Method and apparatus to facilitate support for multi-radio coexistence

A method includes identifying coexistence issues among radios in a User Equipment (UE). The method also includes submitting a message to a base station that requests reconfiguring of a timing schedule of a first one of the supported radios to provide for periods of inactivity of the first one of the supported radios. The inactive periods provide operating periods for at least a second one of the supported radios. The inactive periods may be measurement gaps.

TECHNICAL FIELD

The present description is related, generally, to multi-radio techniques and, more specifically, to coexistence techniques for multi-radio devices.

BACKGROUND

Some conventional advanced devices include multiple radios for transmitting/receiving using different Radio Access Technologies (RATs). Examples of RATs include, e.g., Universal Mobile Telecommunications System (UMTS), Global System for Mobile Communications (GSM), cdma2000, WiMAX, WLAN (e.g., WiFi), Bluetooth, LTE, and the like.

An example mobile device includes an LTE User Equipment (UE), such as a fourth generation (4G) mobile phone. Such 4G phone may include various radios to provide a variety of functions for the user. For purposes of this example, the 4G phone includes an LTE radio for voice and data, an IEEE 802.11 (WiFi) radio, a position location, e.g., Global Positioning System (GPS) radio, and a Bluetooth radio, where two of the above or all four may operate simultaneously. While the different radios provide useful functionalities for the phone, their inclusion in a single device gives rise to coexistence issues. Specifically, operation of one radio may in some cases interfere with operation of another radio through radiative, conductive, resource collision, and/or other interference mechanisms. Coexistence issues include such interference.

This is especially true for the LTE uplink channel, which is adjacent to the Industrial Scientific and Medical (ISM) band and may cause interference therewith The concept of coexistence addresses techniques for operating multiple radios in the same device in a manner that reduces or minimizes interference therebetween. Coexistence issues exist when radios see interference from each other. It is noted that Bluetooth and some Wireless LAN (WLAN) channels fall within the ISM band. In some instances, a Bluetooth error rate can become unacceptable when LTE is active in some channels of Band 7 or even Band 40 for some Bluetooth channel conditions. Even though there is no significant degradation to LTE, simultaneous operation with Bluetooth can result in disruption in voice services terminating in a Bluetooth headset. Such disruption may be unacceptable to the consumer. A similar issue exists when LTE transmissions interfere with position location. Currently, there is no mechanism that can solve this issue because LTE by itself does not experience any degradation

With reference specifically to LTE, it is noted that a UE communicates with an evolved NodeB (eNB; e.g., a base station for a wireless communications network) to inform the eNB of interference seen by the UE on the downlink. Furthermore, the eNB may be able to estimate interference at the UE using a downlink error rate. In some instances, the eNB and the UE can cooperate to find a solution that reduces interference at the UE, even interference due to radios within the UE itself. However, in conventional LTE, the interference estimates regarding the downlink may not be adequate to comprehensively address interference.

In one instance, an LTE uplink signal interferes with a Bluetooth signal or WLAN signal. However, such interference is not reflected in the downlink measurement reports at the eNB. As a result, unilateral action on the part of the UE (e.g., moving the uplink signal to a different channel) may be thwarted by the eNB, which is not aware of the uplink coexistence issue and seeks to undo the unilateral action. For instance, even if the UE re-establishes the connection on a different frequency channel, the network can still handover the UE back to the original frequency channel that was corrupted by the in-device interference. This is a likely scenario because the desired signal strength on the corrupted channel may sometimes be higher than reflected in the measurement reports of the new channels based on Reference Signal Received Power (RSRP) to the eNB. Hence, a ping-pong effect of being transferred back and forth between the corrupted channel and the desired channel can happen if the eNB uses RSRP reports to inform handover decisions.

Other unilateral action on the part of the UE, such as simply stopping uplink communications without coordination of the eNB may cause power loop malfunctions at the eNB. Additional issues that exist in conventional LTE include a general lack of ability on the part of the UE to suggest desired configurations as an alternative to configurations that have coexistence issues. For at least these reasons, uplink coexistence issues at the UE may remain unresolved for a long time period, degrading performance and efficiency of other radios at the UE.

BRIEF SUMMARY

According to one aspect, a method for use in a wireless communication system includes identifying coexistence issues among radios in a User Equipment (UE). The method also includes submitting a first message to a base station that affects reconfiguration of a timing schedule of a first one of the radios to provide for periods of inactivity of the first one of the radios. The inactivity periods provide operating periods for at least a second one of the radios.

In another aspect, a User Equipment (UE) for use in a wireless communication system includes a memory, and a processor coupled to the memory. The processor is configured to identify coexistence issues among radios in a User Equipment (UE). The processor is also configured to submit a first message to a base station that affects reconfiguration of a timing schedule of a first one of the radios to provide for periods of inactivity of the first one of the radios. The inactivity periods provide operating periods for at least a second one of the radios.

In yet another aspect, a computer readable medium tangibly stores program code. The code identifies coexistence issues among radios in a User Equipment (UE). The code also submits a first message to a base station that affects reconfiguration of a timing schedule of a first one of the radios to provide for periods of inactivity of the first one of the radios. The inactivity periods provide operating periods for at least a second one of the radios.

In still another aspect, a wireless communication system has means for identifying coexistence issues among radios in a User Equipment (UE). The system also has means for submitting a first message to a base station that affects reconfiguration of a timing schedule of a first one of the radios to provide for periods of inactivity of the first one of the radios. The inactivity periods provide operating periods for at least a second one of the radios.

In another aspect, a method for communicating in a wireless communication system includes receiving a coexistence indication message from a user equipment (UE) having multiple radios. The coexistence indication message indicates a coexistence issue for at least one of the radios of the UE. The method also includes providing periods of inactivity for at least one of the radios of the UE, associated with the coexistence issue, in response to receiving the coexistence indication.

According to another aspect, a wireless communication system has means for receiving a coexistence indication message from a user equipment (UE) having multiple radios. The coexistence indication message indicates a coexistence issue for at least one of the radios of the UE. The system also has means for providing periods of inactivity for at least one of the radios of the UE, associated with the coexistence issue, in response to receiving the coexistence indication.

In a further aspect, a base station for use in a wireless communication system has a memory and a processor coupled to the memory. The processor is configured to receive a coexistence indication message from a user equipment (UE) having multiple radios. The coexistence indication message indicates a coexistence issue for at least one of the radios of the UE. The processor is also configured to provide periods of inactivity for at least one of the radios of the UE, associated with the coexistence issue, in response to receiving the coexistence indication

DETAILED DESCRIPTION

Various aspects of the disclosure provide techniques to mitigate coexistence issues in multi-radio devices. As explained above, some coexistence issues persist because an eNB is not aware of interference on the UE side that is experienced by other radios. According to one aspect, a UE identifies existing or potential coexistence issues and sends a message to the eNB. The message requests one or more parameters to reconfigure a timing schedule of an LTE radio to provide for periods of inactivity of the LTE radio during which another radio can operate. The message to the eNB can include an identification of resources experiencing coexistence issues, an identification of desired parameters, a reason for the coexistence issues, or any other helpful information. If the eNB then grants the request, the UE configures its timing according to the parameters.

Single carrier frequency division multiple access (SC-FDMA), which utilizes single carrier modulation and frequency domain equalization is a technique that can be utilized with various aspects described herein. SC-FDMA has similar performance and essentially the same overall complexity as those of an OFDMA system. SC-FDMA signal has lower peak-to-average power ratio (PAPR) because of its inherent single carrier structure. SC-FDMA has drawn great attention, especially in the uplink communications where lower PAPR greatly benefits the mobile terminal in terms of transmit power efficiency. It is currently a working assumption for an uplink multiple access scheme in 3GPP Long Term Evolution (LTE), or Evolved UTRA.

Referring toFIG. 1, a multiple access wireless communication system according to one aspect is illustrated. An evolved Node B100(eNB) includes a computer115that has processing resources and memory resources to manage the LTE communications by allocating resources and parameters, granting/denying requests from user equipment, and/or the like. The eNB100also has multiple antenna groups, one group including antenna104and antenna106, another group including antenna108and antenna110, and an additional group including antenna112and antenna114. InFIG. 1, only two antennas are shown for each antenna group, however, more or fewer antennas can be utilized for each antenna group. A User Equipment (UE)116(also referred to as an Access Terminal (AT)) is in communication with antennas112and114, while antennas112and114transmit information to the UE116over an uplink (UL)188. The UE122is in communication with antennas106and108, while antennas106and108transmit information to the UE122over a downlink (DL)126and receive information from the UE122over an uplink124. In an FDD system, communication links118,120,124and126can use different frequencies for communication. For example, the downlink120can use a different frequency than used by the uplink118.

Each group of antennas and/or the area in which they are designed to communicate is often referred to as a sector of the eNB. In this aspect, respective antenna groups are designed to communicate to UEs in a sector of the areas covered by the eNB100.

In communication over the downlinks120and126, the transmitting antennas of the eNB100utilize beamforming to improve the signal-to-noise ratio of the uplinks for the different UEs116and122. Also, an eNB using beamforming to transmit to UEs scattered randomly through its coverage causes less interference to UEs in neighboring cells than a UE transmitting through a single antenna to all its UEs.

An eNB can be a fixed station used for communicating with the terminals and can also be referred to as an access point, base station, or some other terminology. A UE can also be called an access terminal, a wireless communication device, terminal, or some other terminology.

FIG. 2is a block diagram of an aspect of a transmitter system210(also known as an eNB) and a receiver system250(also known as a UE) in a MIMO system200. In some instances, both a UE and an eNB each have a transceiver that includes a transmitter system and a receiver system. At the transmitter system210, traffic data for a number of data streams is provided from a data source212to a transmit (TX) data processor214.

A MIMO system supports time division duplex (TDD) and frequency division duplex (FDD) systems. In a TDD system, the uplink and downlink transmissions are on the same frequency region so that the reciprocity principle allows the estimation of the downlink channel from the uplink channel. This enables the eNB to extract transmit beamforming gain on the downlink when multiple antennas are available at the eNB.

The coded data for each data stream can be multiplexed with pilot data using OFDM techniques. The pilot data is a known data pattern processed in a known manner and can be used at the receiver system to estimate the channel response. The multiplexed pilot and coded data for each data stream is then modulated (e.g., symbol mapped) based on a particular modulation scheme (e.g., BPSK, QSPK, M-PSK, or M-QAM) selected for that data stream to provide modulation symbols. The data rate, coding, and modulation for each data stream can be determined by instructions performed by a processor230operating with a memory232.

The modulation symbols for respective data streams are then provided to a TX MIMO processor220, which can further process the modulation symbols (e.g., for OFDM). The TX MIMO processor220then provides NTmodulation symbol streams to NTtransmitters (TMTR)222athrough222t. In certain aspects, the TX MIMO processor220applies beamforming weights to the symbols of the data streams and to the antenna from which the symbol is being transmitted.

An RX data processor260then receives and processes the NRreceived symbol streams from NRreceivers254based on a particular receiver processing technique to provide NR“detected” symbol streams. The RX data processor260then demodulates, deinterleaves, and decodes each detected symbol stream to recover the traffic data for the data stream. The processing by the RX data processor260is complementary to the processing performed by the TX MIMO processor220and the TX data processor214at the transmitter system210.

A processor270(operating with a memory272) periodically determines which pre-coding matrix to use (discussed below). The processor270formulates an uplink message having a matrix index portion and a rank value portion.

The uplink message can include various types of information regarding the communication link and/or the received data stream. The uplink message is then processed by a TX data processor238, which also receives traffic data for a number of data streams from a data source236, modulated by a modulator280, conditioned by transmitters254athrough254r, and transmitted back to the transmitter system210.

At the transmitter system210, the modulated signals from the receiver system250are received by antennas224, conditioned by receivers222, demodulated by a demodulator240, and processed by an RX data processor242to extract the uplink message transmitted by the receiver system250. The processor230then determines which pre-coding matrix to use for determining the beamforming weights, then processes the extracted message.

FIG. 3is a block diagram conceptually illustrating an exemplary frame structure in downlink Long Term Evolution (LTE) communications. The transmission timeline for the downlink may be partitioned into units of radio frames. Each radio frame may have a predetermined duration (e.g., 10 milliseconds (ms)) and may be partitioned into 10 subframes with indices of 0 through 9. Each subframe may include two slots. Each radio frame may thus include 20 slots with indices of 0 through 19. Each slot may include L symbol periods, e.g., 7 symbol periods for a normal cyclic prefix (as shown inFIG. 3) or 6 symbol periods for an extended cyclic prefix. The 2L symbol periods in each subframe may be assigned indices of 0 through 2L-1. The available time frequency resources may be partitioned into resource blocks. Each resource block may cover N subcarriers (e.g., 12 subcarriers) in one slot.

In LTE, an eNB may send a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) for each cell in the eNB. The PSS and SSS may be sent in symbol periods6and5, respectively, in each of subframes0and5of each radio frame with the normal cyclic prefix, as shown inFIG. 3. The synchronization signals may be used by UEs for cell detection and acquisition. The eNB may send a Physical Broadcast Channel (PBCH) in symbol periods0to3in slot1of subframe0. The PBCH may carry certain system information.

The eNB may send a Cell-specific Reference Signal (CRS) for each cell in the eNB. The CRS may be sent in symbols0,1, and4of each slot in case of the normal cyclic prefix, and in symbols0,1, and3of each slot in case of the extended cyclic prefix. The CRS may be used by UEs for coherent demodulation of physical channels, timing and frequency tracking, Radio Link Monitoring (RLM), Reference Signal Received Power (RSRP), and Reference Signal Received Quality (RSRQ) measurements, etc.

The eNB may send a Physical Control Format Indicator Channel (PCFICH) in the first symbol period of each subframe, as seen inFIG. 3. The PCFICH may convey the number of symbol periods (M) used for control channels, where M may be equal to 1, 2 or 3 and may change from subframe to subframe. M may also be equal to 4 for a small system bandwidth, e.g., with less than 10 resource blocks. In the example shown inFIG. 3, M=3. The eNB may send a Physical HARQ Indicator Channel (PHICH) and a Physical Downlink Control Channel (PDCCH) in the first M symbol periods of each subframe. The PDCCH and PHICH are also included in the first three symbol periods in the example shown inFIG. 3. The PHICH may carry information to support Hybrid Automatic Repeat Request (HARM). The PDCCH may carry information on resource allocation for UEs and control information for downlink channels. The eNB may send a Physical Downlink Shared Channel (PDSCH) in the remaining symbol periods of each subframe. The PDSCH may carry data for UEs scheduled for data transmission on the downlink. The various signals and channels in LTE are described in 3GPP TS 36.211, entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation,” which is publicly available.

A number of resource elements may be available in each symbol period. Each resource element may cover one subcarrier in one symbol period and may be used to send one modulation symbol, which may be a real or complex value. Resource elements not used for a reference signal in each symbol period may be arranged into resource element groups (REGs). Each REG may include four resource elements in one symbol period. The PCFICH may occupy four REGs, which may be spaced approximately equally across frequency, in symbol period0. The PHICH may occupy three REGs, which may be spread across frequency, in one or more configurable symbol periods. For example, the three REGs for the PHICH may all belong in symbol period0or may be spread in symbol periods0,1and2. The PDCCH may occupy 9, 18, 32 or 64 REGs, which may be selected from the available REGs, in the first M symbol periods. Only certain combinations of REGs may be allowed for the PDCCH.

A UE may be assigned resource blocks in the control section to transmit control information to an eNB. The UE may also be assigned resource blocks in the data section to transmit data to the eNodeB. The UE may transmit control information in a Physical Uplink Control Channel (PUCCH) on the assigned resource blocks in the control section. The UE may transmit only data or both data and control information in a Physical Uplink Shared Channel (PUSCH) on the assigned resource blocks in the data section. An uplink transmission may span both slots of a subframe and may hop across frequency as shown inFIG. 4.

The PSS, SSS, CRS, PBCH, PUCCH and PUSCH in LTE are described in 3GPP TS 36.211, entitled “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation,” which is publicly available.

In an aspect, described herein are systems and methods for providing support within a wireless communication environment, such as a 3GPP LTE environment or the like, to facilitate multi-radio coexistence solutions.

Referring now toFIG. 5, illustrated is an example wireless communication environment500in which various aspects described herein can function. The wireless communication environment500can include a wireless device510, which can be capable of communicating with multiple communication systems. These systems can include, for example, one or more cellular systems520and/or530, one or more WLAN systems540and/or550, one or more wireless personal area network (WPAN) systems560, one or more broadcast systems570, one or more satellite positioning systems580, other systems not shown inFIG. 5, or any combination thereof. It should be appreciated that in the following description the terms “network” and “system” are often used interchangeably.

The cellular systems520and530can each be a CDMA, TDMA, FDMA, OFDMA, Single Carrier FDMA (SC-FDMA), or other suitable system. A CDMA system can implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. Moreover, cdma2000 covers IS-2000 (CDMA2000 1X), IS-95 and IS-856 (HRPD) standards. A TDMA system can implement a radio technology such as Global System for Mobile Communications (GSM), Digital Advanced Mobile Phone System (D-AMPS), etc. An OFDMA system can implement a radio technology such as Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM®, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named “3rdGeneration Partnership Project” (3GPP). cdma2000 and UMB are described in documents from an organization named “3rdGeneration Partnership Project 2” (3GPP2). In an aspect, the cellular system520can include a number of base stations522, which can support bi-directional communication for wireless devices within their coverage. Similarly, the cellular system530can include a number of base stations532that can support bi-directional communication for wireless devices within their coverage.

WLAN systems540and550can respectively implement radio technologies such as IEEE 802.11 (WiFi), Hiperlan, etc. The WLAN system540can include one or more access points542that can support bi-directional communication. Similarly, the WLAN system550can include one or more access points552that can support bi-directional communication. The WPAN system560can implement a radio technology such as Bluetooth (BT), IEEE 802.15, etc. Further, the WPAN system560can support bi-directional communication for various devices such as wireless device510, a headset562, a computer564, a mouse566, or the like.

The broadcast system570can be a television (TV) broadcast system, a frequency modulation (FM) broadcast system, a digital broadcast system, etc. A digital broadcast system can implement a radio technology such as MediaFLO™, Digital Video Broadcasting for Handhelds (DVB-H), Integrated Services Digital Broadcasting for Terrestrial Television Broadcasting (ISDB-T), or the like. Further, the broadcast system570can include one or more broadcast stations572that can support one-way communication.

The satellite positioning system580can be the United States Global Positioning System (GPS), the European Galileo system, the Russian GLONASS system, the Quasi-Zenith Satellite System (QZSS) over Japan, the Indian Regional Navigational Satellite System (IRNSS) over India, the Beidou system over China, and/or any other suitable system. Further, the satellite positioning system580can include a number of satellites582that transmit signals for position determination.

In an aspect, the wireless device510can be stationary or mobile and can also be referred to as a user equipment (UE), a mobile station, a mobile equipment, a terminal, an access terminal, a subscriber unit, a station, etc. The wireless device510can be cellular phone, a personal digital assistance (PDA), a wireless modem, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, etc. In addition, a wireless device510can engage in two-way communication with the cellular system520and/or530, the WLAN system540and/or550, devices with the WPAN system560, and/or any other suitable systems(s) and/or devices(s). The wireless device510can additionally or alternatively receive signals from the broadcast system570and/or satellite positioning system580. In general, it can be appreciated that the wireless device510can communicate with any number of systems at any given moment. Also, the wireless device510may experience coexistence issues among various ones of its constituent radio devices that operate at the same time. Accordingly, the wireless device510includes a coexistence manager (CxM, not shown) that has a functional module to detect and mitigate coexistence issues, as explained further below.

Turning next toFIG. 6, a block diagram is provided that illustrates an example design for a multi-radio wireless device600and may be used as an implementation of the wireless device510ofFIG. 5. AsFIG. 6illustrates, the wireless device600can include N radios620athrough620n, which can be coupled to N antennas610athrough610n, respectively, where N can be any integer value. It should be appreciated, however, that respective radios620can be coupled to any number of antennas610and that multiple radios620can also share a given antenna610.

In general, a radio620can be a unit that radiates or emits energy in an electromagnetic spectrum, receives energy in an electromagnetic spectrum, or generates energy that propagates via conductive means. By way of example, a radio620can be a unit that transmits a signal to a system or a device or a unit that receives signals from a system or device. Accordingly, it can be appreciated that a radio620can be utilized to support wireless communication. In another example, a radio620can also be a unit (e.g., a screen on a computer, a circuit board, etc.) that emits noise, which can impact the performance of other radios. Accordingly, it can be further appreciated that a radio620can also be a unit that emits noise and interference without supporting wireless communication.

In an aspect, respective radios620can support communication with one or more systems. Multiple radios620can additionally or alternatively be used for a given system, e.g., to transmit or receive on different frequency bands (e.g., cellular and PCS bands).

In another aspect, a digital processor630can be coupled to radios620athrough620nand can perform various functions, such as processing for data being transmitted or received via the radios620. The processing for each radio620can be dependent on the radio technology supported by that radio and can include encryption, encoding, modulation, etc., for a transmitter; demodulation, decoding, decryption, etc., for a receiver, or the like. In one example, the digital processor630can include a CxM640that can control operation of the radios620in order to improve the performance of the wireless device600as generally described herein. The CxM640can have access to a database644, which can store information used to control the operation of the radios620. As explained further below, the CxM640can be adapted for a variety of techniques to decrease interference between the radios. In one example, the CxM640requests a measurement gap pattern or DRX cycle that allows an ISM radio to communicate during periods of LTE inactivity.

For simplicity, digital processor630is shown inFIG. 6as a single processor. However, it should be appreciated that the digital processor630can include any number of processors, controllers, memories, etc. In one example, a controller/processor650can direct the operation of various units within the wireless device600. Additionally or alternatively, a memory652can store program codes and data for the wireless device600. The digital processor630, controller/processor650, and memory652can be implemented on one or more integrated circuits (ICs), application specific integrated circuits (ASICs), etc. By way of specific, non-limiting example, the digital processor630can be implemented on a Mobile Station Modem (MSM) ASIC.

In an aspect, the CxM640can manage operation of respective radios620utilized by wireless device600in order to avoid interference and/or other performance degradation associated with collisions between respective radios620. CxM640may perform one or more processes, such as those illustrated inFIGS. 11,13, and14. By way of further illustration, a graph700inFIG. 7represents respective potential collisions between seven example radios in a given decision period. In the example shown in graph700, the seven radios include a WLAN transmitter (Tw), an LTE transmitter (Tl), an FM transmitter (Tf), a GSM/WCDMA transmitter (Tc/Tw), an LTE receiver (Rl), a Bluetooth receiver (Rb), and a GPS receiver (Rg). The four transmitters are represented by four nodes on the left side of the graph700. The four receivers are represented by three nodes on the right side of the graph700.

A potential collision between a transmitter and a receiver is represented on the graph700by a branch connecting the node for the transmitter and the node for the receiver. Accordingly, in the example shown in the graph700, collisions may exist between (1) the WLAN transmitter (Tw) and the Bluetooth receiver (Rb); (2) the LTE transmitter (Tl) and the Bluetooth receiver (Rb); (3) the WLAN transmitter (Tw) and the LTE receiver (Rl); (4) the FM transmitter (Tf) and the GPS receiver (Rg); (5) a WLAN transmitter (Tw), a GSM/WCDMA transmitter (Tc/Tw), and a GPS receiver (Rg).

In one aspect, an example CxM640can operate in time in a manner such as that shown by diagram800inFIG. 8. As diagram800illustrates, a timeline for CxM operation can be divided into Decision Units (DUs), which can be any suitable uniform or non-uniform length (e.g., 100 μs) where notifications are processed, and a response phase (e.g., 20 μs) where commands are provided to various radios620and/or other operations are performed based on actions taken in the evaluation phase. In one example, the timeline shown in the diagram800can have a latency parameter defined by a worst case operation of the timeline, e.g., the timing of a response in the case that a notification is obtained from a given radio immediately following termination of the notification phase in a given DU.

In-device coexistence problems can exist for a UE between resources such as, for example, LTE and ISM bands (e.g., for Bluetooth/WLAN). In current LTE implementations, any interference issues to LTE are reflected in the DL measurements (e.g., Reference Signal Received Quality (RSRQ) metrics, etc.) reported by the UE and/or the DL error rate which the eNB can use to make inter-frequency or inter-RAT handoff decisions to, e.g., move LTE to a channel or RAT with no coexistence issues. However, it can be appreciated that these existing techniques will not work if, for example, the LTE UL is causing interference to Bluetooth/WLAN but the LTE DL does not see any interference from Bluetooth/WLAN. More particularly, even if the UE autonomously moves itself to another channel on the UL, the eNB can in some cases handover the UE back to the problematic channel for load balancing purposes. In any case, it can be appreciated that existing techniques do not facilitate use of the bandwidth of the problematic channel in the most efficient way.

Turning now toFIG. 9, a block diagram of a system900for providing support within a wireless communication environment for multi-radio coexistence management is illustrated. In an aspect, the system900can include one or more UEs910and/or eNBs930, which can engage in UL, DL, and/or any other suitable communication with each other and/or any other entities in the system900. In one example, the UE910and/or eNB930can be operable to conduct communication using a variety of radio technologies and/or resources, some of which can potentially be colliding. Thus, the UE910can utilize various techniques for managing coexistence between multiple radios utilized by the UE910, as generally described herein.

To mitigate at least the above shortcomings, the UE910can utilize respective features described herein and illustrated by the system900to facilitate support for multi-radio coexistence within the UE910. According to various aspects disclosed herein, a UE may request timing schedules from the eNB that allow another radio, such as a Bluetooth radio, to be active during times when LTE communications of the UE are inactive.

In one example, a new message can be provided from the UE to the eNB that allows the UE to request parameters or a range of parameters associated with a measurement gap pattern and/or a discontinuous reception (DRX) mode. The message can also indicate release of these settings. In another example, new specific gap patterns are described for Time Division Multiplexing (TDM) solutions between LTE and BT/WLAN. New specific DRX mode parameters are also described. In another example, UL HARQ can be modified at the UE and eNB to prevent UE transmissions beyond an active time in DRX.

In a first aspect, a handover request module912and/or other mechanisms associated with the UE910can be configured to provide a message to the eNB930that allows the UE910to request an inter-frequency or inter-RAT handover. Such aspect is described in more detail in United State patent application Ser. No. 12/851,302, filed concurrently herewith and entitled “METHOD AND APPARATUS TO FACILITATE SUPPORT FOR MULTI-RADIO COEXISTENCE,” the disclosure of which is expressly incorporated by reference herein in its entirety.

In a second aspect, a parameter request module916and/or other mechanisms associated with the UE910can be configured to provide a message to the eNB930that allows the UE910to request the parameters and/or a range of parameters associated with the measurement gap pattern and/or DRX mode used within the system900. In one example, such a message can also indicate release of these settings, such as when a coexistence issue has passed.

With respect to messages provided by the handover request module912and/or parameter request module916to eNB930, a request analyzer932and/or other means associated with the eNB930can analyze a received request and determine whether a UE910from which the request is received is utilizing a problematic frequency band and/or other resources. In the event the UE910is determined to be utilizing problematic resources, a resource grant module934and/or a parameter assignment module936can be utilized by the eNB930to grant resources associated with a requested handover and/or a requested set of measurement gap or DRX parameters, respectively.

In a third aspect, a gap pattern controller918and/or other mechanisms associated with the UE910can utilize one or more new specific gap patterns (e.g., as obtained via the parameter request module916or other appropriate means), which can be provided for, e.g., TDM solutions between LTE and Bluetooth/WLAN.

Similarly, in a fourth aspect, a DRX controller918and/or other mechanisms associated with the UE910can facilitate operation of the UE910according to one or more new specific DRX mode parameters (e.g., as obtained via the parameter request module916or other appropriate means).

In a fifth aspect, UL HARQ can be modified at the UE910and/or the eNB930(e.g., via a HARQ timing module922at UE910and/or the eNB930) in order to prevent transmissions by the UE910beyond a predefined time in DRX.

Conventional LTE provides for measurement gaps. An eNB may instruct a UE to be silent (i.e., no uplink or downlink communications) every so many milliseconds of a cycle. Gaps currently provided for include 6 ms out of every 40 ms and 6 ms out of every 80 ms. During the measurement gap, the UE measures interfering signals in various channels. The UE then reports the information to the eNB, and the eNB uses the reported information, e.g., to handover the LTE communications of the UE to another channel that should be expected to experience less interference. Measurement gap configuration is initiated by the eNB in conventional LTE systems.

In some aspects, new gap patterns are defined for the measurement gaps, where such new gap patterns provide evenly-distributed gaps that can be utilized by another radio. One example pattern includes 20 ms out of 40 ms, and another example includes 30 ms out of 60 ms. In such example gap patterns, half of each cycle is a measurement gap and can be used by other radios. For instance, according to one example, 20 ms of every 40 ms period can be used by a Bluetooth radio (and/or other radios) without LTE interference. Examples for implementing such measurement gap patterns are described in more detail below. In another aspect, measurement gap patterns can be configured in a process initiated by a UE, which contrasts with conventional LTE systems which only allow eNB initiation of measurement gap configuration.

FIG. 10illustrates example call flow diagrams1010,1020showing use of messages according to one aspect. In this example, new tools are added to the Radio Resource Control (RRC) connection messaging that is provided by conventional LTE. RRC protocol handles the Layer 3 control plane signaling and controls behavior of the UE1003including System Information (SI) broadcasting, connection control such as handover within LTE, network-controlled inter-Radio Access Technology (RAT) mobility and measurement configuration and reporting. In one instance, an RRCConnectionRequest message (not shown) is sent from a UE to an eNB to initiate an LTE communication.

In one aspect, a new reconfiguration request message1001(e.g., a RRCConnectionReconfigurationRequest message) is added to an LTE communication system and is sent from a UE1003to an eNB1005to initiate a reconfiguration of measurement gaps. In the scenario1010, a measurement gap reconfiguration request is sent from the UE1003to the eNB1005, and the request is successful. Specifically, the reconfiguration request message1001is sent to the eNB1005to initiate a measurement gap reconfiguration. The reconfiguration request message1001can include a reason for the request (e.g., Bluetooth ON), a range of requested parameters (e.g., indications of one or more requested measurement gap patterns), and/or any other useful information.

The eNB1005processes the request. In some aspects, when it is indicated that the UE1003has coexistence issues, the eNB grants the request if the requested configuration is possible. In the scenario1010, the eNB1005grants the request by adopting the proposed measurement gap pattern. The connection reconfiguration message1007(e.g., a RRCConnectionReconfiguration message) is sent from the eNB1005to the UE1003informing the UE1003, e.g., of the request grant and instructing the UE to conform to the measurement gap pattern. The UE1003then reconfigures its parameters, and when it has completed reconfiguration, the UE1003sends the configuration completed message1009(e.g., a RRCConnectionReconfigurationComplete message) back to the eNB1005.

The process illustrated in the scenario1010differs from conventional LTE processes. For instance, the UE1003is given some ability to direct its own operation through use of the reconfiguration request message1001, which can suggest parameters to help resolve a coexistence issue. Additionally, when interference affects an uplink signal but not a downlink signal (and, thus, the eNB1005is unaware of the coexistence issue), the UE1003initiates the reconfiguration, thereby assuring action is taken in response to the coexistence issue. By contrast, in conventional LTE only the eNB1005initiates configuration of measurement gaps. Also, the eNB1005is given more information regarding interference than in some conventional LTE systems. For instance, in conventional systems, there is no technique for the eNB to become aware of the timing of other radios in a UE or to become aware that another UE radio has turned ON/OFF. In various aspects of the disclosure, the reconfiguration request and/or other signaling from the UE can provide such information to the eNB.

In the scenario1020, the eNB1005rejects the reconfiguration request in message1001. The eNB1005sends a request reject message1011(e.g., a RRCConnectionReconfigurationRequestReject message) to the UE1003informing the UE1003that the request is rejected. The UE1003can then send a follow-up reconfiguration request message1013to either request the same parameters again or to request parameters different than in the first request. In one example, when a request for a measurement gap reconfiguration is rejected, the UE1003may follow up by requesting a different measurement gap pattern.

Various examples can be adapted for any of a variety of scenarios that may occur during LTE operation. For instance, when an RRC connection is not already in place, a connection request message (e.g., a RRCConnectionRequest message, not shown) can include much of the information discussed above (e.g., requested parameters, a reason for the request, etc.). The eNB uses the information in the connection request message to know that a coexistence issue exists and to assign a configuration to the UE to reduce or minimize coexistence issues when LTE activity is initiated.

An example of when an RRC connection is not already in place includes a scenario when a user is not currently making a phone call. When the user places the call, the RRC connection is established. An example of when an RRC connection is in place includes a scenario when a user is currently on an established call. In either case, an appropriate message is selected based on whether the RRC connection is in place. Also in either case, if the user uses Bluetooth while on the call, coexistence issues may present themselves.

In yet another example, the UE1003can be configured to send a message to the eNB when certain events occur. For instance, if an LTE transfer is ongoing and another radio transfer becomes active (e.g., Bluetooth), the UE1003can send a reconfiguration request message. If another radio transfer is ongoing (e.g., Bluetooth) and LTE becomes active, a connection request message can be sent that includes a request for certain parameters. Furthermore, after a condition terminates (e.g., after Bluetooth or WLAN turns off), a message (not shown) may be sent by the UE1003to the eNB1005alerting the eNB1005that the coexistence issue no longer exists. Such message may be referred to as a “release indication” in some examples.

Configuration of measurement gap patterns is one example of a technique that can be used to provide TDM mitigation of coexistence issues. Another example includes setting Discontinuous Reception (DRX) timing parameters to facilitate other radio communication when LTE communication is inactive.

FIG. 11is an example of a DRX timing diagram according to conventional LTE. DRX includes the periodic switching off of an LTE receiver on the downlink, usually for power saving purposes. In conventional LTE, an eNB configures a DRX cycle for a UE. During the DRX cycle, the eNB knows times when the UE is on and listens for downlink communication and when the UE is off and does not listen for downlink communications. Uplink communications may proceed, even if the downlink communications are in an off period.

InFIG. 11, a full DRX cycle is labeled. During the onDuration, downlink communications are active and occur as they would in non-DRX communications. The PDCCH may include, e.g., a downlink grant, a PHICH, or the like.

However, the UE does not stop downlink communications entirely after the onDuration concludes. The active time includes both the onDuration and an inactivity timer, where the inactivity timer provides a reduced or minimum number of subframes where downlink communications may be possible from the eNB to the UE and the UE stays awake during this period. The active time is the portion of the total DRX cycle when the UE does not shut itself down.

For purposes of this discussion, the following parameters apply. The onDurationTimer is a number of subframes the UE shall monitor in a DRX cycle, and it defines the onDuration. The drx-InactivityTimer is a number of consecutive subframes that the UE monitors after receiving an initial uplink or downlink assignment, and it defines the inactivity period. The HARQ RTTtimer is the minimum number of subframes before retransmission is expected (e.g., 8 for FDD; >8 for TDD). The drx-RetransmissionTimer is the maximum number of subframes for the UE to monitor after HARQ RTT. The drxStartOffset parameter specifies an offset subframe where onDuration starts. ShortDRX-Cycle and LongDRXCycle are lengths of short and long DRX periods between onDuration times.FIG. 11shows only a long DRX cycle. The drxShortCycleTimer is the number of subframes to follow a short DRX before switching to long DRX.

An example of how the times inFIG. 11are used is illustrative. If the PDCCH gives a downlink grant, but the grant is not successful, then the UE sends a NACK in the RTT period (four subframes later). Then four additional subframes later, a retransmission is sent from the eNB during the retransmission timer period.

In another instance, if no downlink grant is received, the UE stays on for a period of time sufficient to receive the downlink grant after the onDuration ends. Such period may even last until the next onDuration. In any event, such illustrations show that in conventional LTE, the UE may stay awake for significant periods after the onDuration.

Various aspects presented herein provide for different values of parameters than those currently supported in conventional LTE. Such parameter values can be used to create time periods in which no downlink communications are sent to the UE, and no uplink communications are sent from the UE. Various aspects also allow a UE to request such parameters and to initiate configuration of such DRX cycles. In yet another aspect, eNB behavior is changed so that the UE is not expected to transmit on the uplink during periods of silence.

FIG. 12is an illustration of an exemplary DRX cycle according to one aspect of the disclosure. The shortDRXcycle parameter is zero so that only a long DRX cycle is used. The drx-InactivityTimer and drx-RestransmissionTimer parameters are set to zero to remove the additional active time to wait for downlink grants.

In some cases, four additional subframes are used after the onDuration for an uplink grant received in the last subframe of the onDuration or the PHICH of an uplink transmission in the last subframe of the onDuration. In other words, after the onDuration, the UE receives no more activity grants until the next onDuration. However, if the UE gets an uplink grant, then the UE will send something on the uplink during the 4 ms period after the onDuration.

In one example, the onDuration and 4 ms period following can be used by an LTE radio, while the time until the next onDuration can be used by another radio, such as a Bluetooth or WLAN radio. For instance, in one example based on these settings, LTE and Bluetooth/WLAN can utilize TDM with 34 ms for LTE and 30 ms for Bluetooth/WLAN, out of a 64 ms DRX cycle. Thus, the DRX cycle is shared in approximate halves between LTE and ISM, where the 4 ms period after onDuration is in the range of 1/16 of the DRX cycle length.

In an aspect, if the eNB sends a NACK for any of the last four uplink subframes of onDuration, the HARQ packet can be considered as terminated in error by both eNB and the UE. In other words, if there is an unsuccessful uplink transmission in the last four subframes of the onDuration, then a NACK is sent to the UE four subframes later in the active time. In conventional LTE, the UE will retransmit 4 ms after receiving the NACK; however, in some present aspects, it is desirable for the UE not to transmit after the active period ends. Accordingly, inFIG. 12, the eNB and the UE have negotiated a timeline such that if a NACK is sent to the UE, the UE will not retransmit. The packet is then terminated in error by both the UE and the eNB. Thus, the UE does not transmit after the end of the active period, and the eNB can be made aware that the UE will not retransmit and can accordingly reassign those resources. In some instances, the eNB and the UE may agree on a timeline in which the retransmission is sent in the next onDuration.

Various aspects include eNB behavior that is different than in conventional LTE. For instance, when the eNB receives a request from the UE to configure DRX settings, the eNB can grant the request automatically or after discerning that the UE is in a problematic band.

Furthermore, if the UE sends a Scheduling Request (SR) in the onDuration, the eNB can be configured to provide uplink and downlink grants in the same onDuration. In conventional LTE, there is no deadline for an eNB to send grants in response to a scheduling request. Thus, various aspects respect the DRX cycle by providing grants within the same onDuration.

Additionally, in some instances, it may not be possible or desirable to set the drx-InactivityTimer and drx-RestransmissionTimer parameters to zero. In such cases, the drx-InactivityTimer and drx-RestransmissionTimer parameters can be set to a small value, such as one. However, in conventional LTE, if the drx-InactivityTimer and drx-RestransmissionTimer parameters are non-zero, then it is possible for the eNB to keep the UE awake throughout the entire DRX cycle. Thus, various aspects change the behavior of the eNB. In one example, a request by the UE to set either or both of the drx-InactivityTimer and drx-RestransmissionTimer parameters to one is an indication that the UE has a coexistence situation. Also, when such parameters are set to one, the eNB can be configured not to give any downlink grants or retransmissions past the onDuration.

If the maxHARQTx parameter is set to one on the uplink, then the eNB can be configured not to give new uplink grants past the onDuration. If the maxHARQTx parameter is not set to one, then the eNB can be configured not to give new uplink grants in the last four subframes of onDuration and beyond. Thus, if a NACK is received after onDuration, no retransmission is made.

In other aspects, behavior of the UE is changed. For instance, the UE may send a request to the eNB for DRX parameters that facilitate a TDM solution to a coexistence issue.

Also, the UE can be configured to refrain from sending a SR or a PRACH, even if data is pending during the inactive period of the DRX cycle. Instead, the UE can delay sending the SR or PRACH until the next onDuration. By contrast, in conventional LTE, the UE will typically send an SR or a PRACH within a short time period when data is pending.

In another example, the UE can be configured so that it requests a drxStartOffset parameter that coincides with a SR opportunity. In response, the eNB configures the onDuration to start with an SR opportunity. Thus, the UE does not have to wait to send the SR.

If the above-described changes are not made to conventional LTE, then some updates can be made to approximate the behavior described above. For instance, in a scenario when a UE is compelled to retransmit past the onDuration, rather than simply retransmitting, the CxM within the UE can arbitrate among the various radios to find a solution (e.g., to delay the retransmission until the next onDuration period). Also, a UE can be configured with a CxM that can deny a transmission if the transmission runs afoul of a coexistence parameter.

Returning toFIG. 10, it is noted that a UE may request a DRX configuration in much the same way that a UE may request a measurement gap configuration. Also, the eNB behavior may be similar to that shown inFIG. 10.

Specifically, a new reconfiguration request message1001may be added to an LTE communication system and is sent from a UE1003to an eNB1005to initiate a configuration or reconfiguration of a DRX cycle. A reconfiguration request message1001is sent to the eNB1005to initiate a DRX cycle configuration, and the message1001can include a reason for the request (e.g., Bluetooth ON), a range of requested parameters (e.g., indications of one or more requested values for drx-InactivityTimer, drx-RestransmissionTimer, and the like), and/or any other useful information. The eNB then either grants or denies the request, as shown in scenarios1010and1020, respectively. Also, when an RRC connection is not already in place, a connection request message (not shown) can include much of the information discussed above (e.g., requested parameters, a reason for the request, etc.). The eNB uses the information in the connection request message to know that a coexistence issue exists and to assign a configuration to the UE to reduce or minimize coexistence issues when LTE activity is initiated.

FIG. 13illustrates a methodology1300that facilitates implementation of multi-radio coexistence functionality within a wireless communication system. At block1302, one or more sets of resources for which coexistence issues are present are identified. In any of the methodologies shown inFIGS. 13-17, the identification recognizes that unacceptable performance occurs or is expected to occur due to interference. In one example, a device with multiple radios is equipped to detect interference. Additionally or alternatively, the device may be programmed to know that when certain radios use certain channels, coexistence issues are necessarily present. Additionally or alternatively, the device may be programmed to know that certain radios operating at the same time will necessarily have coexistence issues. Coexistence issues may be identified, e.g., by the CxM640ofFIG. 6. At block1304, a message is submitted to a base station that affects reconfiguration of a timing schedule of a first one of the radios to provide for periods of inactivity of the first one of the radios. The inactivity periods providing operating periods for at least a second one of the radios.

FIG. 14illustrates a methodology1400that facilitates implementation of multi-radio coexistence functionality within a wireless communication system. At block1402, a coexistence indication message is received from a user equipment (UE) having multiple radios. The coexistence indication message indicates a coexistence issue for at least one of the radios of the UE. At block1404, periods of inactivity are provided for at least one of the radios of the UE, associated with the coexistence issue, in response to receiving the coexistence indication message.

FIG. 15illustrates a methodology1500that facilitates implementation of multi-radio coexistence functionality within a wireless communication system. At block1502, a DRX timeline associated with communication with an eNB is identified. At block1504, transmissions to the eNB are managed such that transmissions to the eNB beyond a predefined threshold on the DRX timeline are substantially prevented.

FIG. 16illustrates a methodology1600that facilitates implementation of multi-radio coexistence functionality within a wireless communication system. At block1602, a measurement gap pattern associated with communication with an eNB is identified. At block1604, transmissions to the eNB are managed such that the transmissions to the eNB conform to the measurement gap pattern.

FIG. 17illustrates a methodology1700that facilitates implementation of multi-radio coexistence functionality within a wireless communication system. At block1702, a parameter request message and/or a handover request message is received from a served UE. At block1704, a set of resources utilized by the served UE is identified. At block1706, at least one parameter request or handover request received from the served UE is granted upon determining that the set of resources utilized by the served UE is associated with a coexistence issue.

The examples above describe aspects implemented in an LTE system. However, the scope of the disclosure is not so limited. Various aspects may be adapted for use with other communication systems, such as those that employ any of a variety of communication protocols including, but not limited to, CDMA systems, TDMA systems, FDMA systems, and OFDMA systems.