JP6629396B2 - Apparatus and method in TDD wireless communication - Google Patents

Description

  The present technology relates generally to wireless communications, and more particularly to wireless network entities and methods for improving filtering performance in time division duplex wireless communication systems.

  Cellular technology standardized by the Third Generation Partnership Program (3GPP) is the most widespread in the world. A new step being researched and developed in the 3GPP is the 3G evolution to an evolving radio access technology called Long Term Evolution (LTE). According to LTE, different communication modes, such as frequency division duplex (FDD), time division duplex (TDD), and half duplex, are available for wireless nodes in a cellular network.

  According to the TDD wireless communication system, the uplink communication and the downlink communication between the wireless base station and the user equipment use the same frequency channel (ie, carrier), but separate transmission and reception. Receive and transmit in different non-overlapping time lots.

  According to FIG. 2, a partial or complete block diagram of a typical wireless network entity for TDD communication is shown. The radio network entity may be a user equipment or a radio base station in a TDD radio communication system. Further, a wireless network entity may be part of, internal to, or external to a user equipment or a wireless base station in a TDD wireless communication system. Since reception and transmission in a TDD wireless communication system use the same frequency channel, a shared TDD filter 27 is used for both transmitted and received signals.

  In fact, the filtering requirements for transmitting and receiving signals are different, and the filtering requirements may change if the scenario changes. In order to satisfy different requirements with one shared TDD filter, the worst case of out-of-band attenuation needs to be considered, which increases the insertion loss of the filter and results in unnecessary system performance degradation. It is invited.

  Therefore, it is an object to solve at least one of the above-mentioned problems.

  According to one aspect of an embodiment, there is provided a wireless network entity for improving filtering performance in a time division duplex (TDD) wireless communication system, comprising: A first filter configured to perform a first type of filtering for a signal transmitted to or received from a device in a wireless communication system over a wireless interface using a filtering requirement And a second filter configured to perform a second type of filtering for the signal transmitted to the device, with the additional common filtering requirement in addition to the satisfied common filtering requirement. Fulfilled common filtering requirements, plus additional filtering for reception Using Taringu requirements, having a third filter configured to perform a third type of filtering for the received signal from the device.

  According to another aspect of the embodiments, there is provided a method for a wireless network entity for improving filtering performance in a time division duplex (TDD) wireless communication system, the method comprising: Performing a second type of filtering for signals transmitted to devices in a wireless communication system over a wireless interface using additional filtering requirements for transmission in addition to the common filtering requirements performed. , A signal of a first type for a signal transmitted to or received from a device in a wireless communication system via a wireless interface using a common filtering requirement satisfied for transmission and reception. Performing filtering.

  The first filter and the second filter constitute a separated transmission filter, and the first filter and the third filter constitute a separated reception filter. Overall, the three filters need not be arranged together, but may be arranged in a distributed manner to be more space efficient. All three filters are less costly than a single shared filter in the prior art due to reduced power handling (processing) requirements. Because there is a separate path for the transmitted signal, the transmit filter also does not need to sacrifice insertion loss (IL) to meet the blocking requirements of the receiver. Further, the reduction of the insertion loss IL for the transmission filter will contribute to thermal efficiency and power efficiency. Because there is a separate path for the received signal, the receive filter does not have to sacrifice its insertion loss IL to meet the transmit spurious emission requirements, and the reduction in insertion loss IL for the receive filter is a noise figure. (Noise figure) and receiver sensitivity. Since the third filter is relieved from power handling requirements and passive (passive) intermodulation requirements, it may be possible to provide more flexibility in implementing the third filter. If more attenuation is required compared to a conventional TDD filter, the transmit filter will have better power handling performance.

The present technology will be described by way of example based on embodiments with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating an environment in which the embodiment is implemented. FIG. 2 is a diagram of a wireless network entity for TDD communication in the prior art. FIG. 3 is a diagram illustrating attenuation (allocation) allocation of a wireless network entity for TDD communication in the prior art. FIG. 4 is a diagram of a wireless network entity for TDD communication according to some embodiments of the present invention. FIG. 5 is a diagram illustrating attenuation allocation of a wireless network entity for TDD communication according to another embodiment of the present invention. FIG. 6 is a diagram of a wireless network entity for TDD communication according to another embodiment of the present invention. FIG. 7 is a diagram illustrating a part of a wireless network entity for TDD communication according to an embodiment of the present invention. FIG. 8 is a diagram illustrating a part of a wireless network entity for TDD communication according to another embodiment of the present invention. FIG. 9 is a flowchart illustrating a method performed in a wireless network entity for TDD communication according to an embodiment of the present invention.

  Embodiments will be described in detail below with reference to the accompanying drawings showing the embodiments. The following embodiments can be implemented in many different forms and should not be construed as limited to only the following embodiments. The elements of the drawing need not be scaled relative to each other. Similar elements are generally numbered the same.

  The terms used herein are used only to describe a particular embodiment and are not intended to be limiting. As used herein, the singular forms "a", "an", and "the" are intended to include the plural unless the context clearly dictates otherwise. As used herein, the terms “comprising,” “having,” “including,” and / or “including” refer to the recited feature, integer, step, action, element, and / or It is used to identify the presence of a component, and does not exclude the presence or addition of one or more other features, integers, steps, acts, elements, components and / or combinations thereof.

  Unless defined otherwise, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood. It is further to be understood that the applications used herein have meanings consistent with the meaning in this specification and the description in the related art, and are, unless explicitly defined herein, ideally or in any form There is no need to be understood with a typical feeling.

  Embodiments will be described below with reference to the drawings.

  In the following, embodiments are described in the context of a TDD wireless communication system. However, such descriptions are illustrative only and not rigorous, and the embodiments also apply appropriately to other types of existing or future networks.

  FIG. 1 is a diagram illustrating an environment in which the embodiment is implemented.

  TDD wireless communication system 100 includes a plurality of radio base stations (RBS) 101. For example, for simplicity, four RBSs 101 are shown.

  Here, the connection between the RBSs 101 can be implemented by wire, wireless, or a combination thereof.

  Further, those skilled in the art will understand that the wireless base station 101 is often referred to in the art as a base station, a macro base station, a femto base station, a Node B, a B-node or an eNodeB, and furthermore, the user equipment ( It will also be appreciated that other transceivers or wireless communication stations used to communicate with the UE (UE) 102 may be referred to.

  In the illustrated environment, for simplicity, each RBS 101 is shown as serving one cell. Each cell is represented by a circle surrounding each corresponding RBS 101. However, those skilled in the art will appreciate that the RBS 101 functions for communication over the air interface for more than one cell. For example, two cells may use resources that exist at the same RBS site.

  A UE, such as the UE 102 shown in FIG. 1, communicates with one or more cells or one or more RBSs 102 over a radio or air interface. For simplicity, there is one set of UEs, two sets of UEs, three sets of UEs, and four sets of UEs in each of the cells. Different numbers of UEs are served by the cells, and the number of UEs served by different cells need not be identical to one another. As used herein, the term "UE" can refer to any type of device capable of communicating over a communications network, and performing voice and / or data communications over a wireless network. "Cellular" telephones), laptop computers with mobile termination, etc., and are therefore portable, pocket, handheld devices such as mobile phones, smartphones, personal digital assistants (PDAs), etc. It may be a desktop device, a laptop device, an in-vehicle device, or another device such as a meter device, a home appliance device, a medical device device, or a multimedia device.

  According to the wireless communication system of TDD, uplink communication and downlink communication between the RBS and the UE use the same frequency channel (ie, carrier), but different times to separate transmission and reception. Reception and transmission occur in different timelots that use slots, ie, do not overlap.

  FIG. 2 is a block diagram of a typical wireless network entity for TDD communication in the prior art. The wireless network entity may be the UE 102 or the RBS 101 in the TDD wireless communication system 100. Further, the wireless network entity may be part of, be internal to, or external (connected by wire) in the UE 102 or RBS 101 in a TDD wireless communication system. Since reception and transmission in a TDD wireless communication system use the same frequency channel, a shared TDD filter 27 configured for both signals transmitted to and received from devices in the TDD wireless communication system 100 is provided. used. The wireless network entity includes an antenna 28, which is also designed to transmit or receive electromagnetic (eg, wireless) waves, for converting electrical signals to electromagnetic waves, and for converting electromagnetic waves to electrical signals. Also referred to as aerial or transducer. The radio network entity further includes a circulator 26 which serves to separate the transmit and receive paths, a 50 ohm resistor 29 for transmitting the transmit leakage signal, and a ground for the transmit slot and a receiver for the receiver slot. A TDD switch 25 configured to connect to (RX) 22 and a power amplifier (PA) 23 configured to perform power amplification on a signal to be transmitted via antenna 28. A low noise amplifier (LNA) 24 configured to perform power amplification on the signal received via antenna 28, and in particular to boost the desired signal power with as little noise and distortion as possible. And appropriate transmission according to a wireless communication protocol in the TDD wireless communication system 100. It has a transmitter (TX) 21 that is configured to form a signal for, and RX22 for proper reception in accordance with the wireless communication protocol in a TDD wireless communication system 100. In the art, the part between antenna 28 and RX 22 is called the receiver front end, and the part between antenna 28 and TX 21 is called the transmitter back end.

  Reducing out-of-band spurious emissions for signal transmission is a mandatory requirement, while reducing out-of-band blocking for signal reception is also a mandatory requirement. For example, in one scenario, for signal transmission, reducing spurious emissions on the higher frequency side of the operating band needs to be considered primarily, while lower frequencies in the operating band The required attenuation on the side is relatively slower. For signal reception, blocking reduction requires tough filter attenuation on the lower frequency side of the operating band, while relatively higher attenuation is required on the higher frequency side. In the upper part of FIG. 3, the dashed line indicates the pass band (pass band) of the filtering requirement in the frequency domain for the transmission signal, and the dotted line indicates the pass band (pass band) of the filtering requirement in the frequency domain for the received signal. ing. Embodiments in the present disclosure refer to this scenario for illustrative, but not limiting, purposes.

  It should be noted that such scenarios are for illustration purposes only, rather than limiting. According to another scenario, for signal transmission, the reduction of spurious emissions on the lower side of the operating band needs to be mainly considered, and the attenuation on the higher side of the operating band is relatively more relaxed. For signal reception, reducing blocking requires tighter filter attenuation at the higher end of the operating band, but the attenuation required at the lower end is relatively relaxed.

  To meet filtering requirements using a common filter for both signal transmission and signal reception, severe attenuation is applied to both signal transmission and signal reception at both the low and high sides It must be. This means that on the lower side, severe attenuation not required for signal transmission must be applied to the signal, and on the higher side, severe attenuation not required for signal reception must be applied to the signal. Means you have to. As a result, the pass band of the common filter (common filter) is formed as shown in the lower part of FIG.

  In addition, the filtering requirements for signal reception on the high side of the operating band shown in FIG. 3 are specified to satisfy all potential and fatal blocking reduction requirements, and this blocking is collocation (co-located). ) Or due to coexistence (coexistence) from other sources. For some or most TDD wireless communications, there may be no blocking interference due to co-location or coexistence, ie, the filtering requirements for receiving the signals shown in FIG. This means that side attenuation is not always required.

  FIG. 4 is a block diagram of a wireless network entity for TDD communication according to some embodiments of the present invention. The radio network entity may be a UE or RBS in a TDD radio communication system. Further, the wireless network entity may be part of, be internal to, or external (preferably hardwired) of UE 102 or RBS 101 in TDD wireless communication system 100. The wireless network entity includes an antenna 28, a circulator 26, a dual path switch 45, a power amplifier (PA) 23, a low noise amplifier (LAN) 24, a transmitter 21, a receiver 22, a filter 142, , A filter 2 43, and a filter 3 44.

  The antenna 28 is a transducer that transmits or receives a signal in the form of an electromagnetic wave and converts an electric signal into an electromagnetic wave or converts an electromagnetic wave into an electric signal. In most cases, the antenna 28 is shared for both transmission and reception according to the reciprocal principle of the antenna. However, this does not preclude scenarios where two antennas are configured for transmission and reception respectively. The circulator 26 serves to separate the transmit and receive paths within the wireless network entity and can be replaced by a switch that performs a similar function. The switch 45 is configured to route the transmit leakage signal to the 50 ohm resistor 29 and to ground in the transmit slot or to connect to the receiver (RX) 22 in the receiver slot. Power amplifier (PA) 23 is configured to perform power amplification on a signal to be transmitted via antenna 28. A low noise amplifier (LNA) 24 is configured to perform power amplification on the signal received via antenna 28, and in particular to boost the desired signal power with as little noise and distortion as possible. Have been. The transmitter (TX) 21 is configured to form a signal for appropriate transmission according to a wireless communication protocol in the TDD wireless communication system 100. The receiver 22 is configured for appropriate reception according to a wireless communication protocol in the TDD wireless communication system 100. The antenna 28, the circulator 26, the dual path switch 45, the PA 23, the LNA 24, the transmitter 21, and the receiver 22 can be applied to the conventional rules, and these elements can be easily purchased in the market. It would be possible.

  Filter 142 may be used for signals transmitted to or received from devices in wireless communication system 100 via antenna 28 using common filtering requirements satisfied for transmission and reception. Is configured to perform the first type of filtering. Filter 243 is configured to perform a second type of filtering for the signal to be transmitted to the device, with additional filtering requirements for transmission in addition to the fulfilled common filtering requirements. . Filter 344 is configured to perform a third type of filtering for signals received from the device, with additional filtering requirements for reception in addition to the fulfilled common filtering requirements. . Note that the device may be the UE 102 or the RBS 101, or may be a device in the hierarchically structured wireless communication system illustrated in FIG. 1, and the wireless network entity is the UE 102 or the inside of the UE 102. Or belongs to the outside of the UE 102, the device is the RBS101, and the radio network entity is the RBS101, or belongs to the inside of the RBS101, or belongs to the outside of the RBS101. Sometimes, the device is UE 102.

  In the transmission slot, a signal to be transmitted to a device in the wireless communication system via the antenna 28 is generated by the TX 21, and the generated signal is transmitted to the PA 23, the filter 243, the circulator 26, the filter 1 until reaching the antenna 28. 42 in order, and is converted into electromagnetic waves in the air. Meanwhile, the switch 45 sends a leakage signal, which is part of the signal to be transmitted, to the 50 ohm resistor 29 and to ground. In the receive slot, the signal is received through antenna 28 and passes through filter 142, circulator 26, switch 45, filter 344, and LNA 24 in that order, up to RX22.

  In the embodiment shown in FIG. 4, the filter 344 carries a low power radio frequency signal, and thus does not need to meet high power handling or passive intermodulation requirements. Thus, the filter 344 has higher implementation flexibility, for example, in one scenario, a high Q value is a primary concern, and thus a flexible cavity size ensures such a Q value In other scenarios, miniaturization is a major concern, and in other scenarios more types of resonators, such as microwave planar circuit resonators, will be implemented on PCBs. Whatever is feasible can be used, which greatly contributes to the miniaturization of the filter 344, has a penalty at low Q of the resonator, and in other scenarios a medium size and medium Are required, so these implementations may be specifiable. This is the same for the filter 243.

  It is well known that quality factor (or Q factor) refers to a measure of the relative bandwidth of a resonant system. The Q value is a dimensionless parameter that indicates how much the oscillator or resonator is underdamped, or equivalently, how the bandwidth of the resonator relative to the center frequency of the resonator is characterized. . In general, high-Q filters do a good job of filtering out signals that lie close to the desired band, and also have low insertion loss.

  Those skilled in the art will appreciate that switch 45 can be replaced by a suitable set of voltage controlled diodes that perform a similar function.

  Those skilled in the art will appreciate that the signal received through the antenna 28 may pass through the filter 142, the circulator 26, the LNA 24, the switch 45, and the filter 344 in sequence to the RX 22. In such a case, LNA 24 is located between circulator 26 and switch 45 (not shown).

  By arranging the LNA 24 in this manner, the present embodiment is advantageous in that the noise figure of the receiver front end of the wireless network entity can be improved. According to those skilled in the art, the LNA 24 may be blocked by strong signals, such as strong interference from other sources due to co-location or coexistence, and therefore the performance of the LNA 24 of this embodiment may Understand that it relies on out-of-band rejection.

  FIG. 5 is a diagram illustrating attenuation allocation of a wireless network entity for TDD communication according to some embodiments of the present invention. As FIG. 5 shows, the common filter, Filter 142, provides the basic attenuation for both the transmit and receive paths, Att1 at frequency f1 and Att4 at frequency f4, respectively. It is necessary to meet. An additional transmit filter, filter 243, needs to provide the additional attenuation required only in the transmission path, which is the attenuation ATT_tx2 at frequency f3. ATT_tx2 is obtained by subtracting the attenuation ATT_tx1 of the common filter from Att3 at the frequency f3. An additional receive filter, filter 344, needs to provide the additional attenuation required only in the receive path, which is the attenuation ATT_rx3 at frequency f2. ATT_rx3 is obtained by subtracting the attenuation ATT_rx1 of the common filter from Att2 at the frequency f2.

  As is known in the art, attenuation requirements are positively related to the required number of filter poles. Since unnecessary attenuation is avoided, unnecessary poles (poles) are reduced, that is, the number of required poles is reduced, and insertion loss caused by unnecessary poles is also avoided.

  FIG. 6 is a block diagram of a wireless network entity for TDD communication according to some embodiments of the present invention. According to an embodiment, in addition to the elements shown in FIG. 4, a bypass unit 61 of FIG. 6 is provided, the bypass unit 61 being a switch 2 62 which is a dual-pass switch and a switch 1 63 which is a triple-pass switch. Is configured based at least on the connection between Therefore, there are two routes for the received signal coming from the circulator 26. The first is a filtering route in which a received signal from the circulator 26 passes through the switch 163, the filter 344, and the switch 262 in that order, and reaches the LNA 24. The second is a bypass route in which a received signal from the circulator 26 passes through the switch 163 and the switch 362 in order, reaches the LNA 24, and bypasses the filter 344.

  According to another embodiment, it can be assumed that strong interference, such as interference from neighboring RBSs, is almost stable at a certain time. Sufficient non-transmission periods are available for interference detection to determine the switching between the filtering route and the bypass route in the receiving path. The wireless network entity further controls an operation of an interference detector 65 connected to the antenna 28 and configured to detect the received interference, and a switch 61 based on the detected interference. It has a controller 64 configured to control the state of 63 and switch 262.

  According to yet another embodiment, the interference detector 65 further includes a detection filter 66 and a power detector 67. A detection filter 66 is connected to the antenna 28 and is configured to detect interference when the antenna 28 is not performing transmission, and a power detector 67 is configured to determine a power level of the interference. ing. Further, the controller 64 switches between the bypass route and the filtering route, i.e., if the power level of the interference is below a predetermined threshold, the controller 64 activates the bypass route and the power level of the interference is below the predetermined threshold. If not, it is configured to activate the filtering route, which is realized by controlling the state of the switch 1 63 and the switch 2 62.

  In yet another embodiment, the wireless network entity has a gain compensator 68 configured to perform gain compensation between the bypass route and the filtering route. Further, the controller 64 is configured to notify the gain compensator 68 of the activation of the bypass route and the filtering route, that is, the start time information and the end time information of the transmission through the bypass route, and the transmission time through the filtering route. The transmitted start time information and end time information may be notified.

  Those skilled in the art will recognize that the signal received via the antenna 28 may be routed through the filter 142, the circulator 26, the LNA 24, the switch 1 63, the filter 3 44, the switch 2 62 to the RX 22 or It will be appreciated that the signal received via 28 passes through circulator 26, LNA 24, switch 1 63, and then directly adds switch 2 62 in turn, bypassing filter 344, to RX 22. There will be. In such a case, the LNA 24 is located between the circulator 26 and the switch 163, as shown in FIG.

  By arranging the LNA 24 in this manner, the present embodiment is advantageous in that the noise figure of the receiver front end of the wireless network entity can be improved. According to those skilled in the art, the LNA 24 may be blocked by strong signals, such as strong interference from other sources due to co-location or coexistence, and therefore the performance of the LNA 24 of the present embodiment may be Understand that we rely on outside arrest.

  Those skilled in the art will recognize that switch 163 and switch 262 can be replaced by a suitable set of voltage controlled diodes that perform similar functions. As FIG. 8 shows, Vctr1 81 activates a switch to activate and deactivate the bypass route. Vctr2 82 and Vctr3 83 actuate switches to activate and deactivate filtering routes.

  It should be understood that this or other arrangements described herein are merely exemplary. Other arrangements and elements (eg, elliptical low-pass filters to provide additional attenuation near the passband, circulators instead of switches, etc.) can be used in addition to or in place of those shown, Some elements may be omitted completely.

  The first filter 142 and the second filter 243 constitute a separated transmission filter, and the first filter 142 and the third filter 344 constitute a separated reception filter. As a whole, the three filters, Filter 1 42, Filter 2 43 and Filter 3 44, need not be located together, but may be distributed to be more space efficient. All three filters have lower power handling requirements and therefore lower cost than a single shared filter in the prior art. Because there is a separate path for the transmitted signal, the transmit filter also does not need to sacrifice insertion loss (IL) to meet the blocking requirements of the receiver 22. Further, the reduction of the insertion loss IL for the transmission filter will contribute to thermal efficiency and power efficiency. Because there is a separate path for the received signal, the receive filter does not have to sacrifice its insertion loss IL to meet the transmit spurious emission requirements, and the reduction in insertion loss IL for the receive filter is a noise figure. And will contribute to the improvement of reception sensitivity. Changes in the receive filter may be applied by activating or bypassing the third filter according to the power level of the interfering signal. Since the third filter 344 is relieved from power handling requirements and passive intermodulation requirements, more implementation flexibility for the third filter 344 could be provided. If more attenuation is required compared to a conventional TDD filter, the transmit filter will have better power handling performance.

  FIG. 9 is a flowchart illustrating a method performed in a wireless network entity for TDD communication according to some embodiments of the present invention.

  According to an embodiment, in step 918, a signal transmitted via antenna 28 to a device in TDD wireless communication system 100 arrives from TX 21 and passes through PA 23 for transmission and reception for that signal. , A second type of filtering is performed using additional filtering requirements for transmission, in addition to the common filtering requirements satisfied in step 920, and then in step 920 the additional transmission filter path shown in FIG. A first type of filtering is performed through the band and using the common filtering requirements that are met for transmission and reception for that signal, passing through the pass band of the common filter shown in FIG. I do.

  According to another embodiment, after a signal is received from a device of the wireless communication system via antenna 28, in step 902, a first type of filtering is performed using common filtering requirements that are met for transmission and reception. It is performed on that signal and passes through the passband of the common filter shown in FIG.

  In yet another embodiment, at step 906, interference from other sources due to co-location or coexistence is obtained. Interference can be obtained whenever the antenna 28 is not performing transmission, including idle periods and guard periods. Then, the power level of the interference is determined. If it is determined in step 910 that the power level is not below a predetermined threshold, then in step 912 the third type of filtering is performed using additional filtering requirements for reception in addition to the common filtering requirements to be met. Filtering is performed on the signal, passing through the passband of the additional receive filter shown in FIG.

  According to yet another embodiment, at step 914, time information as to whether to perform the third type of filtering is notified for gain compensation purposes, and at step 916, the third type of filtering is performed. Gain compensation between the signal by performing and the signal by not performing may be performed.

  As an example, in step 904 following step 902, low noise amplification may be performed on the received signal. As another example, low noise amplification may be performed on the received signal just before the received signal is processed by the receiver.

  Advantageously, in step 904 following step 902, low-noise amplification is performed on the received signal, which can improve the reception sensitivity.

  One skilled in the art will appreciate that steps 906, 908, 910, 914, 916 are not required.

  Filter 1 42 as the first filter and filter 2 43 as the second filter constitute a separated transmission filter, and filter 1 42 as the first filter and filter 3 44 as the third filter are separated reception filters. Is composed. As a whole, the three filters, Filter 1 42, Filter 2 43 and Filter 3 44, need not be located together, but may be distributed to be more space efficient. All three filters have lower power handling requirements and therefore lower cost than a single shared filter in the prior art. Because there is a separate path for the transmitted signal, the transmit filter also does not need to sacrifice insertion loss (IL) to meet the blocking requirements of the receiver 22. Further, the reduction of the insertion loss IL for the transmission filter will contribute to thermal efficiency and power efficiency. Because there is a separate path for the received signal, the receive filter does not have to sacrifice its insertion loss IL to meet the transmit spurious emission requirements, and the reduction in insertion loss IL for the receive filter is a noise figure. And will contribute to the improvement of reception sensitivity. Changes in the receive filter may be applied by activating or bypassing the third filter according to the power level of the interfering signal. Since the third filter 344 is relieved of power handling (processing) requirements and passive intermodulation requirements, more flexibility may be provided in implementing the third filter 344. If more attenuation is required compared to a conventional TDD filter, the transmit filter will have better power handling performance.

  Although the embodiments have been illustrated and described herein, those skilled in the art can make various changes and modifications and make the above elements equivalent without departing from the true scope of the present technology. It will be appreciated that substitutions may be made. In addition, many modifications may be made to adapt to a particular situation without departing from the central scope of the teachings. Therefore, the present embodiment is not limited to the specific embodiment described as the best mode for performing the present technology, but the present embodiment covers all implementations that fall within the scope of the appended claims. It is excluded to include the form.

Claims (1)

A wireless network entity for improving filtering performance in a time division duplex (TDD) wireless communication system,
A first type of signal to be transmitted to or received from a device in the wireless communication system via a wireless interface using a common filtering requirement satisfied for transmission and reception. A first filter (42) configured to perform filtering;
A second filter configured to perform a second type of filtering for the signal transmitted to the device using the satisfied common filtering requirement and additional filtering requirements for transmission. (43)
A third filter configured to perform a third type of filtering for the signal received from the device using the fulfilled common filtering requirements, and additional filtering requirements for reception (44) and
The frequency attenuation of the second filter is different from the frequency attenuation of the third filter, and the first filter satisfies the basic attenuation for both the transmission path and the reception path, and the second filter A wireless network entity , wherein the third filter satisfies the required attenuation only in the receive path, and satisfies the required attenuation only in the transmit path .

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