ES2648814T3 - System and method to avoid interference of hybrid FDM / TDM coexistence - Google Patents

Abstract

One method, comprising: detecting (1801) in an IDC interference problem of coexistence in the device between the first radio transceiver (1602) and the second radio transceiver (1603) co-located on a device platform (1601) and transmitting (1802) an IDC interference indicator (1621) from the first radio transceiver (1602) to a base station (1611) in a wireless system (30; 1600), characterized in that the method further comprises reporting (1803) information ( 1621) IDC to the base station (1611), where the information (1621) IDC comprises both recommendation for frequency division multiplexing configurations, FDM, and time division multiplexing, TDM, where the recommendation for configuration FDM comprises frequency information indicating an unusable frequency based on LTE measurement results, and where the recommendation for TDM configuration comprises parameters for disk reception ntinua, DRX, operation based on WiFi traffic and programming information.

Description

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DESCRIPTION

System and method to avoid interference of hybrid FDM / TDM coexistence Background of the invention Field of the invention

The disclosed embodiments are generally related to wireless network communications, and, more particularly, to solutions to avoid interference of the device coexistence (IDC).

Description of the related technique

The ubiquity of network access has almost been made today. From the point of view of the network infrastructure, different networks belong to different layers (for example, distribution layers, cellular layer, access point layer, personal network layer, and fixed / wired layer) that provide different levels of coverage and connectivity to users. Since the coverage of a specific network may not be available anywhere, and since different networks can be optimized for different services, it is so! It is desirable that user devices support multiple radio access networks on the same device platform. As the demand for wireless communication continues to increase, wireless communication devices such as cell phones, personal digital assistants (PDAs), smart handheld devices, laptops, tablet computers, etc., are being so Crescent equipped with multiple radio transceivers. A multiple radio terminal (MRT) can simultaneously include a radio with long-term Evolution (LTE) or with advanced LTE (LTE-A), a wireless local area network (WLAN, for example, WiFi), access radio, a Bluetooth radio (BT) and a radio with Global Navigation Satellite System (GNSS).

Due to the scarcity of the radio spectrum resource, different technologies can operate in overlapping or adjacent radio spectra. For example, LTE / LTE-A TDD mode often operates at 2.3-2.4 GHz, WiFi often operates at 2,400-2,483.5 GHz, and BT often operates at 2,402-2,480 GHz. Simultaneous multi-operation. Radios co-located in the same physical device, therefore, may undergo significant degradation that includes significant coexistence interference between them or due to overlapping or adjacent radio spectra. Due to the physical proximity and the escape of radio power, when the transmission of data for a first radio transceiver overlaps with the reception of data for a second radio transceiver in the time domain, the second reception of the radio transceiver can suffer due to interference from the first transmission of the radio transceiver. Similarly, the transmission of data from the second radio transceiver may interfere with the reception of data from the first radio transceiver.

Figure 1 (prior art) is a diagram illustrating the interference between an LTE transceiver, and a co-located WiFi / BT transceiver and the GNSS receiver. In the example in Figure 1, the user equipment (UE) 10 is an MRT comprising a transceiver 11 LTE, a receiver 12 GNSS and a transceiver 13 BT / WiFi placed on the same platform of the device. The LTE transceiver 11 comprises an LTE baseband module and an RF LTE module coupled to a # 1 antenna. The GNSS receiver 12 comprises a GNSS baseband module and an RF GNSS module coupled to antenna # 2. The BT / WiFi 13 transceiver comprises a BT / WiFi baseband module and a BT / WiFi RF module coupled to a # 3 antenna. When the LTE transceiver 11 transmits radio signals, both the 12 GNSS receiver and the BT / WiFi transceiver 13 may suffer from LTE coexistence interference. Similarly, when the BT / WiFi transceiver 13 transmits radio signals, both the GNSS receiver 12 and the LTE transceiver 11 may suffer coexistence interference from the BT / WiFi. As the UE10 can communicate simultaneously with multiple networks through different transceivers and avoid / reduce the coexistence interference this is a challenging problem.

Figure 2 (prior art) is a diagram illustrating the signal strength of the radio signals of two co-located RF transceivers. In the example of Figure 2, transceiver A and transceiver B are co-located on the same platform of the device (ie, in the device). The transmission signal (TX) by transceiver A (for example, WiFi TX in ISM CH1) is very close to the reception signal (RX) (for example, LTE RX in Band 40) for transceiver B in the domain of frequency. The output of the band emission (OOB) is a spurious emission by transceiver A may be unacceptable to transceiver B resulting in an imperfect TX filter and an RF design. For example, the power level of the TX signal by transceiver A may still be greater (for example 60 dB higher before filter) than the power level of signal RX for transceiver B even after filtering (for example, after deletion of 50dB).

In addition to the imperfect TX filter and the RF design, the imperfect RX filter and the RF design can cause coexistence interference in the unacceptable device. For example, some of the RF components may be saturated due to the transmission power from another transceiver in the device, but they cannot be completely filtered, resulting in a saturation of the low noise amplifier (LNA) and causing the analog to digital converter (ADC) work improperly. Such a problem really exists no matter how much separation

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frequency exists between the TX channel and the RX channel. This is because a certain level of TX power (for example, from a harmonic TX signal) can be coupled to the RX RF front end and saturate its LNA. Several solutions for mitigating coexistence interference in the device are sought.

From US 2009/088177 A1, the frequency division multiplexed method, FDM / time division multiplexed, TDM, is known to avoid coexistence interference, which comprises the steps of:

detect a problem of coexistence interference in the device between a first radio transceiver and a second radio transceiver co-located on a platform of the device,

transmit an IDC interference indicator from the first radio transceiver to a base station in a wireless system, and

Report IDC information to the base station, where the IDC information includes both recommendation for FDM and TDM configurations.

From 3GPP “Third Generation Association Project; Radio Access Networks of the Technical Specification Group; Universal Terrestrial Radio Access Evolved (E-UTRA); Study on serialization and procedures to avoid interference for coexistence in the device; (Version 10) ”" in 3GPP DRAFT; R2-106004 TR 36.816 V0.2.0, 3RD GENERATION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTER; 650, ROUTE DES LUCIOLES, F-06921 SOPHIA-ANTIPOLIS CEDEX; FRANCE, vol. RAN WG2, No. Xia an, China; 201010; 19 October 2010 (2010-10-19), XP050491856, It is known a mechanism to avoid interference in LTE and GPS / ISM radios on the same device, which are working on frequencies adjacent or at subharmonic frequencies.

From WO 2009/127690 a method is known to enable multiple wireless communication systems to operate in similar radio spectrum and / or geographically located close to each other.

A wireless device is contemplated that has a central control entity that coordinates the multiple radio transceivers co-located within the same platform of the device to mitigate the coexistence interference. The wireless device comprises the central control entity, an LTE transceiver, a WiFi / BT transceiver, and a GNSS receiver.

In one example, the central control entity receives information from the radio signal of the transceivers and determines the control information. The control information is used to trigger the frequency division multiplexing (FDM) solution such that the transmitted / received signals are moved to the designated frequency channels to mitigate the coexistence interference. The signal information comprises the coexistence interference measurement information, the received signal quality information, the transmission status, an LTE service frequency information, a WiFi frequency channel information, a jump range information of BT frequency, and a center frequency information of the GNSS signal. The control information for the FDM solution comprises an instrument for triggering the LTE transceiver to indicate to an LTE base station that frequency channels are affected by coexistence interference, an instruction to trigger the LTE transceiver to send indication to an LTE base station to switch (for example, cell change, RLF) from a first RF carrier to a second RF carrier, an instruction or recommendation to switch or use a new WiFi channel for the WiFi transceiver, and an instruction to adjust the jump range of frequency for the BT transceiver.

In another example, the central control entity receives traffic information and programming from the transceivers and determines the control information. The control information is used to trigger the time division multiplexing (TDM) solution such that the transceivers are programmed to transmit or receive radio signals for a specific duration time to mitigate the coexistence interference. The traffic and programming information includes the transmission status, the mode of operation, the priority request, the quality of the received signal or the strength, the traffic pattern information, WiFi beacon reception time information, LTE configuration DRX, BT master / slave, and type of GNSS receiver. The control information for the TDM solution comprises an instruction to trigger the LTE transceiver to send the recommendation of the ON / OFF duration, Radio ON / OFF, start time, or duty cycle for the DRX configuration to an LTE base station, an instruction to terminate or resume the TX or RX of the LTE / WiFi / BT Transceiver for a specific duration of time, an instruction for the WiFi transceiver to control the transmission / reception time when negotiating with the WiFi access point (AP) at Use power saving protocol.

In yet another example, the power control solution is used to mitigate coexistence interference. For LTE power control, the central control entity determines a maximum power restriction level for the LTE transceiver, based on the quality of the signal received for the WiFi / BT / GNSS receiver. The maximum power restriction level is that recommended by the LTE transceiver to an LTE base station. For power control

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WiFi / BT, the central control entity instructs the WiFi / BT transceiver to adjust the transmission power level if the quality of the signal received for the signal is poor.

Another example provides a hybrid FDM / TDM solution to prevent interference of coexistence in the device. A user equipment (UE) comprises a first radio transceiver and a second co-located radio transceiver. The UE detects the interference of coexistence between two radios based on the measurement of the signal. The UE sends an IDC interference indicator to its service base station (eNB). The UE also reports IDC information, which includes recommendation for FDM and TDM configurations to the eNB. The eNB receives the IDC interference indicator and evaluates whether to trigger the solution based on FDM to mitigate the coexistence interference. The eNB also evaluates whether to trigger the TDM-based solution to mitigate coexistence interference. The evaluation is based on the recommended FDM and TDM configurations. The eNB can trigger the FDM-based solution, the TDM-based solution or the FDM and TDM solution based on the results of the evaluation of the feasibility and effectiveness of each solution.

US 2009/088177 A1 corresponds to a method according to the preamble of revindication 1. The present invention is defined by the subject matter of the final claims.

Brief description of the drawings

The accompanying drawings, where reference numerals indicate similar components, illustrate embodiments of the invention.

Figure 1 (prior art) is a diagram illustrating the interference between the LTE transceiver and the co-located WiFi / BT transceiver and the GNSS receiver.

Figure 2 (prior art) is a diagram illustrating the power signal of the radio signals of two RF transceivers co-located on the same platform of the device.

Figure 3 illustrates a user equipment that has multiple radio transceivers in a wireless communication system in accordance with a novel aspect.

Figure 4 illustrates a first embodiment of a simplified block diagram of an LTE user equipment having a central control entity.

Figure 5 illustrates a second embodiment of a simplified block diagram of an LTE user equipment having a central control entity.

Figure 6 illustrates a global spectrum allocation around a 2.4 GHz ISM band in more detail.

Figure 7 illustrates a first example of an FDM solution to avoid coexistence interference in the 3GPP device.

Figure 8 illustrates a second example of an FDM solution to avoid coexistence interference in the 3GPP device.

Figure 9 illustrates an example of a TDM solution to avoid coexistence interference in the 3GPP device.

Figure 10 illustrates a first example of a power control solution to avoid coexistence interference in the 3GPP device.

Figure 11 illustrates a second example of a power control solution to avoid coexistence interference in the 3GPP device.

Figure 12 illustrates a detailed procedure of avoiding coexistence interference in the device using a central control entity in accordance with a novel aspect.

Figure 13 is a flow chart of a method to avoid coexistence interference using FDM solution.

Figure 14 is a flow chart of a method to avoid coexistence interference using the TDM solution.

Figure 15 illustrates the measurement results in WiFi and LTE coexistence interference and the corresponding noise generation with different filters.

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Figure 16 is a simplified block diagram of a user terminal and a base station in a wireless communication system according to a novel aspect.

Figure 17 illustrates the exchange of communication and message between the UE and the eNB for solutions in order to avoid FDM / TDM coexistence interference.

Figure 18 is a flow chart of a hybrid FDM / TDM solution method to avoid IDC interference from the EU perspective.

Figure 19 is a flow chart of a hybrid FDM / TDM solution method to avoid IDC interference from the eNB perspective.

Detailed description of the invention

Reference will now be made in detail to some embodiments of the invention, the examples of which are illustrated in the accompanying drawings.

Figure 3 illustrates a user equipment UE 31 that has multiple radio transceivers in a wireless communication system 30 in accordance with a novel aspect. The wireless communication system 30 comprises a user equipment UE31, a service base station (for example, an evolved node B) eNB32, an AP33 WiFi WiFi access point, a BT34 Bluetooth device and a satellite device with global positioning system GPS35. The wireless communication system 30 provides several network access services for the UE31 via different radio access technologies. For example, the eNB32 provides access to the cellular radio network (for example, a long-term 3GPP (LTE) or Advanced LTE (LTE-A) evolution system), the AP33 WiFi provides local coverage in network access Wireless LAN (WLAN), the BT34 provides short-range personal network communication, and the GPS35 provides global access as part of a Global Navigation Satellite System (GNSS). To better facilitate the various radio access technologies, the UE31 is a multiple radio terminal (MRT) that is equipped with multiple radios co-located on the same platform of the device (that is, on the device).

Due to the scarce radio spectrum resources, different radio access technologies can operate in overlapping or with adjacent radio spectra. As illustrated in Figure 3, the UE31 communicates the radio signal 36 with eNB32, the radio signal 37 with the WiFi AP33, the radio signal 38 with the BT34, and receives the radio signal 39 of the GPS35. The radio signal 36 belongs to the Band 40 3GPP, the radio signal 37 belongs to one of the WiFi channels, and the radio signal 38 belongs to one of the seventy-nine Bluetooth channels. The frequencies of all those radio signals fall within a range of 2.3GHz to 2.5GHz, which can result in significant coexistence interference with one another. In a novel aspect, the UE31 comprises a central control entity that coordinates with different radio transceivers within the same device platform to mitigate coexistence interference.

Figure 4 illustrates a first embodiment of a simplified block diagram of a wireless communication device 41 having a central control entity. The wireless communication device 41 comprises memory 42, a processor 43 having a central control entity 44, a LTE / LTE-A transceiver 45, a GPS receiver 46, a WiFi transceiver 47, a Bluetooth transceiver 48 and a bus 49 In the example of Figure 4, the central control entity 44 is a logical entity physically executed within the processor 43, which is also used to process the application of the device for the device 41. The central control entity 44 is connected to several transceivers within the device 41, and communicates with several transceivers via bus 49. For example, the WiFi transceiver 47 transmits the WiFi signal information and / or the WiFi traffic and the programming information to the central control entity 44 (for example, represented by a thick dotted line 101). Based on the WiFi information received, the central control entity 44 determines the control information and transmits the control information to the LTE / LTE-A transceiver (for example, represented by a thick dotted line 102). In one embodiment, the LTE transceiver 45 communicates additionally with its service base eNB40 station based on the control information received to mitigate the coexistence interference (for example, represented by thick dotted line 103).

Figure 5 illustrates a second embodiment of a simplified block diagram of a wireless device 51 having a central control entity. The wireless communication device 51 comprises memory 52, a processor 53, a transceiver 54 LTE / LTE-A having a central control entity 55, a GPS receiver 56, a WiFi transceiver 57, a Bluetooth transceiver 58 and a bus 59 Each transceiver contains a local control entity (for example, the MAC processor), a radio frequency (RF) module and a baseband (BB) module. In the example of Figure 5, the central control entity 55 is a logical entity physically executed within a processor that is physically located within the transceiver 54 LTE / LTE-A. Alternatively, the central control entity 55 may be physically located within the WiFi transceiver or within the Bluetooth transceiver. The central control entity 55 is coupled to several radio transceivers co-located within the device 41 and which is

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communicates with several local control entities via bus 49. For example, the WiFi control entity within the WiFi transceiver 57 transmits WiFi information to the central control entity 55 (for example, represented by the thick dotted line 104). Based on the WiFi information received, the central control entity 55 determines the control information and transmits the control information to the LTE control entity within the transceiver 54 LTE / LTE-A (for example, represented by a dotted line 105 gross.). In one embodiment, transceiver 54 LTE / LTE-A further communicates with the service base station based on control information received to mitigate coexistence interference (for example, represented by a thick dotted line 106).

How to effectively mitigate coexistence interference is a challenging problem for co-located radio transceivers operating in overlapping or adjacent frequency channels. The problem is more severe around the 2.4 GHz ISM radio frequency band (Industrial, Scientific and Medical). Figure 6 illustrates a global spectrum allocation around a 2.4 GHz ISM band in more detail and the corresponding impact of coexistence interference from WiFi to LTE in the 3GPP Band 40. As illustrated in the upper table 61 of Figure 6, the 2.4 GHz ISM band (for example, ranging from 2400-2483.5MHz) is used for both fourteen WiFi channels and seventy-nine Bluetooth channels. The use of WiFi channels depends on the WiFi AP decision, while Bluetooth uses frequency hopping through the ISM band. In addition to the agglomerated ISM band, the 3GPP Band 40 ranges from 2300-2400MHz, and the 7 UL Band ranges from 2500-2570MHz, both are very close to the 2.4GHz ISM radio frequency band.

Table 62 below in Figure 6 illustrates the impact of coexistence interference from WiFi to LTE in the 3GPP Band 40 under a typical attenuation filter. Table 62 lists the desensitization value of an LTE transceiver that operates on a specific frequency channel (for example, each row of Table 62) that is interfered with by a relocated WiFi transceiver that operates on another specific frequency channel (for example , Each column of Table 62). The desensitization value in Table 62 indicates that both the sensitivity of the LTE receiving serial needs to be reinforced in order to achieve the same serial quality (eg SNR / SINR) as if there was no interference from the co-located WiFi transceiver. For example, if the LTE transceiver operates at 2310MHz and the WiFi transceiver operates at 2412MHz, then the LTE receives signals that need to be reinforced to 2.5 dB to offset any coexistence interference. On the other hand, if the LTE transceiver operates at 2390MHz and the WiFi transceiver operates at 2412MHz, then the LTE reception signal needs to be reinforced to 66dB to offset any coexistence interference. Therefore, without the mechanism to avoid further interference, the traditional filter solution is insufficient to mitigate coexistence interference in such a way that different radio access technologies can work well independently on the same platform of the device.

Different solutions have been sought to avoid coexistence interference. Among the different solutions to avoid interference, frequency division multiplexing (FDM), time division multiplexing (TDM), and power management are three of the main solutions proposed in accordance with the present invention. Additionally, a central control entity is used to coordinate the co-located transceivers and to facilitate the various solutions to avoid interference. Detailed embodiments and examples of various solutions to avoid interference are now described below with the accompanying drawings.

Figure 7 illustrates a first example of an FDM solution to avoid 3GPP coexistence interference. In the example of Figure 7, an LTE transceiver is co-located with a WiFi / BT transceiver. The transmission signal (TX) by the WiFi / BT transceiver (for example, signal 71 WiFi / BT TX) is very close to the reception signal (RX) for the transceiver lTe (for example, signal 72 RX LTE) in The frequency domain. As a result, out-of-band (OOB) emission and spurious emission of the WiFi / BT transceiver is unacceptable to the LTE transceiver resulting in imperfect TX filter and an RF design. (For example, the power level of the WiFi / BT TX signal may still be higher (for example, 60 dB higher before filtering) than the power level of the LTE RX signal even after filtering (for example, after 50dB suppression) without the mechanism to avoid further interference As illustrated in Figure 7, a possible FDM solution is to move the 72 LTE RX signal away from the ISM band when using the cell change procedure.

In LTE systems, most of the activities that include cell change procedures are controlled by the network. Therefore, at the start of the EU-assisted FDM solutions controlled by the LTE network, the UE can send an indication to the network to report the problem that results from coexistence interference, or to recommend that a certain action be taken (for example, cell change). For example, when there is an ongoing interference in the service frequency, the indication can be sent to the UE as long as it has a problem in the LTE downlink (DL) or in the ISM DL reception that cannot resolve itself, and the eNB has not yet taken action based on the RRM Measurements. Indication triggers, based on the criteria predefined or configured by the eNB, may also be based on whether there is unacceptable interference in the service frequency, or if there is an ongoing or potential interference on other frequencies that are not in service .

The ability to coordinate the device is required to support the 3GPP FDM solution. From the LTE perspective, the LTE transceiver first requires knowing (for example, via an internal controller) if another transceiver or transceivers in the device are transmitting or receiving within the same limited time latency. More specifically, the LTE transceiver requires to know the length of time when the LTE transceiver can measure the

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coexistence interference due to WiFi / BT transmission, the length of time when the LTE can receive without coexistence interference from the WiFi / BT transceivers, based on that knowledge, and the LTE transceiver can measure the coexistence interference and evaluate which frequencies may or may not be seriously interfered (for example, unusable frequencies) for the LTE RX. The LTE transceiver will then indicate the unusable frequencies to the eNB to trigger FDM. From the WiFi / BT / GNSS perspective, the LTE transceiver also requires knowing whether the LTE transmission in which the frequencies will result in an unacceptable performance to other receivers in the WiFi / BT / GNSS device. Once the LTE transceiver determines that the significant coexistence interference is triggered by the FDM solution, the UE sends an indication to the eNB to request a cell change from the current service frequency to another frequency that is remote from the WiFiBT / GNSS signal.

Figure 8 illustrates a second example of an FDM solution to avoid 3GPP coexistence interference. Similar to Figure 7, out-of-band (OOB) emission and spurious emission by the WiFi / BT transceiver is unacceptable for the LTE transceiver to result in an imperfect TX filter and RF design. As illustrated in Figure 8, the FDM solution is to move the ISM signal (for example, signal 81 WiFi / BT TX) away from the received signal LTE (for example, signal 82 LTE RX). In one example, the WiFi transceiver can receive an instruction to switch to a new WiFi channel remote from the LTE band, or a recommendation on which WiFi channel can be used. In another example, the Bluetooth transceiver can receive an instruction to adjust its frequency hopping range.

Figure 9 illustrates an example of a TDM solution to avoid 3GPP coexistence interference. The basic principle of the TDM solution is to reduce the time overlap between the WiFi / BT TX and the LTE RX to avoid coexistence interference. In a DRM-based TDM solution, a UE recommends the DRX configuration parameters to its service eNB. Similar to the FDM solution, the device's coordination capability is required to support the TDM solution based on 3GPP DRX. For example, a control entity is used to derive the recommended ON / OFF DRX configuration for the eNB. The control entity receives information from co-located WiFi / BT transceivers that include the type of operation (for example, WiFi AP, BT master), traffic states (for example, Tx or Rx) and characteristics (for example, activity level , traffic pattern) and priority demand, and determines the recommended ON / OFF DRX duration, the ON / OFF DRX ratio, the duty cycle, and the start time.

In a TDM solution based on HARQ reservation, a UE recommends a bitmap or some assistance information to help its eNB perform a submarine level programming control to avoid interference. Several methods for programming the transmission and reception time slots for co-located radio transceivers have been proposed. For example, a BT device (for example, RF # 1) first synchronizes its communication time slots with the co-located cellular radio module (for example, RF # 2), and then obtains the traffic pattern (for example, BT eSCO) of the co-located cellular radio module. Based on the traffic pattern, the BT device selectively slides one or more TX or RX time slots to prevent the transmission or reception of data in certain time slots and thereby reduce interference with the co-located cellular radio module. The skipped time slots are disabled for TX or RX operation to avoid interference and achieve more power savings. For additional details on multi-radio coexistence, see: US Patent Application Series Number 12/925, 475, entitled "System and Methods for Enhancing Coexistence efficiency for multi-radio terminals," filed on 22, 2010, by Ko et al.

In addition to DRM and HARQ-based TDM solutions, the autonomous denial of the UE is another type of TDM solution to avoid interference. In one embodiment, the LTE transceiver stops the UL TX to protect the ISM or GNSS DL RX. This may happen infrequently and for short-term events, otherwise the LTE connection performance may be impacted. In another embodiment, on the WiFi or BT transceiver stops the UL TX to protect the LTE DL Rx. This may be necessary to protect an important LTE DL signal, such as the radio messaging. The UE autonomous negation solution also requires the ability to coordinate the device (for example, via an internal controller). The LTE transceiver requires knowing the priority RX request from the BT / GNSS WiFi receiver and when the LTE UL TX terminates. The LTE transceiver also needs to be able to indicate its own RX priority request to the internal controller to terminate the WiFi / BT UL TX. In addition, such knowledge needs to be indicated in a real-time manner or be indicated in a specific pattern.

Figure 10 illustrates a first example of a power control solution to avoid 3GPP coexistence interference. As illustrated in Figure 10, when the WiFi / BT signal 107 occurs in a frequency channel close to that of the 108 LTE RX signal, the ISM transmission power of the WiFi / BT transceiver is reduced. For example, based on the signal quality received from LTE, an internal controller can send an instruction to the WiFi / BT transceiver to adjust the transmission power level.

Figure 11 illustrates a second example of a power control solution to avoid 3GPP coexistence interference. Similar to Figure 10, when the 111 LTE TX signal occurs on a frequency channel close to the 112 WiFi / BT RX signal, the transmission power of the LTE transceiver can be reduced. In LTE systems, however, the legacy LTE power control mechanism may not be broken by coexistence. Therefore, instead of reducing the power of LTE TX directly, a more acceptable solution is to adjust the power height range. For example, based on the quality of the received WiFi / BT / GNSS signal, an internal controller evaluates a new

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maximum transmission power restriction level. The new level of maximum transmission power restriction is then recommended by the LT transceiver to its eNB.

Since the ability to coordinate the device is required to support several solutions to avoid coexistence interference, this is proposed as well! such that the central control entity is implemented in a wireless device to coordinate the co-located radio transceivers. Referring again to Figure 4 or Figure 5, the central control entity (for example, 44 in Figure 4 or 55 in Figure 5) communicates with all radio transceivers in the co-located device and makes decisions for Avoid coexistence interference. The central control entity detects which transceivers are connected and then enables the corresponding coexistence interference coordination. If a specific transceiver / receiver is not connected to the central control entity, it is assumed as uncoordinated where the central control entity can instruct other transceivers to effect avoiding passive interference (for example, BT to reduce the jump range).

Figure 12 illustrates a detailed procedure to avoid coexistence interference using a central control entity in the device in a wireless communication system. The wireless communication system comprises a UE containing a central control entity and several co-located radio transceivers that include the LTE, WiFi, BT transceivers and a GNSS receiver. In order to facilitate various solutions to avoid interference, the central control entity first requires collecting information from the co-located transceivers and thus determining and sending control information to coordinate the co-located transceivers (phase 121). For example, the central control entity receives signal / traffic / programming information from a first transceiver (for example, LTE, in step 151) and sends the corresponding control information to a second transceiver (for example, WiFi / BT / GNSS, in step 152). Similarly, the central control entity receives signal / traffic / programming information from the second transceiver (for example, WiFi / BT / GNSS, in step 153) and sends the corresponding control information to the first transceiver (for example, LTE , in step 154). The transceivers then perform certain actions based on the control information received to trigger the FDM / TDM power control solution.

Under the FDM solution (phase 122), the central control entity receives information from the radio signal and determines the control information to trigger the FDM solution. The radio signal information related to the FDM solution may include the following: transmission status (for example, ON or OFF, TX mode or RX mode), coexistence interference level, quality or strength of the received signal (by example, RSRP level, RSRQ, LTE CQI), LTE service frequency, WiFi frequency channel information, BT frequency hopping range information, and GNSS signal center frequency. Based on the radio signal information, the central control entity determines whether the measured coexistence interference should trigger the FDM solution (for example, in step 161 for LTE and step 162 for WiFi / BT / GNSS) . If the FDM solution has to be triggered, then the central control entity sends the following control information: an instruction to trigger the LTE transceiver to indicate to the eNB LTE the downlink reception problem due to coexistence interference, an instruction to trigger the LTE transceiver to send which frequencies may or may not be seriously interfered due to coexistence (for example, usable or unusable frequencies) to the eNB LTE, an instruction to trigger the LTE transceiver to send an indication to the eNB LTE for operation cell change (for example, step 163), an instruction to the WiFi transceiver to switch to a new WiFi channel, a recommendation to the WiFi transceiver to use a specific WiFi channel, and an instruction to the BT transceiver to adjust the jump range of BT frequency (for example, step 164).

In LTE systems, in order to mitigate coexistence interference effectively, the LTE transceiver requires knowing when to measure coexistence interference and when to report the coexistence problem to the eNB. An important role of the central control entity is to collect information on whether the WiFi / BT transceiver is transmitting or receiving within a limited time latency. The control entity will then determine the duration of time where the LTE receiver can measure the coexistence interference, and the length of time where the LTE receiver can receive without coexistence interference. The trigger condition to report coexistence problems and to apply the FDM solution is configured by the network. Additionally, it should be noted that the final decision of the FDM solutions, such as the frequency of service after cell change, although triggered based on the control information, is also made by the eNB (not the UE) in the LTE systems.

Under the TDM solution (phase 123), the central control entity receives traffic and programming information and determines the control information to trigger the TDM solution. Traffic and programming information related to the TDM solution may include the following: transmission status (for example, ON or OFF, TX mode or RX mode), level of coexistence interference, quality or strength of the received signal (for example , RSRP, RSRQ, CQI level of the LTE), TX or RX priority request (for example, important TX or RX signal), operation mode (for example, WiFi AP mode, WiFi STA mode, BT eSCO, BT A2DP, acquisition of initial satellite signal, GNSS tracking mode), WiFi beacon reception time information, LTE DRX configuration, LTE connection mode (for example, RrC_CONNECTED or RRC_IDLE), LTE Duplex mode (for example, TDD or FDD), configuration of carrier aggregation LTE (CA), master or slave BT, traffic pattern information (for example, BT periodicity, TX / RX slot number required) and type of GNSS receiver (for example, GPS, GLONASS, Galileo, Beidou or dural receptor).

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Based on the traffic and programming information, the central control entity sends the instruction to the local control entity in an LTE transceiver to trigger the TDM along with part of the following control information: ON / OFF duration or proportion of Work cycle information for the LTE transceiver to recommend the DRX configuration to the LTE eNB (for example, step 171), an adequate starting time to trigger and avoid LTE interference, an adequate starting time to trigger and avoid LTE interference , a time in which the LTE transceiver must terminate the signal transmission (for example, step 172), an instruction to terminate the LTE UL transmission within a certain time latency, an instruction to terminate the WiFi / BT transmission during a specific time duration (for example, step 173), a specific time duration information when the WiFi / BT / GNSS can receive signal without interference from LTE coexistence, an instruction to terminate the WiFi / BT transmission within a certain latency of time, an instruction to resume the WiFi / BT transmission, or an instruction to negotiate with the WiFi WiFi AP remote over the data transmission and / or the reception time by the power saving protocol (for example, step 174), an instruction to switch the coexistence pattern BT TX / RX ON / OFF, and the specific time duration information at which the GNSS signal reception LTE coexistence interference may occur.

Under the power control solution (phase 124), the central control entity receives the radio signal and the power information and determines the control information to trigger the power control solution. The radio signal and the power information for the power control solution mainly include the quality of the received signal measured by the LTE / WiFi / BT / GNSS, the transmission power information of the WiFi / BT and the power level of maximum current transmission of the LTE. For LTE power control, the central control entity can rely on the quality of the received WiFi / BT / GNSS signal to estimate how much additional interference it could suffer. The central control entity may also rely on the maximum current LTE transmission power level to estimate the maximum LTE transmission power level that can be achieved by WiFi / BT / GNSS to achieve the minimum received signal quality (stage 181). On the other hand, for WiFi / BT power control, the central control entity can simply instruct the WiFi / BT transceiver to adjust the transmission power level if the quality of the received signal for the LTE signal is poor (step 182 ).

It should be noted that the information listed for FDM, TDM and power control solutions are exemplary and not mutually exclusive. Instead, additional information can be applied to any other solution, and the same information can be applied in multiple solutions. For example, information on the type of operation or traffic pattern information, although mainly used for the TDM solution, can also be used for the FDM solution to determine whether to trigger a possible cell change procedure. Additionally, different solutions can be applied together with a better mitigation of coexistence interference.

It should also be noted that although the purpose of the solutions illustrated above is to avoid and reduce coexistence interference, coexistence interference cannot always be avoided or reduced after applying the various FDM / TDM / Power control solutions. For example, in some geographic area, the LTE network is only deployed on a poor frequency and an LTE device will always be changed from cell to frequency with worse coexistence interference once it moves to that geographical area.

Figure 13 is a flow chart of a method to avoid coexistence interference using the FDM solution. The wireless device comprises multiple radio transceivers and a central control entity. The central control entity receives a first radio signal information from a first control entity that belongs to a first LTE transceiver (step 131). The central control entity also receives a second radio signal information from a second control entity belonging to a second radio transceiver co-located with the first transceiver (step 132) LTE. Based on the first and second radio signal information, the central control entity determines the control information, and transmits the control information to the first and second entities (step 133) of control. At least in part based on the control information, the first and second transceivers operate on the designated frequency channels and thus mitigate the coexistence interference.

Figure 14 is a flow chart of a method to avoid coexistence interference using the TDM solution. A wireless device comprises multiple radio transceivers and a central control entity. The central control entity receives a first traffic and programming information from a first control entity that belongs to the first LTE transceiver (step 141). The central control entity also receives a second traffic information and information from the second control entity belonging to the second radio transceiver co-located with the first LTE transceiver (step 142). Based on the first and second traffic and programming information, the central control entity determines the control information, and transmits the control information to the first and second control entities (step 143). At least in part, based on the control information, the first and second transceivers are programmed to transmit and receive radio signals of a specific duration of time and thus mitigate the coexistence interference.

FDM / TDM Hybrid Solution

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The actual level of coexistence interference from one radio transceiver to another co-located radio transceiver can be measured in real radio devices. Figure 15 illustrates the results of WiFi coexistence interference measurements to LTE and the corresponding noise generation with different filters. T res WiFi modes are used for measurement. The first mode is 802.11b WiFi with a data rate of 1M and 23dBm of Pout. The second mode is 802.11g WiFi with a data rate of 54M and 20dBm of Pout, and the third mode is WiFi 802.1 with a data rate of 65M and 18dBm of Pout. As illustrated in Table 1501, the transmission power density on a # 1 WiFi channel (2412MHz) is - 47.68dBm / Hz, -51.5dBm / Hz, and -54dBm / Hz, respectively for radio signals of the three WiFi modes. The receive power density in the 40 LTE Band (2370MHz) is -107.6dBm / Hz, - 107.SdBm / Hz, and -110.7dBm / Hz, respectively, for the radio signals of the three WiFi modes.

By using an additional bandpass filter (BPF) and antenna isolation, it is possible to achieve some additional performance improvement. Different WiFi BFP and antenna isolation entail different performance improvements for the TD-LTE in the 40 band. In the ideal case, the achievable BFP performance for WiFi is 45dB, and the antenna isolation can achieve 20dB. In a normal case, the achievable BFP performance for WiFi is 40dB, and the antenna isolation can achieve 15dB. In the worst case, the achievable WiFi BFP performance is 35dB, and the antenna isolation can achieve 10dB.

As illustrated in Table 1502, in an ideal case, the noise generation due to WiFi coexistence interference is 1.4 dB for 802.11b, 1.5 dB for 802.11g and -1.7dB for 802.1 and In. In a normal case, noise generation due to WiFi coexistence interference is 11.4dB for 802.11b, 11.5dB for 802.11g and 8.3dB for 802.1 In. In the worst case, in a specific example, the reduction of the path loss available for the control channel is 16.79dB for 802.11b, 16.89dB for 802.11g and 13.78dB for 802.11n, and the reduction of the coverage of the Control channel due to coexistence interference is 1.4km ^ 0.5km (87% coverage loss) for 802.11b, 1.4km ^ 0.5km (87% coverage loss) for 802.11b, and 1.4km ^ 0.6 km (81% coverage loss) for 802.1 In. Therefore, the filter seems unable to completely solve the WiFi coexistence problem. Although the ideal filter and antenna isolation can lead to acceptable performance, the normal (or worse) filter and antenna isolation will result in an unacceptable performance. In addition, it is risky to link the performance of the TD-LTE with the specific filter and only rely on the solution of the filter. Very few filter vendors can supply the aforementioned ideal filter, and antenna isolation is hard to be guaranteed.

Although the FDM-based solution seems promising, the presumption about the feasibility and effectiveness of the FDM solution is based on the significant reduction of IDC interference when the frequency separation between the service frequency and the target frequency is increased. However, this may not be true because the level of reduction may not be sufficient to mitigate IDC interference to an acceptable level. Additionally, the problem of WiFi coexistence interference exists throughout the band 40 for the TD-LTE. In fact, there is only a difference of 2.6dB between 2320MHz and 2370MHz based on the measurement results. Therefore, the FDM-based solution may not always work, and the coexistence interference may remain high, even by moving the LTE signals away from the ISM band.

In a novel aspect, a wireless network applies a solution based on hybrid FDM / TDM to mitigate the problem of coexistence interference. First, the network assesses whether the FDM solution is feasible and sufficient to solve the problem of coexistence interference. If so, then the network instructs the cell change UE at another frequency away from the ISM band. If not, then the network tries to activate the TDM solution. In addition, after activating the FDM solution, the network evaluates whether the problem of coexistence interference has been sufficiently resolved. If not, then the network tries to activate the TDM solution.

Figure 16 is a simplified block diagram of a user equipment UE 1601 and an eNB base station 1611 in a wireless communication system 1600 in accordance with a novel aspect. The UE 1601 comprises a 1602 LTE / LTE-A transceiver, a co-located 1603 WiFi transceiver and an IDC interference detection module 1604. Similarly, eNB 1611 comprises memory 1612, a processor 1613, a transceiver 1614 LTE / LTE-A and an IDC interference control module 1615. In a novel aspect, the UE 1601 detects IDC interference between the LTE and the WiFi radios, and transmits an IDC interference indicator 1621 to the eNB 1611. The UE 1601 also transmits additional IDC information that includes the recommended FDM and TDM configurations to the eNB1611. For example, the recommended FDM configuration is an unusable frequency based on the LTE measurement results, and the recommended TDM configuration conforms to the DRX parameters based on the WiFi traffic / programming information. Based on the IDC interference indicator received and the IDC information, eNB 1611 assesses the feasibility and effectiveness of any MDF-based and / or TDM-based solution to mitigate IDC interference. After evaluation, eNB 1611 sends messages / configurations 1622 to UE 1601 for the determined FDM / TDM solution.

Figure 17 illustrates a communication and message exchange process between UE 1701 and eNB 1702 to apply solutions to avoid hybrid FDM / TDM coexistence interference. In step 1710, the UE 1701 first makes a measurement of the radio signal of the service cell. The UE 1701 also measures the radio signal of the neighboring cells at frequencies different from the frequency of the service cell. EU 1701 drift

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IDC measurement results agree with this. The IDC measurement results may include a received signal strength indicator (RSSI) (reference signal received power (RSRP)), a signal to interference and noise ratio (SINR) (reference signal received quality (RSRQ) ), channel quality indicator (CQI) proportion of block error (BLER), or performance results. In step 1720, the UE 1701 detects if there is an IDC interference problem between the co-located radio modules based on the IDC measurement results. Detection can be done by comparing the level of interference received (or the level of total received power) with or without the transmission of coexistence interference source. Note that the results of the IDC measurement may not be the same compared to the traditional RSRP / RSRQ definition. Instead, the results of the IDC measurement are derived based on the traffic / time information of the co-located radios. For additional details in determining the results of the IDC measurement and detecting the IDC interference problem, please see: US Series Patent Application Number 13 / 136,862 entitled "Method to Trigger In-device Coexistence Interference Mitigation in Mobile Cellular Systems ", presented on August 11, 2011, by I-Kang Fu et al. (whose subject matter is incorporated here as a reference)

Once UE 1701 detects an IDC interference problem, UE 1701 indicates the problem of coexistence interference by sending an IDC interference indicator to eNB 1702 (step 1730). Note that the interference indicator itself only indicates the problem (for example, neutral), without triggering any specific solution, or providing any specific recommendation on which the solution is applied. However, UE 1701 may send additional IDC information that accompanies the indicator to help eNB 1702 assess which solution is most applicable. The IDC information may include the recommendation of the FDM and TDM configuration based on the measurement results obtained in step 1710, and the traffic and programming information of a co-located radio module (for example, obtained from a central control entity ).

After the eNB 1702 receives the IDC interference indicator, it begins to evaluate possible FDM-based solutions to mitigate the interference (step 1740). First, eNB 1702 evaluates whether any FDM solution is feasible. For example, eNB 1702 evaluates whether the change from cell UE 1701 to another cell located at different frequencies than the frequency of the original service cell is feasible. Then, eNB 1702 evaluates whether the problem of coexistence interference can be effectively solved by changing cell UE1701 to another frequency. The evaluation can be done by comparing the RSSI (RSRP) or SINR (RSRQ) measurement results on the original service cell and neighboring cells at different frequencies. In a first example, if the measurement result in a target cell is lower than that of the service cell, this implies that the effectiveness of the FDM solution may also be lower. In a second example, if the result of the RSSI measurement (RSRP) in another cell on different frequency is greater than that in the original cell, then the eNB can expect the FDM solution to be sufficient. In a third example, if the SINR measurement (RSRQ) results in another cell on different frequency is much higher than that of the original cell, then the eNB can expect the FDM solution to be sufficient.

If eNB 1702 finds a cell suitable for UE 1701 for cell change based on the evaluation, then eNB 1702 triggers the FDM solution upon initiating a cell change procedure (step 1750). On the other hand, the eNB 1702 may not trigger any FDM solution based on the evaluation. For example, eNB 1702 may not find any suitable cell for cell change. In another example, if the cell load associated with the target frequency is greater than a certain threshold, then eNB 1702 may not trigger the FDM solution. In another example, if the evaluation results in showing that the coexistence interference cannot be resolved sufficiently by way of cell change at another frequency, the eNB 1702 may not trigger the FDM solution.

In step 1760, eNB 1702 additionally evaluates possible TDM-based solutions to mitigate coexistence interference (step 1760). The evaluation can be based on the co-located ISM traffic and the programming information sent from the UE 1701 together with the interference indicator. For example, if the ISM traffic has a certain periodicity, then eNB 1702 can configure UE 1701 with the corresponding DRX configuration to reduce interference (step 1770). Note that step 1760 is carried out regardless of whether the FDM solution has already been applied or not. Even if the UE 1701 has already changed cells at another frequency, the eNB 1702 continues to assess whether the problem of coexistence interference has been sufficiently resolved and if the TDM solution needs to be further activated. Additionally, it should be noted that the order of steps 1740 and 1760 is interchangeable. That is, the eNB 1702 can first evaluate and apply the TDM based solution and first evaluate and apply the FDM based solution.

Figure 18 is a flow chart of a hybrid FDM / TDM solution method to avoid IDC interference from the EU perspective. In step 1801, the UE detects the problem of coexistence interference between the first radio transceiver and the second co-located radio transceiver. In step 1802, the UE transmits an IDC interference indicator to a base station. In step 1803, the UE also reports IDC information to the base station. The IDC information includes recommendations for the FDM and TDM configurations based on the measurement result and the traffic / programming information of the second radio transceiver.

Figure 19 is a flow chart of a hybrid FDM / TDM solution method to avoid IDC interference from the eNB perspective. In step 1901, an eNB receives an IDC interference indicator from the UE in a wireless system. In step 1902, the eNB also receives IDC information from the UE. The IDC information includes recommendations for the FDM and TDM configurations based on the measurement result and the traffic / programming information. In step 1903, the eNB determines whether to trigger the FDM solution to mitigate the IDC interference problem. In step 1904, the eNB determines whether firing the TDM solution mitigates the IDC interference problem.

Although the present invention has been described in connection with certain specific embodiments for instructional purposes, the present invention is not limited to this. For example, although an advanced LTE mobile communication system 10 is exemplified to describe the present invention, the present invention can similarly apply to other mobile communication systems, such as the multiple-access systems by division of synchronous code by time division ( TD-SCDMA). Accordingly, various modifications, adaptations and combinations of various features of the described embodiments can be practiced without departing from the scope of the invention as set forth in the claims.

Claims (18)

5 10 fifteen twenty 25 30 35 40 1. A method, comprising: detecting (1801) in an IDC interference problem of coexistence in the device between the first radio transceiver (1602) and the second radio transceiver (1603) co-located on a device platform (1601) and transmit (1802) an IDC interference indicator (1621) from the first radio transceiver (1602) to a base station (1611) in a system (30; 1600 wireless), characterized in that the method also includes report (1803) information (1621) IDC to the base station (1611), where the information (1621) IDC includes both recommendation for frequency division multiplexing configurations, FDM, and time division multiplexing, TDM, wherein the recommendation for the FDM configuration comprises frequency information indicating an unusable frequency based on LTE measurement results, and where the recommendation for TDM configuration includes parameters for discontinuous reception, DRX, operation based on WiFi traffic and programming information. 2. The method of claim 1, further comprising: determine the recommendation for the FDM configurations by measuring a reference signal quality and determine the recommendation for the TDM configurations based on the traffic and programming information of the second radio transceiver (1603). 3. The method of claim 2, wherein the recommendation for FDM configurations is determined based on a quality received from the RSRQ reference signal, from a service cell; or wherein the recommendation for the FDM configuration is determined based on the quality received from the reference signal, RSRQ, of a neighboring cell at a frequency different from the service frequency. 4. The method of claim 2, wherein the IDC interference problem is detected based on the measurement result. 5. A method, comprising: receiving (1901) a coexistence interference indicator (1621) in the IDC device, from a user equipment (1601) by means of a base station (1611) in a wireless system (1600), characterized in that the method further comprises: receiving (1902) information (1621) IDC of the user equipment (1601), where the information (1621) IDC includes both recommendation for configurations of multiplexing by frequency division FDM, as multiplexing by time division, TDM; determine (1903) whether to fire an FDM solution to mitigate IDC interference based on IDC information, wherein the recommendation for the FDM configuration comprises frequency information indicating a frequency not usable based on the LTE measurement results; Y determine (1904) whether to fire a TDM solution to mitigate IDC interference based on IDC information, where the recommendation for TDM configuration includes parameters for discontinuous reception, DRX, operation based on WiFi traffic information and programming. 6. The method of claim 5, wherein the FDM solution involves switching from cell to user equipment (1601) from a service cell to a target cell located on a different frequency based on the recommendation for FDM configurations. 5 10 fifteen twenty 25 30 35 40 7. The method of claim 6, wherein the recommendation for FDM configurations is determined based on the quality received from the reference signal, RSRQ, of the service cell; or wherein the recommendation for FDM configurations is determined based on the quality received from the reference signal, RSRQ, of the target cell at the different frequency 8. The method of claim 5, wherein the TDM solution involves programming the user equipment (1601) to transmit and receive radio signals for a specific duration of time based on the traffic and programming information. 9. The method of claim 5, wherein the station (1611) triggers the FDM solution if the base station (1611) determines that the FDM solution is applicable if there is a significant reduction in IDC interference. 10. The method of claim 5, wherein the base station (1611) further determines whether to fire the TDM solution after firing the FDM solution. 11. The method of claim 5, wherein the base station (1611) triggers both the FDM solution and the TDM solution. 12. A base station (1611), comprising: a receiver (1614) adapted to receive a coexistence in the device, IDC, the interference indicator (1621) from a user equipment (1601) in a wireless system (1600), characterized because the receiver (1614) is also adapted to receive IDC information (1621) from the user equipment (1601) wherein the information (1621) IDC includes both a recommendation for FDM frequency division multiplexing configurations, and time division multiplexing, TDM; Y wherein the recommendation for the FDM configuration comprises frequency information indicating a frequency not usable based on the LTE measurement results, and where the recommendation for the TDM configuration includes parameters for the discontinuous reception, DRX, operation based on the WiFi traffic and the programming information; Y an IDC control module (1615) adapted to determine whether to trigger an FDM solution to mitigate IDC interference based on the IDC information, wherein the control module (1615) is also adapted to determine whether to trigger a TDM solution to mitigate IDC interference based on the IDC information 13. The base station (1611) of claim 12, wherein for the FDM solution, the IDC control module (1615) is also adapted to change the user equipment (1601) from a service cell to a cell of service to a target cell located on a different frequency based on the recommendation for FDM configurations. 14. The station (1611) base of claim 13, wherein the recommendation for FDM configurations is determined based on the reference signal in the quality received from the reference signal, RSRQ of the service cell; or wherein the recommendation for the FDM configuration is determined based on the quality received from the reference signal, RSRQ, of the target cell at the different frequency. 15. The base station (1611) of claim 12, wherein, for the TDM solution, the IDC control module (1615) is further adapted to program the user equipment (1601) to transmit and receive radio signals during a specific duration of time based on traffic information and programming. 16. The base station (1611) of claim 12, wherein the base station (1611) is adapted to trigger the FDM solution if the base station (1611) determines that the FDM solution is applicable if there is a significant reduction in interference IDC 17. The base station (1611) of claim 12, wherein the base station (1611) is further adapted to determine whether to fire the TDM solution after firing the FDM solution. 18. The base station (1611) of claim 12, wherein the base station (1611) is adapted to trigger both the FDM solution and the TDM solution.