KR101931194B1 - Lte/wi­fi coexistence - Google Patents

Abstract

The method of communication at the wireless device 24 includes establishing a first connection with a base station (BS 28) of a long haul wireless data network and a second connection over a Wireless Local Area Network (WLAN). The time interval 96 is selected in the wireless device communicating via the second connection. With the selected time interval provisioning, the BS prevents the scheduling of data transmission from the wireless device to the BS over the first connection for a time interval by reporting to the BS before the time interval that there is no pending data for transmission from the wireless device . The wireless device communicates over the second connection on the WLAN during the time interval.

Description

LTE WIFI Coexistence {LTE / WIFI COEXISTENCE}

The present invention relates to wireless communication, particularly coexistence between wireless communication devices.

In some communication systems, communication devices of different communication protocols operate in a frequency band that is close to and adjacent to or overlapping with each other. Because of proximity in location and frequency, such systems may tend to be interfered.

Various techniques for coexistence between different communication protocols are known in the art. For example, U.S. Patent Application Publication 2007/0275746, incorporated herein by reference, establishes a first communication session over a first connection between a base station (BS) and a wireless terminal of a long haul wireless data network, It operates according to a first protocol that defines a sequential time frame. Based on the time frame defined by the BS, the time slot is allocated to establish a second communication session via a second connection between the wireless terminal and the peripheral wireless device, which is different from the first protocol by a second short- And operates in accordance with the slotted communication protocol. The time interval is allocated within a time frame for communication between the BS and the wireless terminal over the first connection so that the assigned time interval is interleaved with and overlapped with the assigned time slot. The first and second communication sessions are performed simultaneously in the assigned time interval and the assigned time slot, respectively.

U.S. Patent Application Publication No. 2009/0129367, the disclosure of which is incorporated herein by reference, includes assigning a time interval for a first communication session over a first connection between a wireless terminal and a station of a long distance wireless data network, Lt; RTI ID = 0.0 > downlink < / RTI > and uplink subframes. A time slot is allocated for a second communication session over a second connection between the terminal and the peripheral wireless device, which is different from the first protocol and operates according to a second short-range time-slotted protocol with a retransmission mechanism do. The time slot is synchronized with the downlink and uplink sub-frames defined by the BS. The operation of the second connection is prohibited during a portion of the time slot that overlaps the downlink sub-frame to cause the terminal to invoke a retransmission mechanism and cause the terminal to transmit only during a time slot that does not overlap the downlink sub-frame .

U.S. Patent No. 7,542,728, the disclosure of which is incorporated herein by reference, discloses a method and apparatus for transmitting and receiving first and second downconverted signals, respectively, over different first and second wireless networks in accordance with different first and second network protocols, And at least one RF receiver circuit coupled to receive and down-convert the first and second RF signals. The baseband processing circuit includes a processing component coupled to receive and process the first and second downconverted signals to extract first and second data from the signal. The processing component has a first configuration for demodulating a first downconverted signal according to a first network protocol and a second configuration for demodulating a second downconverted signal according to a second network protocol.

U.S. Patent No. 7,545,787 and U.S. Patent Application Publication No. 2010/0142504, the disclosures of which are incorporated herein by reference, define a sequential time frame for data transmission between a wireless terminal and a station between a wireless terminal and a station in a long haul wireless data network And establishing a first connection operating in accordance with the first protocol. A signal is transmitted from the wireless terminal to the station identifying a time interval that includes one or more time frames while the wireless terminal is not receiving data from the station. During a time interval, the second connection is established between the wireless terminal and an access point of a wireless local area network (WLAN) according to a second protocol different from the first protocol.

Some communication devices communicate simultaneously over long distance data networks (e.g., Long Term Evolution-LTE networks) and Wireless Local Area Networks (WLAN). In fact, transmissions on one network can interfere with reception on other networks, especially when the transceivers are combined and the two networks overlap or operate in adjacent frequency bands.

The embodiments of the invention described in the text provide improved methods and systems for coexistence that help to reduce or eliminate such interference. Although the embodiments described herein primarily refer to LTE and WLAN (also referred to as Wi-Fi), the disclosed technique is similarly applicable to other appropriate network types.

The embodiments of the invention described in the text provide a method of communication in a wireless device. The method includes establishing a first connection with a base station (BS) of a long haul wireless data network and a second connection over a wireless local area network (WLAN). The time interval is selected in the wireless device communicating via the second connection. In preparation for the selected time interval, the BS may schedule data transmission from the wireless device to the BS over the first connection for a time interval by reporting to the BS before the time interval that there is no pending data for transmission from the wireless device . The wireless device communicates over the second connection on the WLAN during the time interval.

In some embodiments, reporting that there is no pending data is performed even when some data is pending for transmission to the BS to schedule the transmission of pending data out of time intervals by the BS. In an embodiment, the method includes reporting that there is pending data for transmission from a wireless device in preparation for the end of a time interval. Reporting that there is pending data may include reporting the amount of data that is different from the actual size of the pending data to control the size of the scheduled transmission.

In another embodiment, the long haul wireless data network operates in accordance with the Long Term Evolution (LTE) specification, and reporting that there is no pending data includes transmitting a buffer status report (BSR) message. In another embodiment, the method comprises applying alternating communication patterns between the first and second connections by alternately reporting to the BS that there is pending data and that there is no pending data. In yet another embodiment, the method includes suppressing communication over a second connection prior to and following the selected time interval. Reporting to the BS may include sending a report message to the BS at a time that takes into account the scheduling latency of the first connection.

In accordance with one embodiment of the present invention, there is further provided a wireless device comprising a radio frequency (RF) front end and a baseband circuit. The RF front end is configured to exchange RF signals for communication over a long distance wireless data network and a Wireless Local Area Network (WLAN). The baseband circuit establishes a first connection with the BS of the long haul wireless data network and a second connection over the WLAN via the RF front end, selects a time interval communicating over the second connection, Thereby preventing scheduling of data transmissions from the wireless device to the BS over the first connection during the time interval by reporting to the BS before the time interval that there is no pending data for transmission from the wireless device, Lt; RTI ID = 0.0 > connection. ≪ / RTI >

A method is provided for communication in a wireless device in accordance with an embodiment of the present invention. The method includes establishing a first connection with a base station (BS) of a long haul wireless data network with an interleaved sequence of uplink intervals for transmission to the BS and downlink intervals for reception from the BS. At the same time as the first connection, the second connection is established in the wireless station and the stations of the Wireless Local Area Network (WLAN) arranged very close to the wireless device. Interference from transmission on the station in the second connection to reception of the BS in the first connection is prevented by sending a signal from the wireless device to the station to block the station from transmitting during the downlink time interval.

In some embodiments, preventing interference includes blocking the wireless device from transmitting to the station on the second connection to prevent the station from transmitting an acknowledgment message to the wireless device during the downlink time interval . In one embodiment, preventing interference includes transmitting a CTS-to-Self message to the station. In the disclosed embodiment, preventing interference includes scheduling transmissions from the wireless device to the station such that each acknowledgment message from the station occurs during the uplink time interval of the first connection. Scheduling the transmission includes setting each parameter of the transmission such that acknowledgment occurs during the uplink time interval. The parameters may include the duration and / or the start time of the transmission.

In yet another embodiment, preventing interference includes communicating with the station using a Modulation and Coding Scheme (MCS) selected such that the transmission of the station is fitted out of the downlink time interval. The method may include transmitting to the station using a selected MCS (modulation and coding scheme) to account for interference from transmission of the wireless device over the first connection to reception of the station over the second connection.

In one embodiment, the method further comprises transmitting an acknowledgment message to the station at a power level lower than the normal power level used for data transmission to the station, and transmitting an acknowledgment message to the MSC . In another embodiment, preventing interference includes transmitting the signal to a power level selected to inhibit blocking of the station but not blocking other stations that are not proximate to the wireless device. In yet another embodiment, preventing interference includes synchronizing the time base of the second connection to the frame time base of the first connection at a wireless device.

In accordance with one embodiment of the present invention, there is further provided a wireless device comprising a radio frequency (RF) front end and a baseband circuit. The RF front end is configured to exchange RF signals to communicate over a long distance wireless data network and over a Wireless Local Area Network (WLAN). The baseband circuit builds a first connection with the BS (base station) of the long distance wireless data network in the intervening sequence of the uplink time interval for transmission to the BS and the downlink time interval for reception from the BS via the RF front end Establishing a second connection with a station of a WLAN located very close to the wireless device, and sending a signal from the wireless device to the station to block the station from transmitting for the downlink time interval And to prevent interference from transmission of the station on the second connection to reception of the BS on the first connection.

There is also provided a method for communication in a wireless device in accordance with an embodiment of the present invention. The method includes the steps of: establishing a first connection with a base station (BS) of a long haul wireless data network and a second connection over a Wireless Local Area Network (WLAN) simultaneously with the first connection, Lt; RTI ID = 0.0 > a < / RTI > first connection in a predefined mode. Wherein transmission over the second connection is configured based on a pattern of predefined active and inactive periods for the first connection to reduce interference between the first connection and the second connection.

In some embodiments, the first connection operates in accordance with the Long Term Evolution (LTE) specification, which includes Semi-Persistent Scheduling (SPS) and / or Discontinuous Reception (DRX). In one embodiment, configuring the transmission includes preventing transmission over the second connection from occurring during an active period of the first connection. In yet another embodiment, configuring the transmission includes controlling transmission of the wireless device over the second connection.

In the disclosed embodiment, configuring the transmission includes controlling transmission of the opposite endpoint with which the wireless device communicates through the second connection. In another embodiment, the step of configuring the transmission is based on the identification of the active time allocated for the uplink transmission and the active time allocated for the downlink transmission, the power level to be used for the transmission, and / And controlling the transmission. The step of configuring the transmission includes synchronizing the time base of the second connection with the frame time base of the first connection at the wireless device.

Additionally, in accordance with one embodiment of the present invention, there is further provided a wireless device comprising a radio frequency (RF) front end and a baseband circuit. The RF front end is configured to exchange RF signals to communicate over a long distance wireless data network and over a Wireless Local Area Network (WLAN). The baseband circuit is configured to establish a first connection with a base station (BS) of a long-haul wireless data network and a second connection on the WLAN simultaneously with the first connection through an RF front end and to predefine a pattern of active and inactive periods Mode and a second connection based on a pattern of predefined active and inactive periods for the first connection to reduce interference between the first connection and the second connection, And is configured to configure transmission over a connection.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood by considering the following detailed description of the embodiments thereof and the drawings.

1 is a block diagram that schematically illustrates an LTE / Wi-Fi communication system in accordance with one embodiment of the present invention;
2 is a flow chart schematically illustrating a method for LTE / Wi-Fi coexistence according to one embodiment of the present invention;
Figures 3 and 4 are diagrams illustrating the timing of LTE and Wi-Fi transmissions according to embodiments of the present invention;
5 is a block diagram that schematically illustrates an LTE / Wi-Fi communication system in accordance with another embodiment of the present invention;
Figure 6 is a diagram illustrating the timing of LTE and Wi-Fi transmissions according to one embodiment of the present invention; And
7 is a flowchart schematically illustrating a method for LTE / Wi-Fi coexistence according to another embodiment of the present invention.

(survey)

Some communication devices communicate simultaneously over long distance data networks (e.g., Long Term Evolution-LTE networks) and Wireless Local Area Networks (WLAN). In fact, transmissions on one network can interfere with reception on other networks, especially when the transceivers are combined and the two networks overlap or operate in adjacent frequency bands.

The embodiments of the invention described in the text provide improved methods and systems for coexistence that help to reduce or eliminate such interference. Although the embodiments described herein primarily refer to LTE and WLAN (also referred to as Wi-Fi), the disclosed technique is similarly applicable to other appropriate network types.

In some disclosed embodiments, a wireless device communicates with a LTE base station (BS) simultaneously with a WLAN station (STA) or an access point (AP). In accordance with the LTE specification, the BS schedules uplink transmissions from the wireless device in response to a buffer status report (BSR) message in which the wireless device reports the amount of pending data for transmission. The wireless device utilizes the BSR mechanism to create a time interval without LTE uplink transmission and thus can be used for Wi-Fi communication without interference.

In some embodiments, the wireless device selects a time interval to be used for Wi-Fi communication. In preparation for the selected time interval, the wireless device frees the time interval in the LTE uplink transmission by sending a BSR of zero to the BS, i. E. Reporting to the BS that there is no pending data. Upon receipt of the BSR = 0 message, the BS does not schedule any uplink data transmissions from the wireless device until it receives a non-zero BSR. Thus, the wireless device uses the time interval following the BSR = 0 message for Wi-Fi communication without risk of LTE interference.

In another disclosed embodiment, the wireless device communicates with the LTE BS in a time division (TD) LTE mode with an interleaved sequence of uplink and downlink time intervals. At the same time, the wireless device communicates with a Wi-Fi STA located adjacent to the wireless device. Due to the proximity, out-of-band emissions from the STA's Wi-Fi transmitter in the LTE band can interfere with LTE reception. In some embodiments, the wireless device prevents this interference by sending a signal to the local STA to prevent the STA from transmitting during the downlink time interval.

In another disclosed embodiment, the wireless device is configured by the LTE BS to communicate in an interspersed pattern of active periods (e. G., LTE sub-frames) separated by an inactive period. For example, a wireless device may be configured to operate in a semi-persistent scheduling (SPS) mode and / or a discontinuous reception (DRX) mode, both of which are defined in the LTE specification. In some embodiments, the wireless device coordinates communications on the WLAN based on the LTE activation / deactivation pattern to reduce interference.

(System description)

1 is a block diagram that schematically illustrates an LTE / Wi-Fi communication system 20 in accordance with one embodiment of the present invention. The system 20 includes a communication device 24 that communicates simultaneously over both a long distance data network and a Wireless Local Area Network (WLAN).

In this example, the long distance data network operates according to the 3GPP Long Term Evolution (LTE) specification. In December 2010, LTE, also known as Evolved Universal Terrestrial Radio Access (E-UTRA), is described, for example, in "Technical Specification Group Radio Access Network (E-UTRA) 3GPP Technical Specification TS 36.300, entitled " Evolved Universal Terrestrial Radio Access Network (E-UTRAN), Overall description: Stage 2 (Release 9) In the context of the present patent application and claims, the term "LTE specification" collectively refers to any standard or standard that defines an LTE communication, including variations and extensions to the cited standard. In alternate embodiments, the long-haul data network may operate in accordance with other appropriate current or future specifications or protocols.

The WLAN in this example operates in accordance with the IEEE 802.11 standard. For example, WLAN operation in the 2.4 GHz frequency range is described in " IEEE Standard for Information Technology < RTI ID = 0.0 > : Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, "IEEE standard 802.11-2007. WLAN is also known as Wi-Fi. In the context of the present patent application and claims, the terms "WLAN" and "Wi-Fi" refer to the original IEEE 802.11 standard and all variations and extensions thereof -2009) collectively.

In the embodiment of FIG. 1, the device 24 communicates with an LTE base station (BS) 28, also referred to as an eNodeB. Thus, the device 24 functions as an LTE user equipment (UE). On a Wi-Fi network, in some embodiments, the device 24 functions as a Wi-Fi base station (STA), and in other embodiments, as a Wi-Fi access point (AP). Thus, the device 24 communicates with the Wi-Fi STA or AP 32 via the WLAN. The device 24 may be implemented in, for example, a multimode communication device such as a smart phone, a portable router, a static router, or any other suitable device.

In various embodiments, LTE and Wi-Fi communications are performed in adjacent frequency bands. In one exemplary embodiment, the device 24 is configured to transmit the uplink (UL) in the 2500-2570 MHz range and the downlink (DL) in the 2620-2690 MHz range and in the 2400-2480 MHz range on the Wi-Fi network And operates in accordance with LTE frequency division duplex (FDD) in band 7. Alternatively, other operating modes (e. G., Time division duplex-TDD) and frequency bands may also be used. Because of the proximity of location and frequency, operation in one network may experience interference from other networks. As described in more detail below, device 24 applies coexistence to reduce or eliminate such interference. When using this technique, the device 24 can perform LTE and Wi-Fi communication sessions concurrently with little or no performance degradation on any one network.

Although the embodiments described herein primarily refer to a single communication device with both LTE and Wi-Fi capabilities, some of the disclosed techniques are similarly applicable to separate but short-lived LTE and Wi-Fi devices that suffer interference have.

In the embodiment of Figure 1 the device 24 comprises an antenna 36 and a radio frequency (RF) front end 40 by means of which the device 24 can communicate with the RF < RTI ID = 0.0 > And exchanges signals with the BS 28 and the AP or STA 32. The LTE baseband (BB) processor 44 performs the LTE UE processing function of the apparatus. The Wi-Fi BB processor 48 performs the Wi-Fi (STA or AP) processing function of the device.

In some embodiments, LTE and Wi-Fi BB processors communicate with each other through a coexistence interface to exchange information to assist in LTE / Wi-Fi coexistence. The front end 40 is shared between LTE and Wi-Fi, i.e., performs transmission and reception for both LTE and Wi-Fi networks. The RF front end may include appropriate filters to mitigate or reduce some of the LTE / Wi-Fi interference.

The configuration of the device 24 shown in FIG. 1 is an exemplary configuration, which has been selected for purely conceptual clarity. In alternative embodiments, any other suitable device configuration may be used. For example, LTE and Wi-Fi communications can be performed over separate RF front-ends and antennas. As another example, the functions of the BB processors 44 and 48 may be performed by a single BB processor. In the present context, the BB processors 44 and 48 are referred to as baseband circuits that perform collectively disclosed techniques. Certain elements of device 24 may be implemented using hardware, such as using one or more application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). Alternatively, some of the elements of device 24 may be implemented in software or using a combination of hardware and software elements.

In some embodiments, the functionality of the device 24 may be implemented using a general purpose computer programmed with software to perform the functions described herein. The software may be downloaded to the computer in electronic form, for example over a network, or alternatively or additionally, provided and / or stored on non-tangible media, such as magnetic, optical or electronic memory .

(Coexistence using buffer status report (BSR))

In some embodiments, the device 24 generates a free time interval in the LTE uplink transmission (from the device to the BS 28) by utilizing a buffer status report (BSR) message defined in LTE. These time intervals can then be used for Wi-Fi communication without the risk of LTE transmissions from device 24 affecting Wi-Fi reception at the device.

The BSR mechanism is described in detail in the " Technical Specification Group Radio Access Network (E-UTRA); Medium Access Control (MAC) protocol " (Release 9), "version 9.3.0, 3GPP TS 36.300 section 11.3, and 3GPP TS 36.321 section 5.4.5. According to this definition, the LTE UE uses a BSR message buffered in its own transmission buffer and reporting the amount of pending data for transmission to the BS. A BSR of 0 indicates that there is no pending data. The LTE BS schedules the uplink transmissions of the various UEs based on the BSR messages they have transmitted. In particular, if a particular US reports BSR = 0, the BS does not schedule uplink data transmissions for this UE until it receives a subsequent non-zero BSR.

In some embodiments, the BB processor 44 in the device 24 selects a time interval for communicating over the Wi-Fi network. With the selected time interval provisioning, the BB processor 44 sends a BSR = 0 message (indicating that there is no pending data for transmission to the BS) to the BS 28 prior to the time interval so that the time interval is free in the LTE uplink transmission It is guaranteed to be robust. The BB processor 44 sends a non-zero BSR message (indicating that a certain amount of data is waiting) towards the end of the time interval. In response to receiving the BSR = 0 message, the BS 28 will inhibit scheduling of LTE uplink transmissions from the device 24. The BS will schedule the LTE uplink transmission after receiving a non-zero BSR message.

In this manner, the BB processor 44 may cause the system 20 to alternate between the intended time interval for LTE uplink transmissions and the time interval free (and thus usable for Wi-Fi communication) for LTE uplink transmissions It is possible to operate in a pattern that occurs.

2 is a flow chart schematically illustrating a method for LTE / Wi-Fi coexistence according to an embodiment of the present invention. This method begins by the BB processor 44 sending a BSR message to the BS 28 reporting a non-zero BSR in a non-zero BSR step 60. [

In some embodiments, device 24 blocks Wi-Fi communication during the time interval that will be used for LTE uplink transmissions in Wi-Fi blocking step 64. For example, the BB processor 44 may cause the BB processor 48 to inhibit Wi-Fi communication by sending an appropriate indication via the coexistence interface.

Upon receipt of a non-zero BSR, the BS 28 schedules uplink transmissions from the device 24. With this assignment, the BB processor 44 sends the pending data to the BS 28 for an uncertain time interval in the LTE uplink transmission step 68.

At the end of the LTE uplink interval, the BB processor 44 reports a BSR of zero, i. E., A message to the BS 28 in BSR step 72 of 0 that there is no pending data in the transmit buffer. In response to the BSR message of 0, the BS 28 suppresses scheduling of LTE uplink transmissions from the device 24. [ Thus, the BB processor 48 communicates with the STA or AP 32 over the Wi-Fi network in the Wi-Fi communication phase 76 without the risk of interference from LTE uplink transmissions.

The method then loops back to step 60 to schedule another LTE uplink interval. Using this technique, the device 24 enforces a pattern that occurs alternately in the LTE uplink interval and the free interval in the LTE uplink transmission.

Using this method, in at least some scenarios, the device 24 may report a BSR of zero even though some data is pending in its transmission buffer. This type of reporting allows the BS to schedule the transmission of this data on the LTE uplink only after receiving a subsequent non-zero BSR. That is, this technique may cause device 24 to defer transmission of uplink data until the end of the time interval.

Generally, there is a certain waiting time between the transmission of a non-zero BSR message from the device 24 and the scheduling of the uplink transmission by the BS 28. [ This latency is generated by the LTE protocol, and its size is on the order of 10ms. Generally, the BB processor 44 takes this latency into account when setting the timing of the time interval. In some embodiments, the BB processor 44 sets the size and / or duty cycle of the time interval while taking into account the actual throughput for the LTE connection from the device 24 to the BS 28. This parameter may be set, for example, by setting the reported BSR value (the reported amount of panning data).

For example, consider an average uplink throughput of 10 Mbps (= 10 Kbit / ms) and assume that the desired active time (length of each LTE uplink interval) is 10 ms. In this case, transmitting a BSR message reporting that the pending data is 100 kb will cause the BS to schedule uplink transmissions of approximately 10 ms. Thus, at least in some cases, the amount of data that the device 24 reports in a non-zero BSR message is different from the actual amount of pending data for transmission.

3 is a diagram showing timings of LTE and Wi-Fi transmissions according to an embodiment of the present invention. The example of FIG. 3 illustrates how the device 24 generates a time interval for the LTE uplink and a free time interval in the LTE uplink transmission using the BSR mechanism described above.

The top of Figure 3 shows the LTE control messaging, and in particular the non-zero BSR message 80 sent from the device 24 to the BS 28 and the BSR message 88 at zero. The middle part of FIG. 3 shows the timing of LTE uplink data transmission. BS 28 schedules LTE uplink transmissions 84 at a constant waiting time (e.g., 10 ms) subsequent to each non-zero BSR 80. [ The bottom of Figure 3 shows the time period of Wi-Fi activation. In particular, Wi-Fi activation is blocked during the interrupted interval 92 (corresponding to LTE uplink transmission 84) to prevent interference from LTE uplink transmissions.

The device 24 sends a BSR message 88 of zero towards the end of the LTE uplink transmission to the BS 28. [ Following the BSR message of 0, the BS does not schedule LTE uplink transmissions until the next non-zero BSR message 88. [ Thus, this BSR message forms a Wi-Fi activation period 96 in which the device 24 can communicate on the Wi-Fi network without interference from the LTE uplink.

In one exemplary embodiment, each uplink data transmission 84 is 20 ms long and each Wi-Fi active period 96 is 15 ms long. Alternatively, however, any other suitable length may be used.

The LTE BB processor 44 may block Wi-Fi communications during time intervals 92 in various manners. In one embodiment, the LTE BB processor 44 clearly communicates the timing of the time interval 92 to the Wi-Fi BB processor 48 using a coexistence interface between the BB processors. The Wi-Fi BB processor may be configured in any suitable manner, for example by setting a Not-Available (NAV) interval using a process known as "CTS-to-Self" terminating at the end of the time interval 84 Wi-Fi communication may be inhibited during the time interval 92.

In an alternate embodiment (e.g., when the LTE and Wi-Fi BB processors are on separate devices and / or are not connected by a coexistence interface), the LTE BB processor 44 may communicate with the Wi- The timing of the time interval 92 is not given. In these embodiments, Wi-Fi downlink reception during interval 92 may experience interference from LTE uplink transmissions. The level of interference may include, for example, the filtering quality at the RF front end, the separation between LTE and Wi-Fi antennas at device 24, the transmit power and other RF parameters of the LTE transmitter, the RF parameters of the Wi- -Fi May vary with modem quality. In case of heavy interference, the Wi-Fi packet may drop and be retransmitted (either in interval 92 or in a subsequent interference-free interval 84) until packets are successfully received.

BSR-based coexistence techniques may be implemented in device 24 in a variety of ways. In some embodiments, the BSR coexistence scheme is performed by the LTE BB processor 44. This implementation may benefit because the LTE BB processor running the LTE protocol stack already has the necessary information regarding the state of the transmit buffer. In addition, the LTE BB processor may include useful information regarding BS behavior, such as BS latency in response to non-zero BSRs. This kind of information can be used to optimize the coexistence scheme.

In an alternative embodiment, the BSR-based coexistence approach is implemented in another processor external to the LTE BB processor 44. [ In one example, the coexistence scheme may be implemented as a Wi-Fi BB processor 48 in the case of a Wi-Fi AP. In this embodiment, control of the BSR is indirect by another processor that controls the rate of information provided to the LTE BB processor 44. [ Typically in such implementations, such throughput should be implicitly estimated by other processors having to receive clear information on average LTE uplink throughput or by examining outgoing packets. This may be advantageous, for example, because it does not require modification of existing LTE BB processors or other LTE UE elements.

Regardless of the implementation, the size of the LTE transmission buffer in the device 24 must be large enough to hold the uplink packet to support a time duration in which the LTE uplink is inactive.

The above-described BSR-based scheme assumes that the main source of interference in device 24 is from the LTE uplink transmission to the Wi-Fi downlink transmission to reception. The interference in the opposite direction, that is, the reception of the LTE downlink transmission from the Wi-Fi uplink, can be tolerated or mitigated in other ways (e.g., using sufficient filtering in the RF front end 40) .

In some embodiments, following a BSR message of zero, the BS 28 does not schedule data transmission on the LTE uplink, but may schedule a control-related uplink transmission. These control-associated transmissions tend to cause less interference to the Wi-Fi downlink because their output power is generally less than the power of the data transmission. In some embodiments, depending on the level of interference of the predicted level, it is sometimes possible to prevent the transmission of the control-associated transmission.

(BSR-based coexistence for TD LTE US combined with WI-FI access point)

4 is a diagram illustrating the timing of LTE and Wi-Fi transmissions according to one embodiment of the present invention. In this embodiment, the LTE communication of the LTE BB processor 44 is according to the LTE time division (TD), and the Wi-Fi BB processor 48 functions as a Wi-Fi AP. In this example, although any other suitable frame size may also be used, each LTE TD downlink frame and each LTE TD uplink frame is 2.5 ms long.

During the Wi-Fi blocking interval 92, the BB processor 48 prevents Wi-Fi communication as described above. During these intervals (corresponding to interval 84), LTE communications may be performed in both the uplink and downlink directions.

Interference does not occur for Wi-Fi reception by the LTE uplink transmission 108 due to the above-described BSR-based mechanism between intervals 92 (i.e. during the Wi-Fi activation period). However, interference may occur during the LTE downlink transmission 112. (In the FDD scenario, it is assumed that FDD band 7 is used.) In this band, the downlink frequency is relatively large with the Wi-Fi frequency And front-end separation is assumed to be sufficient to prevent interference at interval 96)

In this embodiment, since the Wi-Fi AP is combined with the LTE UE, this interference can be reduced. In some embodiments, a Wi-Fi AP (in this example BB processor 48) is aware of and synchronized to the TD LTE frame timing. The Wi-Fi AP transmission 100 is synchronized with respect to the LTE uplink interval 108. For this purpose, the Wi-Fi AP (BB processor 48) is generally aware of the start time and duration of the LTE uplink interval 108, and to fit (e.g., by fragmenting) Change the Wi-Fi data size.

Additionally, in some embodiments, the termination of each Wi-Fi AP transmission 100 is aligned with the end of the LTE uplink interval 108. This sorting ensures that each Wi-Fi acknowledgment (ACK) 104 (transmitted from the Wi-Fi STA 32 to the Wi-Fi AP at the device 24) is received during the LTE downlink interval 112 do.

A Wi-Fi receiver at device 24 may be allowed to operate during the LTE downlink interval 112. [ When the Wi-Fi burst 116 is received, the Wi-Fi AP at the device 24 must transmit an ACK burst 120. [ The transmitted ACK burst may interfere with the reception of the LTE downlink. In some embodiments, the Wi-Fi AP (BB processor 48) at the device 24 may send an ACK 120 at a lower output power and a lower (more robust) Modulation and Coding Scheme (MCS) Overcome these problems.

Additionally or alternatively, the LTE BB processor 44 may mitigate the interference caused by the ACK 120 as part of LTE downlink reception. This mitigation is possible, for example, because the ACK waveform and associated parameters are known to the device 24 and the duration of the ACK 120 is relatively short. The LTE receiver in this embodiment is informed prior to the parameters of the ACK waveform and cancels this known interference in its demodulation / decoding process.

In an alternate embodiment, the LTE TD frame pattern includes a fixed gap between the uplink interval 108 and the downlink interval 112. These gaps may be used to transmit a Wi-Fi ACK message from the Wi-Fi AP in the device 24 without causing interference.

(Coexistence between combined TD-LTE UE and Wi-Fi APs, and near Wi-Fi stations)

5 is a block diagram that schematically illustrates an LTE / Wi-Fi communication system 130 in accordance with another embodiment of the present invention. In the system 130, the communication device 134 communicates with the LTE BS (eNodeB) 138 using TD LTE and one or more Wi-Fi STAs using Wi-Fi simultaneously. In this example, the device 134 communicates with the remote STA 142 and the local STA 146.

The device 134 may be implemented in, for example, a portable router or smart phone with LTE and Wi-Fi AP functionality. Although the embodiments described herein refer to LTE and Wi-Fi, the disclosed technique is similarly applicable to other long haul data networks or WLANs as described above for FIG.

Apparatus 134 includes an antenna 35 and an RF front end 40 similar to the apparatus 24 of FIG. The device 134 includes an LTE BB processor 150 serving as a TD-LTE UE and a Wi-Fi BB processor 154 serving as a Wi-Fi AP. In some embodiments, the BB processors 150 and 154 communicate with each other via a coexistence interface.

In this embodiment, the STA 146 is placed close to the device 134, such as at a distance of less than 1 m, for example. In the present context, the term "proximity " refers to the distance that the LTE receiver at device 134 experiences interference from the Wi-Fi transmitter of STA 146, even though there is no frequency overlap between them. For example, the STA 146 may transmit noise to out-of-band pseudo signals or bands in the LTE band, and may cause interference in proximity.

STA 146 includes, for example, a netbook, a smartphone, a tablet computer, a laptop computer, or any other suitable type of Wi-Fi station. Because of the proximity of the STA 146 to the device 134, interference may occur to Wi-Fi and LTE reception at the device 134 as well as to Wi-Fi reception at the near Wi-Fi STA 146 have. The following discussion provides exemplary coexistence schemes that mitigate such interference.

The disclosed technique may be used between the combined TD-LTE UE and the Wi-Fi AP between the BB processors 150 and 154 (i.e., at the device 134) to reduce interference to and from the near Wi- ) On the protocol-level cooperation. The inherent assumption is that the STA 146 is designed to be essential for coexistence, such as for example receiver linearity and transmitter emissions. The combined TD-LTE UE and Wi-Fi AP at device 134 are assumed to co-exist, for example, with sufficient filtering at the RF front end 40. This filtering overcomes the interference from LTE transmission of the BB processor 150 to Wi-Fi reception of the BB processor 154 and from Wi-Fi transmission of the BB processor 154 to LTE reception of the BB processor 150 .

In this configuration, interference of a number of different modes may occur as summarized in the following table:

As can be seen in the above table, the main form of interference is from the Wi-Fi transmission of the STA 146 to the LTE reception at the device 134.

Since the distance between the STA 146 and the Wi-Fi AP in the device 134 is small, the STA 146 transmits on the Wi-Fi channel with a high modulation and coding scheme (MCS) Is relatively short. In some embodiments, this feature allows the Wi-Fi bursts transmitted by the STA 146 to fit within (relatively short) LTE UL and DL intervals (typically orders of 2.5 ms).

6 is a diagram illustrating the timing of LTE and Wi-Fi transmissions according to one embodiment of the present invention. The figure illustrates an exemplary coexistence scheme that uses device 134 to reduce interference from Wi-Fi transmission of near-field STA 146 to LTE reception of BB processor 150.

6 shows the frame pattern of the TD-LTE UE (BB processor 150), the middle of the figure shows the operation of the Wi-Fi AP (BB processor 154) at the device 134, The bottom of the figure shows the operation of the local Wi-Fi STA 146.

BB processor 150 operates in a crossing pattern of DL interval 160 and UL interval 164. A UL guard interval 168 is inserted between each DL interval 160 and a subsequent UL interval 164. In an embodiment, the DL interval 160 and the UL interval 164 are of the same size, i.e., between the UL and DL times are 50% / 50%. Each DL and UL interval in this embodiment is an order of 2.2 ms, and the guard interval 168 is an order of 0.6 ms. Alternatively, any other suitable value may be used.

In some embodiments, the combined Wi-Fi AP (BB processor 154) synchronizes the Wi-Fi time base to the LTE frame time base of the BB processor 150. BB processor 154 schedules its Wi-Fi operation based on LTE framing as described below. During the DL interval 160 the BB processor 154 is able to communicate with the STA 146 at least until the start of the next UL guard interval 168 to prevent interference from the STA 146 to the LTE reception of the BB processor 150. [ (E. G., Using a CTS-to-self message or any other suitable technique) to block the traffic of the STA 146. < RTI ID =

The blockage interval 172 at which the STA 146 is blocked is shown in the middle of the figure. As can be seen, the STA 146 does not transmit during the LTE DL time interval 160, i.e. during LTE reception at the BB processor 150. Thus, the case of major interference in system 130 is eliminated.

Because of this blockage, in most scenarios, the STA 146 will start its transmission burst 192 during the UL guard interval because it has been blocked to this point. The transmission burst 192 ends before and after the start of the LTE UL interval 164 below. In either case, the burst 192 will be successfully received by the AP (BB processor 154). The reception of the burst 192 is shown as interval 176 in the figure.

In most cases, the burst 192 will end before the current UL interval 164 due to the assumption of a high MCS possible by the proximity between the STA 146 and the device 134. As described above, since STA 146 is very close to device 134, communication between STA 146 and device 134 shortens the communication burst and allows them to communicate with LTE downlink time interval 160, And can be performed using a high MCS that allows fitting to the outside.

Upon receipt of the burst 192, the BB processor 154 must immediately respond to the ACK 180. The ACK may be transmitted using a low bit rate because the STA 146 may be slightly interfered or insensitive by the LTE UL transmission at interval 164. Receipt of ACK 176 at SAT 146 is shown as interval 196. [ In general, the STA 146 will not initiate the transmission of a new burst for the same LTE UL interval 164 because its CCA mechanism may be blocked as a result of the LTE transmission. The CCA blocking period is shown as interval 200.

In some embodiments, the device 134 (the Wi-Fi AP at the BB processor 154 is shown as a predicted ACK from the STA 146 (marked as interval 208 and received at the AP as interval 188) The LTE UL interval 164 or the subsequent LTE DL interval 160 as long as the transmission is scheduled to be received to be received during the LTE UL interval 164 (current UL interval 164 or subsequent interval 164) Lt; RTI ID = 0.0 > 184 < / RTI >

In some embodiments, the AP (BB processor 154) may determine that the STA 146 has received a high MCS with high interference from the LTE UL transmission (of the BB processor 150) The MCS of the transmission 184 may be reduced to account for the case where it can not be handled.

In some embodiments, the AP (BB processor 154) may extend the duration of a given transmission 184 beyond the LTE DL interval 160 so that the ACK 208 is received during the LTE UL interval 164. The AP may concatenate multiple packets to form a single long transmission 184, for example by deliberately reducing the MCS used for transmission, by adding dummy information bytes to the transmission, or by using any other suitable technique The duration of the transmission 184 can be extended.

In some embodiments, towards the end of the LTE UL interval 164, the AP (BB processor 154) may initiate a new transmission 184 or may initiate a subsequent LTE DL interval 160 (CTS- - using a self-process or any other suitable technique). This block (interval 172) should end at or subsequent to the beginning of the next UL guard interval 168. The AP must schedule the termination of the blocking interval 172 immediately following by the transmission burst 184 itself terminating at the end of the DL interval 160 or during the UL guard interval 168. [ In this case, the corresponding ACK 208 is received during the UL guard interval or during the subsequent UL interval 164.

In some embodiments, the Wi-Fi AP (BB processor 154) of the device 134 may determine that the STA 146 is in a state where the STA 146 is unable to send an acknowledgment message to this transmission during the downlink interval of the LTE connection. Lt; / RTI > This technique prevents interference from the ACK sent by the STA 146 to the LTE reception of the BB processor 150.

In some embodiments, the AP (BB processor 154) communicates with an additional Wi-Fi STA (e.g., STA 142) that is not near the AP (and therefore does not cause interference to LTE UE reception) . For example, BB processor 154 may schedule to communicate with another STA at any time (e.g., during LTE UL interval 164 or DL interval 160). When intercepting Wi-Fi (e.g., during interval 172 to prevent transmission of near-field STA 146), BB processor 154 selectively blocks only neighboring STAs 146 and allows other STAs to communicate (For example, CTS-to-self) with low power to transmit data.

In some embodiments, the BB processor 154 may prevent the Wi-Fi STA from blocking during the LTE DL interval 160 if the LTE DL signal is received at the BB processor 150 at a level above a certain threshold have.

In some cases, the LTE UL transmission signal (at interval 164) is lower than a certain threshold to ensure that the CCA mechanism of STA 146 is not activated. In some embodiments, the BB processor 154 initiates an LTE DL interval 160 by initiating (or blocking) an explicit Wi-Fi transmission to prevent the STA 146 from starting a new transmission burst 192 Can be protected. In this embodiment, the blocking operation must have priority over the attempt of the STA 146 to transmit another burst 192. This priority can be achieved, for example, by changing the AP random back-off process (per Carrier-Sense Multiple Access (MAC) protocol of Wi-Fi).

In some embodiments, the blocking scheme of FIG. 6 may be combined with the BSR-based scheme of FIGS. 2-4 to create a known period (usually long) without LTE UL data transmission.

In some embodiments, an LTE UE (BB processor 150) may be required to periodically perform measurements to monitor surrounding BSs (eNodeBs). In this embodiment, the LTE UE (BB processor 150 can inform the combined AP (BB processor 154) of the measurement interval and the AP can prevent the near STA 146 from transmitting during these intervals This additional protection mechanism may also be applied in the case of a sensitive LTE period such as a handover period or a known period used for transmitting system control information.

(Coexistence between combined WI-FI and LTE devices operating in SPS / DRX mode)

The LTE specification defines two mode-semi-persistent scheduling (SPS) and discontinuous reception (DRX) in which the UE operates in a scattered pattern of active periods to schedule overhead and / or battery power savings. SPS and DRX are specified in Section 5 of 3GPP TS 36.321 cited above. In both modes (either individually or applied together in the same UE), the UE is preconfigured in a pattern of active periods separated by an inactive period.

The pattern is synchronized between the UE and the BS so that the UE can predict the LTE subframe in which no uplink or downlink activity has occurred. Thus, the UE wakes up and communicates with the required BS during the active period while remaining in the sleep mode for the inactive period. For example, the pattern defines an active period of 1 ms every 20 mm, defines an active period of 5 ms every 15 ms, or defines any other suitable pattern.

Consider the system configuration of Figure 1 above. In some embodiments, an LTE BB processor 44 serving as an LTE UE is configured by the BS 28 to operate in the SPS and / or DRX mode. As part of this configuration, the BS configures the BB processor 44 with the desired pattern of active and inactive periods. The BB processor 44 provides the pattern to the Wi-Fi BB processor 48 (which may function as an STA or an AP) via a coexistence interface with additional information. The BB processor 48 uses this information to configure the Wi-Fi operation to reduce mutual interference.

In various embodiments, the BB processor 48 may configure its own Wi-Fi transmission and / or transmission of the opposite Wi-Fi endpoint (STA or AP 32). Configuring the AP or STA may include configuring the Wi-Fi transmission and / or receiver functions. This configuration can be used to prevent interference from the Wi-Fi transmission of the BB processor 48 to the LTE reception of the BB processor 44 and / or the interference from the LTE transmission of the BB processor 44 to the Wi-Fi reception of the BB processor 48 Can be reduced. To assist in this operation, the BB processor 44 typically provides LTE frame timing to the BB processor 48 via a coexistence interface. The Wi-Fi BB processor 48 synchronizes its internal time base with the LTE frame timing provided by the BB processor 44.

Generally, the BB processor 44 provides the information associated with the pattern to the BB processor 48 in advance to allow the BB processor 48 enough time to configure the Wi-Fi operation. For example, provided information such as which subframe is defined as active and defined as inactive, which of the active subframes is used for UE transmission (uplink) and which is used for UE reception (downlink) The type of signal to be transmitted or received, and / or any other suitable information.

In an exemplary embodiment, the BB processor 48 sets the timing of the Wi-Fi transmission based on a pattern of LTE activity and inactivity periods. The timing may be set locally for transmission of the BB processor 48 or set remotely (e.g., using a CTS-to-self process) for transmission of the AP or STA 32 that is facing it, Both can be set.

In one exemplary embodiment, the BB processor 48 may prevent Wi-Fi transmission during an active LTE period. In another embodiment, the BB processor 48 may prevent Wi-Fi transmissions to finer granularity and may allow the device 24, for example during the active period used for reception at the BB processor 44, Wi-Fi transmissions from the base station.

In some embodiments, an LTE UE (BB processor 44) is required to periodically perform measurements to monitor surrounding BSs (eNodeBs). In this embodiment, the LTE UE notifies the combined Wi-Fi device (BB processor 48) of the measurement interval, and the BB processor 48 reduces interference during the reported period.

In some embodiments, the pattern of active / inactivity periods is determined based on the current transmission power, the current MCS, the received power of the transmission on the opposite side, the amount of traffic transmitted, and / And is adjusted according to various system parameters for LTE and / or Wi-Fi channels.

7 is a flowchart schematically illustrating a method for LTE / Wi-Fi coexistence according to another embodiment of the present invention. The method begins with the BS 28 configuring the LTE UE (BB processor 44) in the device 24 in a pattern of active and inactive time periods in accordance with the SPS and / or DRX mode in the configuration step 210 do.

The Wi-Fi BB processor 48 synchronizes its internal time base with the LTE frame timing of the LTE BB processor 44 in a synchronization step 214. The LTE BB processor 44 provides a pattern of active and inactive time periods to the Wi-Fi BB processor 48 at a pattern notification step 218. [ The Wi-Fi BB processor 48 adjusts the Wi-Fi operation (its own local operation and / or the operation of the opposing Wi-Fi STA or AP) based on the pattern in the Wi-Fi coordination step 222. Tuning attempts to reduce or eliminate interference between LTE and Wi-Fi connections.

The configuration of the devices 24,134 shown in Figures 1 and 5 is an exemplary configuration, which is purely chosen for clarity of concept. In alternative embodiments, any other suitable device configuration is used. For example, LTE and Wi-Fi communications can be performed over separate antennas. As another example, the functions of the BB processors 44 and 48 or the BB processors 150 and 154 may be performed by a single BB processor. In this context. The BB processors 44 and 48 of FIG. 1 and the BB processors 150 and 154 of FIG. 5 are collectively referred to as a baseband circuit that performs the disclosed techniques. Certain elements of the device 24 or 134 may be implemented using hardware, such as using one or more ASICs (Application-Specific Integrated Circuits) or FPGAs (Field-Programmable Gate Arrays). Alternatively, some of the elements of device 24 or 134 may be implemented in software, or a combination of hardware and software elements.

In some embodiments, the functionality of the device 24 or 134 may be implemented using a general purpose computer programmed with software to perform the functions described herein. The software may be downloaded to the computer in electronic form via a network and, for example, or it may alternatively or additionally be provided and / or stored in a touchable medium that is not transient, such as magnetic, optical or electronic memory.

It is to be understood that the above-described embodiments have been cited by way of example and that the present invention is not limited to what has been particularly shown and described above. Rather, the scope of the invention includes combinations and subcombinations of the various features described above, as well as variations and modifications of the invention which will occur to those skilled in the art upon reading the foregoing description and which are not disclosed in the prior art. Documents incorporated by reference in this patent application are considered to be part of the present application, excluding the extent to which any term is defined in these integrated documents in a way that conflicts with the definitions made explicitly or implicitly herein. And only the definitions in this specification should be considered.

Claims (52)

In a wireless device, establishing a first connection with a base station (BS) of a long haul wireless data network and a second connection over a wireless local area network (WLAN);
Selecting, at the wireless device, a time interval for communicating over the second connection;
And for paging for transmission from the wireless device even when some data is pending for transmission to the BS in order to allow the BS to schedule the transmission of pending data outside the time interval in preparation for the selected time interval. ) Suppressing scheduling of data transmission from the wireless device to the BS over the first connection during the time interval by reporting to the BS before the time interval that there is no data;
Communicating with the wireless device over a second connection on the WLAN during the time interval; And
Reporting to the BS that the data is pending for transmission from the wireless device in preparation for the end of the time interval, reporting that the data is pending includes controlling the size of the scheduled transmission Reporting an amount of data that is different from the actual size of the panning data to do so;
The communication method comprising the steps of: 2. The method of claim 1, wherein the long-distance wireless data network operates in accordance with a Long Term Evolution (LTE) standard, and reporting that no pending data is present includes transmitting a buffer status report (BSR) message. Way. 2. The method of claim 1, further comprising: alternately reporting to the BS that there is pending data and no pending data, thereby applying a communication pattern that alternates between the first and second connections Communication method. 2. The method of claim 1, comprising inhibiting communication over the second connection after the selected time interval and subsequent to the selected time interval. 2. The method of claim 1, wherein reporting to the BS comprises sending a report message to the BS at a time that takes into account the scheduling latency of the first connection. A radio frequency (RF) front end configured to exchange RF signals for communication over a long distance wireless data network and a wireless local area network (WLAN); And
Establishing a first connection with a BS of a long haul wireless data network and a second connection over a WLAN via an RF front end, selecting a time interval for communicating over the second connection, By reporting to the BS before the time interval that there is no pending data for transmission from the wireless device even when some data is pending for transmission to the BS, so as to schedule the transmission of pending data outside the time interval, Thereby preventing scheduling data transmissions from the wireless device to the BS over the first connection during the time interval and communicating using the wireless device over the second connection on the WLAN during the time interval, In preparation for the end of the time interval, transmission from the wireless device And reporting the amount of data different than the actual size of the panning data to control the size of the scheduled transmission;
And the wireless device. 7. The base station of claim 6, wherein the long-range wireless data network operates in accordance with a Long Term Evolution (LTE) standard and the baseband circuit is configured to report a pending data by transmitting a buffer status report (BSR) Lt; / RTI > 7. The method of claim 6, wherein the baseband circuit is configured to apply alternating communication patterns between the first and second connections by alternately reporting to the BS that there is pending data and no pending data Gt; 7. The wireless device of claim 6, wherein the baseband circuit is configured to inhibit communication via the second connection prior to the selected time interval and subsequent to the selected time interval. 7. The wireless device of claim 6, wherein the baseband circuit is configured to send a reporting message to the BS reporting that there is no pending data at a time that takes into account the scheduling latency of the first connection. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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