits the signal to two up converters (521, 523).

[0095] The up converter (521) up-converts the intermediate frequency signal (f2_IF) of the second frequency into a service frequency (fs) signal, amplifies it, and transmits it to the multiplexer (510). In addition, the up converter (523) up-converts the intermediate frequency signal (f2_IF) of the second frequency into a signal of the first frequency (f1), amplifies it, and outputs it to the multiplexer (510). The multiplexer (510) outputs the service frequency (fs) signal and the first frequency (f1) signal.

[0096] FIG. 6A is a diagram explaining the operation of a wireless relay device according to an embodiment of the present invention when the reverse input frequency is the service frequency and the first frequency.

[0097] The operation of the wireless relay device (500) of FIG. 6a may correspond to the operation of the third wireless relay device (430) and the first relay device (410) in FIG. 4b, where the frequency of the input signal is the service frequency (fs) and the first frequency (f1).

[0098] The signal of the service frequency (fs) input to the multiplexer (510) is transmitted to the down converter (522), and the down converter (522) frequency-down converts the signal of the service frequency (fs) to an intermediate frequency (IF), and uses a channel filter to pass only the signal of the service frequency component, thereby outputting a signal of the intermediate frequency (fs_IF) of the service frequency. Thereafter, the signal of the intermediate frequency (fs_IF) of the service frequency is transmitted to the up converter (562) through the combiner (540).

[0099] Meanwhile, the signal of the first frequency (f1) input through the multiplexer (502) is transmitted to the down converter (524). The down converter (524) down-converts the signal of the first frequency (f1) to an intermediate frequency (IF), and outputs a signal of the intermediate frequency (f1_IF) of the first frequency by passing only the signal of the first frequency (f1) component through a channel filter. Thereafter, the signal of the intermediate frequency (f1_IF) of the first frequency is transmitted to the up converter (562) through the combiner (540).

[0100] The up converter (562) frequency-upconverts the intermediate frequency (fs_IF) signal of the service frequency and the intermediate frequency (f1_IF) signal of the first frequency into signals of the second frequency (f2), amplifies them, and outputs them to the multiplexer (570). If the output signal of the wireless relay device (500) is directly transmitted to the base station, that is, if the wireless relay device (500) corresponds to the first relay device (410) of FIG. 4B, the up converter (562) frequency-upconverts the intermediate frequency (fs_IF) signal of the service frequency and the intermediate frequency (f1_IF) signal of the first frequency into signals of the service frequency (fs), amplifies them, and outputs them to the multiplexer (570).

[0101] The multiplexer (570) outputs a signal of the second frequency (f2) or a signal of the service frequency (fs).

[0102] FIG. 6b is a diagram explaining the operation of a wireless relay device according to an embodiment of the present invention when the reverse input frequency is a service frequency and a second frequency.

[0103] The operation of the wireless relay device (500) of FIG. 6a may correspond to the operation of the fourth wireless relay device (440) and the second relay device (420) in FIG. 4b, where the frequency of the input signal is the service frequency (fs) and the second frequency (f2).

[0104] The signal of the service frequency (fs) input to the multiplexer (510) is transmitted to the down converter (522), and the down converter (522) frequency-down converts the signal of the service frequency (fs) to an intermediate frequency (IF), and uses a channel filter to pass only the signal of the service frequency component, thereby outputting a signal of the intermediate frequency (fs_IF) of the service frequency. Thereafter, the signal of the intermediate frequency (fs_IF) of the service frequency is transmitted to the up converter (562) through the combiner (540).

[0105] Meanwhile, the signal of the second frequency (f2) input through the multiplexer (502) is transmitted to the down converter (524). The down converter (524) down-converts the signal of the second frequency (f2) to an intermediate frequency (IF), and outputs a signal of the intermediate frequency (f2_IF) of the second frequency by passing only the signal of the second frequency (f2) component through a channel filter. Thereafter, the signal of the intermediate frequency (f2_IF) of the second frequency is transmitted to the up converter (562) through the combiner (540).

[0106] The up converter (102) up-converts the signal of the intermediate frequency (fs_IF) of the service frequency and the signal of the intermediate frequency (f2_IF) of the second frequency into a signal of the first frequency (f1), amplifies the signal, and outputs it to the multiplexer (570).

[0107] The multiplexer (570) outputs a signal of the first frequency (f2).

[0108] Meanwhile, although there may be implementation differences depending on whether the duplex method used in the wireless communication system is Frequency Division Duplex (FDD) or Time Division Duplex (TDD), the basic structure of the wireless relay device is the same as described above in both cases. Furthermore, the operation of the wireless relay device according to the embodiment of the present invention can be implemented in the same manner not only in the analog domain but also in the discrete time domain.

[0109] The wireless relay method described in FIGS. 4A and 4B, 5A to 5D, and 6A and 6B so far assumes that two link frequencies (e.g., f1, f2) are used in the wireless communication system. In this case, if the frequency of the signal input to the wireless relay device is the service frequency (fs), the wireless relay device outputs a signal of the service frequency (fs) and a signal of the frequency of one of the two link frequencies (e.g., f1 or f2). If the frequency input to the wireless relay device is one of the link frequencies (e.g., f1), the wireless relay device outputs a signal of the service frequency (fs) and a signal of the frequency of another link frequency (f2) excluding the input link frequency.

[0110] If three or more link frequencies (e.g., f1, f2, f3) are used in the wireless communication system, and the frequency of a signal input to the wireless repeater is a service frequency (fs), the wireless repeater outputs a signal of the service frequency (fs) and a signal of the frequency of one of the three link frequencies (e.g., f1, f2, or f3). If the frequency input to the wireless repeater is one of the link frequencies (e.g., f1), the wireless repeater outputs a signal of the service frequency (fs) and a signal of the frequency of one of the link frequencies other than the input link frequency (e.g., f2).

[0111] Below, the operation flow of a wireless relay device according to an embodiment of the present invention is described.

[0112] FIG. 7 is a drawing illustrating the operation of a wireless relay device that receives a forward signal according to an embodiment of the present invention.

[0113] Referring to Fig. 7, a wireless relay device receives a forward (=downlink) input signal transmitted from a base station (S710). The wireless relay device checks the frequency of the input signal (S720).

[0114] If the frequency of the input signal is the service frequency, the wireless repeater outputs a signal of the service frequency and a signal of one of the link frequencies (S730). For example, if there are two link frequencies (f1, f2), the wireless repeater can select one of the frequencies f1 or f2 and output a signal of the selected link frequency.

[0115] If the frequency of the input signal is one of a plurality of preset link frequencies, the wireless repeater outputs a signal of the service frequency and a signal of one of the link frequencies excluding the input link frequency (S740). For example, if there are two link frequencies (f1, f2), the wireless repeater can select one of the frequencies f1 or f2 and output a signal of the selected link frequency. If there are three link frequencies (f1, f2, f3), the wireless repeater can select one of the frequencies f1, f2, or f3 and output a signal of the selected link frequency.

[0116] FIG. 8 is a drawing illustrating the operation of a wireless relay device that receives a reverse signal according to an embodiment of the present invention.

[0117] Referring to Figure 8, a wireless relay device receives a reverse (=uplink) input signal transmitted from a terminal and a signal of a link frequency transmitted by another wireless relay device (S810). At this time, the frequency of the signal transmitted by the terminal is a signal of the service frequency (fs).

[0118] A wireless relay device determines whether it is the last relay device relaying signals to a base station (S820). If the output signal of the wireless relay device is transmitted directly to the base station without being relayed by another wireless relay device, the wireless relay device becomes the last wireless relay device.

[0119] Whether or not it is the last relay station can be determined based on the frequency of the downlink signal input to the wireless relay station. That is, if the frequency of the downlink signal input to the wireless relay station is the service frequency (fs), the wireless relay station can determine that it is the last wireless relay station. The frequency of the downlink signal input to the wireless relay station being the service frequency (fs) means that the downlink signal is a signal received directly from the base station. Therefore, the uplink signal will also be transmitted directly to the base station without relaying by other wireless relay stations.

[0120] If it is determined that it is not the last wireless relay device, the wireless relay device converts the input signal of the service frequency (fs) and the input signal of the link frequency into other link frequencies excluding the input link frequency and outputs signals (S830). For example, if there are two link frequencies (f1, f2), and the signal of the service frequency (fs) and the signal of the link frequency f1 are input to the wireless relay device, the wireless relay device converts the input signal of the service frequency (fs) and the signal of the link frequency (f1) into a signal of the link frequency f2 other than f1 and outputs the signal. As another example, if there are three link frequencies (f1, f2, f3), and the signal of the service frequency (fs) and the signal of the link frequency f1 are input to the wireless relay device, the wireless relay device converts the input signal of the service frequency (fs) and the signal of the link frequency f1 into a signal of f2 or f3, which is one of the link frequencies (f2, f3) other than f1, and outputs the signal.

[0121] If it determines that it is the last wireless repeater, the wireless repeater outputs the input signal of the service frequency (fs) and the input signal of the link frequency as signals of the service frequency, respectively.

[0122] FIG. 9 is a drawing explaining the configuration of a wireless relay device according to an embodiment of the present invention.

[0123] Referring to FIG. 9, a wireless relay device (900) includes a communication unit (910), a processor (920), and a storage unit (930).

[0124] The storage unit (930) can store information, commands, etc. necessary for the operation of the wireless relay device (900).

[0125] The communication unit (910) may include a configuration such as that shown in FIGS. 5A to 5D and FIGS. 6A and 6B, and receives a signal from a base station, a terminal, or another wireless relay device, and frequency converts and amplifies the input signal to generate an output signal.

[0126] The processor (920) controls the overall operation of the wireless relay device (900). In particular, it can control the communication unit (910) according to an embodiment of the present invention. Specifically, when the processor (920) receives a forward input signal transmitted from a base station, it checks the frequency of the input signal. If the frequency of the input signal is a service frequency, the processor (920) controls the communication unit (910) to output a signal of the service frequency and one of the link frequencies. If the frequency of the input signal is one of the link frequencies, the processor (920) controls the communication unit (910) to output a signal of the service frequency and a signal of one of the link frequencies excluding the input link frequency.

[0127] In addition, when the processor (920) receives a reverse input signal transmitted from the terminal and a signal of a link frequency transmitted from another wireless device, the processor (920) determines whether the wireless relay device (900) is the last relay device relaying the signal to the base station. If the output signal of the wireless relay device (900) is directly transmitted to the base station without relaying by another wireless relay device, the wireless relay device (900) becomes the last wireless relay device.

[0128] If it is determined that it is not the last wireless relay device, the processor (920) controls the communication unit (910) so that the input signal of the service frequency (fs) and the input signal of the link frequency are converted to signals other than the input link frequency, respectively, and outputs signals. If it is determined that it is the last wireless relay device, the processor (920) controls the communication unit (910) so that the input signal of the service frequency (fs) and the input signal of the link frequency are output as signals of the service frequency, respectively.

[0129] The methods proposed in this specification may also be performed by an apparatus configured to control the wireless relay device, which includes, in addition to the communication device, at least one computer-readable recording medium containing instructions based on being executed by at least one processor, and one or more processors and one or more memories executable by the one or more processors and storing the instructions, wherein the one or more processors execute the instructions to perform the methods proposed in this specification.

[0130] The claims set forth in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined and implemented as a device, and the technical features of the device claims of this specification may be combined and implemented as a method. Furthermore, the technical features of the method claims and the technical features of the device claims of this specification may be combined and implemented as a device, and the technical features of the method claims and the technical features of the device claims of this specification may be combined and implemented as a method.

Claims

1. In the operating method of a wireless relay device, (a) a step of receiving a downlink signal; (b) a step of determining the frequency of the outputted first signal as one of a plurality of preset link frequencies different from the frequency of the downlink signal; and (c) A method of operating a wireless relay device, comprising the step of outputting a first signal having the determined link frequency and a second signal having the service frequency of the base station by using the input downlink signal.

2. In paragraph 1, step (b) is, An operating method of a wireless relay device, characterized in that if the frequency of the input downlink signal is the service frequency, the frequency of the first signal is determined as one of the plurality of preset link frequencies.

3. In the second paragraph, step (c) is, A step of converting a downlink signal of the above service frequency into a signal of an intermediate frequency; A step of frequency up-converting the converted intermediate frequency signal into a second signal of the service frequency; and A method of operating a wireless relay device, comprising the step of frequency up-converting a signal of the converted intermediate frequency into a first signal of the determined link frequency.

4. In paragraph 1, step (b) is, A method for operating a wireless relay device, characterized in that if the frequency of the input downlink signal is one of the plurality of preset link frequencies, the frequency of the first signal is determined as one of the link frequencies other than the frequency of the input downlink signal among the plurality of preset link frequencies.

5. In paragraph 4, step (c) is, A step of converting the input downlink signal into an intermediate frequency signal; A step of frequency up-converting the converted intermediate frequency signal into a second signal of the service frequency; and A method of operating a wireless relay device, comprising the step of frequency up-converting a signal of the converted intermediate frequency into a first signal of the determined link frequency.

6. In a wireless relay device, A communication unit for receiving a downlink signal; and A wireless relay device comprising a processor that determines the frequency of a first signal to be output as one of a plurality of preset link frequencies different from the frequency of the downlink signal, generates a first signal having the determined link frequency and a second signal having a service frequency of a base station using the input downlink signal, and outputs the first signal and the second signal through the communication unit.

7. In the 6th paragraph, the processor, A wireless relay device, which determines the frequency of the first signal as one of the plurality of preset link frequencies if the frequency of the input downlink signal is the service frequency.

8. In paragraph 7, the communication unit, A down converter that converts a downlink signal of the above service frequency into a signal of an intermediate frequency; A first up-converter for frequency-upconverting the converted intermediate frequency signal into a second signal of the service frequency; and A wireless relay device comprising a second up-converter for frequency up-converting a signal of the converted intermediate frequency into a first signal of the determined link frequency.

9. In paragraph 6, the processor, A wireless relay device, wherein if the frequency of the input downlink signal is one of the plurality of preset link frequencies, the frequency of the first signal is determined as one of the plurality of preset link frequencies other than the frequency of the input downlink signal.

10. In paragraph 9, the communication unit, A down converter that converts the input downlink signal into an intermediate frequency signal; A first up-converter for frequency-upconverting the converted intermediate frequency signal into a second signal of the service frequency; and A wireless relay device comprising a second up-converter for frequency up-converting a signal of the converted intermediate frequency into a first signal of the determined link frequency.

11. In the operating method of a wireless relay device, (a) a step of receiving a first uplink signal of a service frequency of a base station and a second uplink signal of a first link frequency, which is one of a plurality of preset link frequencies relayed from another relay device; (b) determining the frequency of the output signal based on whether the wireless relay device is the last wireless relay device; and (c) a step of generating an output signal of the determined frequency using the first uplink signal and the second uplink signal, A method of operating a wireless relay device, wherein the last wireless relay device directly transmits an output signal of the wireless relay device to a base station without relaying it through another wireless relay device.

12. In paragraph 11, step (b) is, A method of operating a wireless relay device, comprising the step of determining the frequency of the output signal as the service frequency if the wireless relay device is the last wireless relay device.

13. In paragraph 12, step (c) is, A step of converting the first uplink signal into a first intermediate signal of intermediate frequency; A step of frequency up-converting the first intermediate signal into a signal of the service frequency; A step of converting the second uplink signal into a second intermediate signal of intermediate frequency; and A method of operating a wireless relay device, comprising the step of frequency up-converting the second intermediate signal into a signal of the service frequency.

14. In paragraph 11, step (b) is, A method of operating a wireless relay device, comprising the step of determining the frequency of the output signal as a second link frequency other than the first link frequency among the plurality of preset link frequencies, if the wireless relay device is not the last wireless relay device.

15. In paragraph 14, step (c) is, A step of converting the first uplink signal into a first intermediate signal of intermediate frequency; A step of frequency up-converting the first intermediate signal into a signal of the determined second link frequency; A step of converting the second uplink signal into a second intermediate signal of intermediate frequency; and A method of operating a wireless relay device, comprising the step of frequency up-converting the second intermediate signal into a signal of the determined second link frequency.

16. In a wireless relay device, A communication unit receiving a first uplink signal of a service frequency of a base station and a second uplink signal of a first link frequency, which is one of preset link frequencies relayed from another relay device; and A processor is included that determines the frequency of an output signal based on whether the wireless relay device is the last wireless relay device, generates an output signal of the determined frequency using the first uplink signal and the second uplink signal, and outputs the output signal through the communication unit. The above last wireless relay device is a wireless relay device that directly transmits the output signal of the wireless relay device to the base station without relaying it through another wireless relay device.

17. In paragraph 16, the processor, A wireless repeater device, wherein the frequency of the output signal is determined as the service frequency if the wireless repeater device is the last wireless repeater device.

18. In paragraph 17, the communication unit, A first down converter for converting the first uplink signal into a first intermediate signal of intermediate frequency; An up converter for frequency up-converting the first intermediate signal into a signal of the service frequency; A second down converter for converting the second uplink signal into a second intermediate signal of intermediate frequency; and A wireless repeater device, comprising an up-converter for frequency-upconverting the second intermediate signal into a signal of the service frequency.

19. In paragraph 16, the processor, A wireless relay device, wherein if the wireless relay device is not the last wireless relay device, the frequency of the output signal is determined as a second link frequency, not the first link frequency, among the plurality of preset link frequencies.

20. In paragraph 19, the communication unit, A first down converter for converting the first uplink signal into a first intermediate signal of intermediate frequency; An up converter for frequency up-converting the first intermediate signal into a signal of the determined second link frequency; A second down converter for converting the second uplink signal into a second intermediate signal of intermediate frequency; and A wireless repeater device, comprising an up-converter for frequency up-converting the second intermediate signal into a signal of the determined second link frequency.

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