WO2018073812A1 - Schéma de sauts de fréquence pour l'extension de couverture - Google Patents

Schéma de sauts de fréquence pour l'extension de couverture Download PDF

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Publication number
WO2018073812A1
WO2018073812A1 PCT/IB2017/056553 IB2017056553W WO2018073812A1 WO 2018073812 A1 WO2018073812 A1 WO 2018073812A1 IB 2017056553 W IB2017056553 W IB 2017056553W WO 2018073812 A1 WO2018073812 A1 WO 2018073812A1
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Prior art keywords
frequency
hopping sequence
wireless device
sequence
step size
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PCT/IB2017/056553
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English (en)
Inventor
Oskar Drugge
Peter Alriksson
Jung-Fu Cheng
David Sugirtharaj
Emma Wittenmark
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Telefonaktiebolaget L M Ericsson (Publ)
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Publication of WO2018073812A1 publication Critical patent/WO2018073812A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/713—Spread spectrum techniques using frequency hopping
    • H04B1/7143—Arrangements for generation of hop patterns

Definitions

  • the disclosed subject matter relates generally to telecommunications. Certain embodiments relate more particularly to concepts such as unlicensed spectrum, frequency hopping, LTE-Unlicensed (LTE-U), coverage extension, enhanced Machine Type
  • LAA Long Term Evolution
  • LTE Long Term Evolution
  • Candidate bands for LTE operation in the unlicensed spectrum include 5 GHz, 3.5 GHz, among others.
  • the unlicensed spectrum can be used as a complement to the licensed spectrum, but also allows completely standalone operation.
  • the CA framework allows a device to aggregate two or more carriers, with the condition that at least one carrier (or frequency channel) is in the licensed spectrum and at least one carrier is in the unlicensed spectrum. In the standalone (or completely unlicensed spectrum) mode of operation, one or more carriers are selected solely in the unlicensed spectrum.
  • LBT listen-before-talk
  • Wi-Fi Wireless Local Area Network
  • LTE uses OFDM in the downlink (DL) and Discrete Fourier Transform (DFT)- spread Orthogonal Frequency Division Multiplexing (OFDM) (also referred to as Single- Carrier Frequency Division Multiple Access (SC-FDMA)) in the UL.
  • DFT Discrete Fourier Transform
  • OFDM Orthogonal Frequency Division Multiplexing
  • SC-FDMA Single- Carrier Frequency Division Multiple Access
  • FIG. 1 illustrates an example LTE DL physical resource.
  • the basic LTE DL physical resource can be seen as a time-frequency grid where each resource element corresponds to one OFDM subcarrier during one OFDM symbol interval.
  • the UL subframe has the same subcarrier spacing as the DL and the same number of SC-FDMA symbols in the time domain as OFDM symbols in the DL.
  • FIG. 2 illustrates an example of the LTE time-domain structure.
  • LTE DL transmissions are organized into radio frames of 10 ms.
  • Each subframe comprises two slots of duration 0.5 ms each, and the slot numbering within a frame ranges from 0 to 19.
  • one subframe consists of 14 OFDM symbols. The duration of each symbol is approximately 71.4 ⁇ .
  • resource allocation in LTE is typically described in terms of resource blocks, where a resource block corresponds to one slot (0.5 ms) in the time domain and 12 contiguous subcarriers in the frequency domain.
  • a pair of two adjacent resource blocks in the time direction i.e., 1.0 ms
  • Resource blocks are numbered in the frequency domain, starting with 0 from one end of the system bandwidth.
  • DL transmissions are dynamically scheduled (i.e., in each subframe the base station transmits control information about which terminals data is transmitted to and upon which resource blocks the data is transmitted, in the current DL subframe).
  • CFI Control Format Indicator
  • the DL subframe also contains common reference symbols, which are known to the receiver and used for coherent demodulation of, for example, the control information.
  • the reference symbols shown in FIG. 3 are the cell-specific reference symbols (CRS) and are used to support multiple functions, including fine-time and frequency synchronization and channel estimation for certain transmission modes.
  • CRS cell-specific reference symbols
  • UL transmissions are dynamically scheduled (i.e., in each DL subframe the base station transmits control information about which terminals should transmit data to the eNB in subsequent subframes, and upon which resource blocks the data is transmitted).
  • the UL resource grid is comprised of data and UL control information in the Physical Uplink Shared Channel (PUSCH), UL control information in the Physical Uplink Control Channel (PUCCH), and various reference signals such as demodulation reference signals (DMRS) and sounding reference signals (SRS).
  • PUSCH Physical Uplink Shared Channel
  • PUCCH Physical Uplink Control Channel
  • DMRS demodulation reference signals
  • SRS sounding reference signals
  • FIG. 4 illustrates an example UL subframe. Note that UL DMRS and SRS are time- multiplexed into the UL subframe, and SRS are always transmitted in the last symbol of a normal UL subframe.
  • the PUSCH DMRS is transmitted once every slot for subframes with normal cyclic prefix, and is located in the fourth and eleventh SC-FDMA symbols.
  • DL or UL resource assignments can also be scheduled on the enhanced Physical Downlink Control Channel (EPDCCH).
  • EPCCH Physical Downlink Control Channel
  • UE user equipment
  • DCI Downlink Control Information
  • CRC Cyclic Redundancy Check
  • C-RNTI Cell Radio Network Temporary Identifier
  • a unique C-RNTI is assigned by a cell to every UE associated with it, and can take values in the range 0001-FFF3 in hexadecimal format.
  • a UE uses the same C-RNTI on all serving cells.
  • the LTE Rel. 10 standard supports bandwidths larger than 20 MHz.
  • One requirement on LTE Rel. 10 is to assure backward compatibility with LTE Rel. 8. This should also include spectrum compatibility. That would imply that an LTE Rel. 10 carrier, wider than 20 MHz, should appear as a number of LTE carriers to an LTE Rel. 8 terminal. Each such carrier can be referred to as a Component Carrier (CC).
  • CC Component Carrier
  • CA implies that an LTE Rel. 10 terminal can receive multiple CCs, where the CCs have, or at least the possibility to have, the same structure as a Rel. 8 carrier.
  • FIG. 5 illustrates an example of carrier aggregation.
  • a CA -capable UE is assigned a primary cell (PCell) which is always activated, and one or more secondary cells (SCells) which may be activated or deactivated dynamically.
  • PCell primary cell
  • SCells secondary cells
  • the number of aggregated CCs as well as the bandwidth of the individual CC may be different for UL and DL.
  • a symmetric configuration refers to the case where the number of CCs in DL and UL is the same, whereas an asymmetric configuration refers to the case where the number of CCs in DL and UL is different.
  • the number of CCs configured in a cell may be different from the number of CCs seen by a terminal.
  • a terminal may, for example, support more DL CCs than UL CCs, even though the cell is configured with the same number of UL and DL CCs.
  • a feature of CA is the ability to perform cross-carrier scheduling. This mechanism allows a (E)PDCCH on one CC to schedule data transmissions on another CC by means of a 3 -bit Carrier Indicator Field (CIF) inserted at the beginning of the
  • (E)PDCCH messages For data transmissions on a given CC, a UE expects to receive scheduling messages on the (E)PDCCH on just one CC— either the same CC, or a different CC via cross-carrier scheduling.
  • This mapping from (E)PDCCH to PDSCH is also configured semi-statically.
  • IoT Internet-Of-Things
  • Current 3GPP -based standards offer three different variants supporting IoT services: enhanced Machine-Type Communication (eMTC), Narrowband IoT (NB-IoT) and Extended Coverage Global Systems for Mobile Communications (EC-GSM).
  • eMTC and NB-IoT have been designed using LTE as a baseline, with the main difference between the two being the minimum occupied bandwidth.
  • eMTC and NB-IoT use 1.4 MHz and 180 kHz minimum bandwidth, respectively.
  • 3GPP LTE Rel. 12 defined a UE power saving mode allowing long battery lifetime and a new UE category allowing reduced modem complexity.
  • 3GPP Rel. 13 further introduced the eMTC feature, with a new UE category, Cat-M, that further reduces UE cost while supporting coverage enhancement.
  • One element to enable cost reduction for Cat-M UE is to introduce a reduced UE bandwidth of 1.4 MHz in DL and UL within any system bandwidth (as described in 3GPP TR 36.888 vl2.0.0, "Study on provision of low-cost Machine-Type Communications (MTC) User Equipments (UEs) based on LTE (Rel. 12)" (hereinafter "TR 36.888”)).
  • the system bandwidth can be up to 20 MHz. This total bandwidth is divided into physical resource blocks (PRBs) of 180 kHz. Cat-M UEs with reduced UE bandwidth of 1.4 MHz only receive a part of the total system bandwidth at a time— a part corresponding to up to 6 PRBs.
  • PRB group a group of 6 PRBs is referred to as a "PRB group.”
  • time repetition techniques are used to allow energy accumulation of the received signals at the UE side.
  • physical data channels e.g., PDSCH, PUSCH
  • subframe bundling also known as transmission time interval (TTI) bundling
  • TTI transmission time interval
  • HARQ Hybrid Automatic Repeat Request
  • HARQ Hybrid Automatic Repeat Request
  • Energy accumulation of the received signals involves several aspects.
  • One of the main aspects involves accumulating energy for reference signals, for example by applying time-filters, in order to increase the quality of channel estimates used in the demodulation process.
  • Another main aspect involves accumulation of demodulated soft-bits across repeated transmissions.
  • Unlicensed bands offer the possibility for deployment of radio networks by non- traditional operators that do not have access to licensed spectrum, such as building owners, industrial site and municipalities who want to offer a service within the operation they control.
  • the LTE standard has been evolved to operate in unlicensed bands for the sake of providing mobile broadband using unlicensed spectrum.
  • the 3GPP-based feature of LAA was introduced in Rel. 13, supporting CA between a primary carrier in licensed bands, and one or several secondary carriers in unlicensed bands. Further evolution of the LAA feature, which only supports DL traffic, was specified within the Rel. 14 feature of enhanced Licensed Assisted Access feLAA), which added the possibility to also schedule UL traffic on the secondary carriers.
  • MFA MulteFire Alliance
  • work within the MulteFire Alliance (MFA) aimed to standardize a system that would allow the use of standalone primary carriers within unlicensed spectrum.
  • the resulting MulteFire 1.0 standard supports both UL and DL traffic.
  • ETSI European Telecommunications Standards Institute
  • ETSI EN 300 328 Harmonized Standard covering the essential requirements of E Directive 2014/53/EU
  • ETSI EN 300 328 provisions include several adaptivity requirements for different operation modes. From the top level, equipment can be classified either as frequency hopping or non-frequency hopping, as well as adaptive or non-adaptive. Adaptive equipment is mandated to sense whether the channel is occupied in order to better coexist with other users of the channel. The improved coexistence may come from, for example, LBT or detect and avoid (DAA) mechanisms. Non -frequency hopping equipment are subject to requirements on maximum power spectral density (PSD) of 10 dBm/MHz, which limits the maximum output power for systems using narrower bandwidths. Common for any of the adaptive schemes is the consequence that the receiving node will be unaware of the result of the sensing, and thus needs to detect whether signal is present or not. While such a signal detection most likely would be feasible for devices operating with moderate to high Signal to Interference plus Noise Ratios (SINR) levels, they may be infeasible for very low SINR levels.
  • SINR Signal to Interference plus Noise Ratios
  • the received SINR of each individual transmission is very low.
  • the effective SINR increases.
  • the repetition techniques may fail.
  • One way of avoiding this would be to attempt detection of each individual repetition, although as already described this may not be feasible at the very low SINR levels targeted with these IoT standards.
  • An IoT standard for 2.4 GHz in Europe may therefore be best devised by categorizing its devices as non-adaptive frequency hopping.
  • Requirements for non-adaptive frequency hopping include e.g. the following. First, a maximum on -time of 5 ms, which is required to be followed by a transmission gap. Second, a minimum duration of the transmission gap of 5 ms. Third, a maximum accumulated transmit time of 15 ms, which is the maximum total transmission time a node may be allowed to use before moving to the next frequency hop.
  • a method in a wireless communication network comprises determining a frequency hopping sequence for communication between a wireless device and a network node, the frequency hopping sequence being a function of a first hopping sequence and a second hopping sequence, wherein the first hopping sequence has a first frequency step size and a first sequence length, the second hopping sequence has a second frequency step size and a second sequence length, and the first frequency step size is greater than the second frequency step size, and communicating on frequencies selected according to the determined frequency hopping sequence.
  • the method can be performed by e.g. the wireless device and/or the network node.
  • the first frequency step size is greater than or equal to a frequency range covered by the second hopping sequence.
  • the first frequency step size is less than a frequency range covered by the second hopping sequence.
  • the hopping sequence is defined according to
  • nk,l m k ' $ + s k,l
  • k represents a hop index of the first hopping sequence
  • / represents a hop index of the second hopping sequence
  • n k l l represents an z ' -th instance of a (k,l)-t frequency of the hopping sequence
  • m k l represents an i-th instance of a k-th element of the first hopping sequence
  • S represents the first frequency step size
  • s k l represents an z ' -th instance of a (k,l)-t element of the second hopping sequence.
  • the frequencies selected according to the determined frequency hopping sequence are disposed in unlicensed spectrum.
  • the method further comprises, at the wireless device, performing channel estimation filtering across multiple frequency hops of the second hopping sequence.
  • performing the channel estimation filtering comprises filtering channel estimates across a time duration that spans the multiple frequency hops of the second hopping sequence.
  • the method further comprises, at the wireless device, determining a difference between a current and previous frequency of the wireless device, and in response to determining that the difference is larger than a first threshold, resetting at least one channel estimation filter.
  • the method further comprises estimating a residual timing error.
  • the method further comprises applying
  • an apparatus for wireless communication comprises at least one processor, memory and transceiver collectively configured to perform a method such as that described above.
  • the apparatus may be e.g. a wireless device or a network node.
  • FIG. 1 illustrates an example LTE DL physical resource.
  • FIG. 2 illustrates an example of the LTE time-domain structure.
  • FIG. 3 illustrates an example DL subframe
  • FIG. 4 illustrates an example UL subframe.
  • FIG. 5 illustrates an example of carrier aggregation.
  • FIG. 6 illustrates an exemplary wireless communications network, in accordance with certain embodiments.
  • FIG. 7 illustrates an example of operating eMTC with UL and DL on the same channel, in accordance with certain embodiments.
  • FIG. 8 illustrates an example of operating eMTC with UL and DL on a pair of frequency channels, in accordance with certain embodiments.
  • FIG. 9 illustrates an example of transmission and frequency hopping sequence, in accordance with certain embodiments.
  • FIG. 10 illustrates a concept for design of frequency hopping sequences involving main and sub-hopping, in accordance with certain embodiments.
  • FIG. 11 illustrates an exemplary hopping sequence according to a hierarchical frequency hopping design, in accordance with certain embodiments.
  • FIG. 14 illustrates an example sub-hopping sequence with an arbitrary start frequency within the sequence of sub-hopping frequencies, in accordance with certain embodiments.
  • FIG. 15 is a flow chart illustrating a method in a wireless device, in accordance with certain embodiments.
  • FIG. 16 is a flow diagram of a method in a network node, in accordance with certain embodiments.
  • FIG. 17 is a flow diagram of a method in a network node, in accordance with certain embodiments.
  • FIG. 18 is a block schematic of an exemplary wireless device, in accordance with certain embodiments.
  • FIG. 19 is a block schematic of an exemplary network node, in accordance with certain embodiments.
  • FIG. 20 is a block schematic of an exemplary radio network controller or core network node, in accordance with certain embodiments.
  • FIG. 21 is a block schematic of an exemplary wireless device, in accordance with certain embodiments.
  • FIG. 22 is a block schematic of an exemplary network node, in accordance with certain embodiments.
  • FIG. 23 is a flow diagram of a method in a wireless communication network, in accordance with certain embodiments.
  • channel estimate filtering may be limited because of the requirements on maximum accumulated transmit time, as the receiver may not be able to continue filtering past the point where the transmitter has performed a frequency hop.
  • Certain embodiments of the disclosed subject matter may address the above and other shortcomings. For instance, in some embodiments this is achieved by using a scheme for the definition of frequency hopping sequences that limits a maximum distance in frequency between subsequent frequency hops, thereby enabling receivers to attempt filtering of channel estimates across a time duration that spans more than one frequency hop.
  • Such embodiments may assume that the underlying channel has a large enough coherence bandwidth such that the channel estimate on two adjacent frequencies is similar enough.
  • the idea is thus two-fold: the first part pertains to the design of hopping sequences of the system, while the second part targets the UE behavior (i.e., methods to realize filtering of channel estimates across multiple frequency hops).
  • the various embodiments described herein enable design of frequency hopping patterns that comply with spectrum regulations while simultaneously enabling UEs to improve their reception quality by employing filtering of estimates needed in the demodulation process across a time-period that spans multiple frequency hops.
  • a method in a network node determines a first hopping sequence where a difference in the corresponding frequency between two consecutive values is smaller than a first value.
  • the network node determines a second hopping sequence.
  • the difference in the corresponding frequency between two consecutive values for the second hopping sequence may be larger than the frequency range covered by the first hopping sequence.
  • the difference in the corresponding frequency between two consecutive values for the second hopping sequence may be smaller than the frequency range covered by the first hopping sequence.
  • the network node operates on a frequency corresponding to a function of the first and second hopping sequences. The above steps may advantageously aid channel estimation in a wireless device.
  • a method in a wireless device for performing channel estimation in a frequency hopping scheme determines a difference between a current frequency and a previous frequency the wireless device was operating on. The wireless device determines whether the difference between the current frequency and the previous frequency is larger than a first channel, and determines whether channel conditions require a reset. Upon determining either that the frequency difference is larger than the first threshold or that the channel conditions require a reset, the wireless device resets one or more channel estimation filters. In certain embodiments, the wireless device may apply a compensation for residual timing errors. The wireless device performs channel estimation filtering. In certain embodiments, the wireless device may estimate a residual timing error. The wireless device changes frequency according to a hopping pattern of the frequency hopping system.
  • Certain embodiments of the disclosed subject matter may provide one or more technical advantages.
  • the combination of the various embodiments described herein and existing repetition techniques such as those introduced in, for example, the eMTC or NB-IoT standards, may advantageously enable a new IoT standard to operate at very low received SINR levels, even when frequency hopping is required. This in turn could increase coverage and allow for a lower density in the network deployment, ultimately reducing the deployment and operational cost.
  • certain embodiments may advantageously aid channel estimation in a wireless device.
  • Other advantages may be readily apparent to one having skill in the art.
  • embodiments may have none, some, or all of the recited advantages.
  • FIG. 6 is a block diagram illustrating an embodiment of a network 100, in accordance with certain embodiments.
  • Network 100 includes one or more UE(s) 110 (which may be interchangeably referred to as wireless devices 110) and one or more network node(s) 115 (which may be interchangeably referred to as eNBs 115).
  • UEs 110 may communicate with network nodes 115 over a wireless interface.
  • a UE 110 may transmit wireless signals to one or more of network nodes 115, and/or receive wireless signals from one or more of network nodes 115.
  • the wireless signals may contain voice traffic, data traffic, control signals, and/or any other suitable information.
  • an area of wireless signal coverage associated with a network node 115 may be referred to as a cell 125.
  • UEs 110 may have device-to-device (D2D) capability. Thus, UEs 110 may be able to receive signals from and/or transmit signals directly to another UE.
  • D2D device-to-device
  • network nodes 115 may interface with a radio network controller.
  • the radio network controller may control network nodes 115 and may provide certain radio resource management functions, mobility management functions, and/or other suitable functions. In certain embodiments, the functions of the radio network controller may be included in network node 115.
  • the radio network controller may interface with a core network node. In certain embodiments, the radio network controller may interface with the core network node via an interconnecting network 120.
  • Interconnecting network 120 may refer to any interconnecting system capable of transmitting audio, video, signals, data, messages, or any combination of the preceding.
  • Interconnecting network 120 may include all or a portion of a public switched telephone network (PSTN), a public or private data network, a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a local, regional, or global communication or computer network such as the Internet, a wireline or wireless network, an enterprise intranet, or any other suitable communication link, including combinations thereof.
  • PSTN public switched telephone network
  • LAN local area network
  • MAN metropolitan area network
  • WAN wide area network
  • Internet local, regional, or global communication or computer network
  • wireline or wireless network such as the Internet
  • enterprise intranet an enterprise intranet, or any other suitable communication link, including combinations thereof.
  • the core network node may manage the establishment of communication sessions and various other functionalities for UEs 110.
  • UEs 110 may exchange certain signals with the core network node using the non-access stratum layer.
  • signals between UEs 110 and the core network node may be transparently passed through the radio access network.
  • network nodes 115 may interface with one or more network nodes over an internode interface, such as, for example, an X2 interface.
  • example embodiments of network 100 may include one or more wireless devices 110, and one or more different types of network nodes capable of communicating (directly or indirectly) with wireless devices 110.
  • UEs 110 described herein can be any type of wireless device capable of communicating with network nodes 115 or another UE over radio signals.
  • UE 110 may also be a radio communication device, target device, D2D UE, machine-type-communication UE or UE capable of machine to machine communication (M2M), low-cost and/or low-complexity UE, a sensor equipped with UE, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), etc.
  • UE 110 may operate under either normal coverage or enhanced coverage with respect to its serving cell.
  • the enhanced coverage may be interchangeably referred to as extended coverage.
  • UE 110 may also operate in a plurality of coverage levels (e.g., normal coverage, enhanced coverage level 1, enhanced coverage level 2, enhanced coverage level 3 and so on). In some cases, UE 110 may also operate in out-of-coverage scenarios.
  • radio network node (or simply “network node”) is used. It can be any kind of network node, which may comprise a base station (BS), radio base station, Node B, base station (BS), multi-standard radio (MSR) radio node such as MSR BS, evolved Node B (eNB), network controller, radio network controller (RNC), base station controller (BSC), relay node, relay donor node controlling relay, base transceiver station (BTS), access point (AP), radio access point, transmission points, transmission nodes, Remote Radio Unit (RRU), Remote Radio Head (RRH), nodes in distributed antenna system (DAS), Multi-cell/multicast Coordination Entity (MCE), core network node (e.g., MSC, MME, etc.), O&M, OSS, SON, positioning node (e.g., E-SMLC), MDT, or any other suitable network node.
  • BS base station
  • MSR multi-standard radio
  • eNB evolved Node B
  • RNC radio network controller
  • network node and UE should be considered non-limiting and does in particular not imply a certain hierarchical relation between the two; in general "eNodeB” could be considered as device 1 and “UE” device 2, and these two devices communicate with each other over some radio channel.
  • eNodeB could be considered as device 1 and "UE” device 2
  • Example embodiments of UE 110, network nodes 115, and other network nodes are described in more detail below with respect to FIG. S 18-22.
  • FIG. 6 illustrates a particular arrangement of network 100
  • network 100 may include any suitable number of UEs 110 and network nodes 115, as well as any additional elements suitable to support communication between UEs or between a UE and another communication device (such as a landline telephone).
  • LTE Long Term Evolution
  • the embodiments may be implemented in any appropriate type of telecommunication system supporting any suitable communication standards (including 5G standards) and using any suitable components, and are applicable to any radio access technology (RAT) or multi-RAT systems in which a UE receives and/or transmits signals (e.g., data).
  • RAT radio access technology
  • multi-RAT multi-RAT
  • the various embodiments described herein may be applicable to LTE, LTE-Advanced, 5G, UMTS, HSPA, GSM, cdma2000, WCDMA, WiMax, UMB, WiFi, another suitable radio access technology, or any suitable combination of one or more radio access technologies.
  • LTE Long Term Evolution
  • 5G Fifth Generation
  • UMTS Fifth Generation
  • HSPA High Speed Packet Access
  • GSM Global System for Mobile communications
  • cdma2000 High Speed Downlink Packet Access
  • WCDMA Wideband Code Division Multiple Access
  • WiMax Worldwide Interoperability for Microwave Access
  • the various embodiments described herein may advantageously enable the creation of frequency hopping patterns in a system operating in unlicensed bands. Certain embodiments may enable design of frequency hopping patterns that comply with spectrum regulations while simultaneously enabling UEs to improve their reception quality by employing filtering of estimates needed in the demodulation process across a time-period that spans multiple frequency hops.
  • the transmitter and receiver hops synchronously according to a pre-determined pattern that has been made known to both transmitter and receiver.
  • the actual sequence used could, for example, be signaled as part of the initial attachment sequence, or implicitly derived based on a function that depends on, for example, a transmitter ID, which in turn could be determined during an initial attachment procedure to the network or node.
  • Different groups of devices may use different frequency hopping sequences, allowing re-use of the spectrum.
  • FIG. 7 illustrates an example of operating eMTC with UL and DL on the same channel, in accordance with certain embodiments.
  • a first mode of operating eMTC UL and DL on the same frequency channel an exemplary design of the operating channels is illustrated in FIG. 7.
  • FIG. 8 illustrates an example of operating eMTC with UL and DL on a pair of frequency channels, in accordance with certain embodiments.
  • a second mode of operating eMTC UL and DL on a pair of frequency channels an exemplary design of the operating channels is illustrated in FIG. 8.
  • FIG. 9 illustrates an example of transmission and frequency hopping sequence, in accordance with certain embodiments. Based on the requirements listed in Section 1.4 above (describing 2.4 GHz requirements for the European region and coverage extension), a pattern as shown in FIG. 9 could be devised that attempts to concentrate the DL signal as much as possible, while maximizing the time spent on each frequency hop, the dwell time.
  • the example of FIG. 7 is a transmission and frequency hopping sequence that would be compliant with the non-adaptive frequency hopping option of ETSI EN 300 328.
  • a first example embodiment involves frequency hopping sequences based on a hierarchical design as shown in FIG. 10.
  • FIG. 10 illustrates a concept for design of frequency hopping sequences involving main and sub-hopping, in accordance with certain embodiments.
  • the frequency hopping sequence is further based on a main hopping sequence and a sub- hopping sequence.
  • the main hopping sequence is designed to enable large frequency separation between hops.
  • the main hopping sequence serves to randomize interference.
  • the sub-hopping sequence is within each main hop. Within the sub-hopping sequence the frequency distance between two intermediate sub-hops is limited.
  • the sub-hopping sequence serves the purpose of letting the UE filter channel estimates across multiple frequency hops, to enhance reception performance.
  • FIG. 11 illustrates an exemplary hopping sequence according to a hierarchical frequency hopping design, in accordance with certain embodiments. From the non-limiting exemplary embodiment illustrated in FIG. 11, it can be observed that the frequency separations between hops within a main hop duration are limited. This enables better channel estimation performance at the receiver. Between the main hops, large frequency separations are used to enable better interference randomization.
  • n k l l n k l l , where:
  • k denotes main hop index, ranging from 0 to T- 1.
  • K 7.
  • the hopping sequence is calculated by the following equation (1):
  • • s k l is a sub-hopping sequence of length L.
  • the sequence m k ' cm be defined as a pseudo-random sequence. In some embodiments, the sequence has the property that no value within the value range
  • cell ID and network ID are used to initialize a pseudo-random sequence generator.
  • the set of sequences m k ' are defined and standardized, and the selection of a specific sequence to use for transmission and reception is selected using a function that translates a physical cell ID (PCI) and a network ID to an index i within the set of sequences.
  • the specific sequence to use m k ' is the direct result of a formula that takes physical cell ID (PCI) and a network ID as input and outputs a hopping sequence.
  • the frequency step size for main hopping sequence S is set to a value smaller than the length of the sub-hopping sequence. That is, S ⁇ L.
  • the frequency channel indices visited by a frequency hopping sequence n k l l may have repeated values. This design allows for longer main hopping sequences. That is, K can be larger.
  • the sequence s k l l can be defined as a pseudo-random sequence.
  • the sequence has the property that no value within the value range is occurring more than once.
  • cell ID, network ID and the main hop index k are used to initialize a pseudo-random sequence generator.
  • the set of sequences s k l are defined and standardized, and the selection of a specific sequence to use for transmission and reception is selected using a function that translates a physical cell ID (PCI), a network ID and the main hop index k to an index i within the set of sequences.
  • the specific sequence to use s k l l is the direct result of a formula that takes physical cell ID (PCI), a network ID and the main hop index k as input and outputs a hopping sequence.
  • the set of sequences s k l are not dependent of the main hop index k. That is, for frequency hopping sequence n k l the same s sequence is used across all main hops:
  • n k l ,i m k l - S + s ⁇
  • the s ⁇ sequence can be determined based on physical cell ID (PCI), a network ID as described above.
  • PCI physical cell ID
  • the set of sequences s k l are dependent on only the main hop index k. That is, for different frequency hopping sequence n k l the same s k x sequence is used:
  • nk,l m k ' S + s k,l
  • the s k l sequence can be determined based on the main hop index k as described above. [0102] According to still another example embodiment, the same s ( sequence is used for all such hierarchically designed frequency hopping sequences:
  • n k l ,i m k l - S + s l
  • the sub-hopping sequence cycles through the index with an offset of 2 two indexes per hop. For example:
  • FIG. 14 illustrates an example sub-hopping sequence with an arbitrary start frequency within the sequence of sub-hopping frequencies, in accordance with certain embodiments.
  • the sub- hopping sequence s ( could be extended in a way that differs depending on the hopping sequence index and/or main hop index, k :
  • o k l is an offset that is determined by for frequency hopping sequence index ⁇ and/or the main hop index k.
  • FIG. 15 is a flow chart illustrating a method in a wireless device, in accordance with certain embodiments.
  • the wireless device for example, UE 1 10 described above in relation to FIG. 6
  • the wireless device can thus determine whether or not the current operating frequency is associated with the first sub-hop within a main hop.
  • step 1502 determines that the current operating frequency is the first sub-hop within a main hop
  • the method proceeds to step 1504, where the wireless device resets certain filters used in algorithms related to the demodulation process.
  • a non- limiting example of such a filter would be the filtering of channel estimates.
  • step 1502 the wireless device determines that the current frequency is not associated with the first subhop of a main hop, the method proceeds to step 1506 where the wireless device makes an assessment of the channel conditions.
  • the assessment of channel conditions may include, but is not limited to, one or more of Doppler estimation, RMS delay spread estimation and SINR estimation.
  • the method proceeds to step 1504, where the wireless device resets the filters.
  • the wireless device may apply a compensation related to a residual timing error. Regardless of whether the wireless device applies a compensation related to the residual timing error, the method proceeds to step 1510.
  • step 1510 the wireless device performs filtering.
  • the method proceeds to step 1512, where the wireless device may estimate a residual timing error. Regardless of whether the wireless device estimates residual timing error at step 1512, the method proceeds to step 1514, where the wireless device changes the frequency to the next frequency in the hopping sequence. The method then returns to step 1502, where the wireless device repeats the process described above.
  • the various embodiments described herein may advantageously enable the creation frequency hopping patterns in a system operating in unlicensed bands.
  • the various embodiments described herein enable design of frequency hopping patterns that comply with spectrum regulations while simultaneously enabling wireless devices to improve their reception quality by employing filtering of estimates needed in the demodulation process across a time-period that spans multiple frequency hops.
  • FIG. 16 is a flow diagram of a method in a network node, in accordance with certain embodiments. The method begins at step 1604, where the network node determines a first hopping sequence where a difference in the corresponding frequency between two consecutive values is smaller than a first value.
  • the network node determines a second hopping sequence.
  • a difference in the corresponding frequency between two consecutive values may be larger than a frequency range covered by the first hopping sequence.
  • a difference in the corresponding frequency between two consecutive values may be smaller than a frequency range covered by the first hopping sequence.
  • the network node operates on a frequency corresponding to a function of the first and second hopping sequences.
  • FIG. 17 is a flow diagram of a method in a wireless device, in accordance with certain embodiments. The method begins at step 1704, where the wireless device determines a difference between a current frequency and a previous frequency the wireless device was operating on.
  • the wireless device determines whether the difference between the current frequency and the previous frequency is larger than a first threshold.
  • the wireless device determines whether channel conditions require a reset.
  • the wireless device upon determining either that the frequency difference is larger than the first threshold or that the channel conditions require a reset, the wireless device resets one or more channel estimation filters.
  • the wireless device may apply a compensation for residual timing errors.
  • the wireless device performs channel estimation filtering.
  • the wireless device may estimate a residual timing error.
  • the wireless device changes frequency according to a hopping pattern.
  • FIG. 18 is a block schematic of an exemplary wireless device, in accordance with certain embodiments.
  • Wireless device 110 may refer to any type of wireless device communicating with a node and/or with another wireless device in a cellular or mobile communication system.
  • Examples of wireless device 110 include a mobile phone, a smart phone, a PDA (Personal Digital Assistant), a portable computer (e.g., laptop, tablet), a sensor, a modem, a machine-type-communication (MTC) device / machine-to-machine (M2M) device, laptop embedded equipment (LEE), laptop mounted equipment (LME), USB dongles, a D2D capable device, or another device that can provide wireless communication.
  • MTC machine-type-communication
  • M2M machine-to-machine
  • LME laptop mounted equipment
  • USB dongles a D2D capable device, or another device that can provide wireless communication.
  • a wireless device 110 may also be referred to as UE, a station (STA), a device, or a terminal in some embodiments.
  • Wireless device 110 includes transceiver 1810, processor 1820, and memory 1830.
  • transceiver 1810 facilitates transmitting wireless signals to and receiving wireless signals from network node 115 (e.g., via antenna 1840)
  • processor 1820 executes instructions to provide some or all of the functionality described above as being provided by wireless device 110
  • memory 1830 stores the instructions executed by processor 1820.
  • Processor 1820 may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or all of the described functions of wireless device 110, such as the functions of wireless device 110 described above in relation to FIG.S 1-17.
  • processor 1820 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs) and/or other logic.
  • CPUs central processing units
  • microprocessors one or more applications
  • ASICs application specific integrated circuits
  • FPGAs field programmable gate arrays
  • Memory 1830 is generally operable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and/or other instructions capable of being executed by a processor.
  • Examples of memory 1830 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or or any other volatile or non-volatile, non-transitory computer-readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by processor 1020.
  • RAM Random Access Memory
  • ROM Read Only Memory
  • mass storage media for example, a hard disk
  • removable storage media for example, a Compact Disk (CD) or a Digital Video Disk (DVD)
  • CD Compact Disk
  • DVD Digital Video Disk
  • wireless device 110 may include additional components beyond those shown in FIG. 18 that may be responsible for providing certain aspects of the wireless device's functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the solution described above).
  • wireless device 110 may include input devices and circuits, output devices, and one or more synchronization units or circuits, which may be part of the processor 1820.
  • Input devices include mechanisms for entry of data into wireless device 110.
  • input devices may include input mechanisms, such as a microphone, input elements, a display, etc.
  • Output devices may include mechanisms for outputting data in audio, video and/or hard copy format.
  • output devices may include a speaker, a display, etc.
  • FIG. 19 is a block schematic of an exemplary network node, in accordance with certain embodiments.
  • Network node 115 may be any type of radio network node or any network node that communicates with a UE and/or with another network node.
  • network node 115 examples include an eNodeB, a node B, a base station, a wireless access point (e.g., a Wi-Fi access point), a low power node, a base transceiver station (BTS), relay, donor node controlling relay, transmission points, transmission nodes, remote RF unit (RRU), remote radio head (RRH), multi-standard radio (MSR) radio node such as MSR BS, nodes in distributed antenna system (DAS), O&M, OSS, SON, positioning node (e.g., E-SMLC), MDT, or any other suitable network node.
  • Network nodes 115 may be deployed throughout network 100 as a homogenous deployment, heterogeneous deployment, or mixed
  • a homogeneous deployment may generally describe a deployment made up of the same (or similar) type of network nodes 115 and/or similar coverage and cell sizes and inter-site distances.
  • a heterogeneous deployment may generally describe deployments using a variety of types of network nodes 115 having different cell sizes, transmit powers, capacities, and inter-site distances.
  • a heterogeneous deployment may include a plurality of low-power nodes placed throughout a macro-cell layout.
  • Mixed deployments may include a mix of homogenous portions and heterogeneous portions.
  • Network node 115 may include one or more of transceiver 1910, processor 1920, memory 1930, and network interface 1940.
  • transceiver 1910 facilitates transmitting wireless signals to and receiving wireless signals from wireless device 110 (e.g., via antenna 1950)
  • processor 1920 executes instructions to provide some or all of the functionality described above as being provided by a network node 115
  • memory 1930 stores the instructions executed by processor 1920
  • network interface 1940 communicates signals to backend network components, such as a gateway, switch, router, Internet, Public Switched Telephone Network (PSTN), core network nodes or radio network controllers 130, etc.
  • PSTN Public Switched Telephone Network
  • Processor 1920 may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or all of the described functions of network node 115, such as those described above in relation to FIG.S 1-17 above.
  • processor 1920 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, and/or other logic.
  • Memory 1930 is generally operable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and/or other instructions capable of being executed by a processor.
  • Examples of memory 1930 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or or any other volatile or non-volatile, non-transitory computer-readable and/or computer-executable memory devices that store information.
  • RAM Random Access Memory
  • ROM Read Only Memory
  • mass storage media for example, a hard disk
  • removable storage media for example, a Compact Disk (CD) or a Digital Video Disk (DVD)
  • CD Compact Disk
  • DVD Digital Video Disk
  • network interface 1940 is communicatively coupled to processor 1920 and may refer to any suitable device operable to receive input for network node 115, send output from network node 115, perform suitable processing of the input or output or both, communicate to other devices, or any combination of the preceding.
  • Network interface 1940 may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.
  • network node 115 may include additional components beyond those shown in FIG. 19 that may be responsible for providing certain aspects of the radio network node's functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the solutions described above).
  • the various different types of network nodes may include components having the same physical hardware but configured (e.g., via programming) to support different radio access technologies, or may represent partly or entirely different physical components.
  • FIG. 20 is a block schematic of an exemplary radio network controller or core network node 130, in accordance with certain embodiments.
  • network nodes can include a mobile switching center (MSC), a serving GPRS support node (SGSN), a mobility management entity (MME), a radio network controller (RNC), a base station controller (BSC), and so on.
  • the radio network controller or core network node 130 includes processor 2020, memory 2030, and network interface 2040.
  • processor 2020 executes instructions to provide some or all of the functionality described above as being provided by the network node
  • memory 2030 stores the instructions executed by processor 2020
  • network interface 2040 communicates signals to any suitable node, such as a gateway, switch, router, Internet, Public Switched Telephone Network (PSTN), network nodes 115, radio network controllers or core network nodes 130, etc.
  • PSTN Public Switched Telephone Network
  • Processor 2020 may include any suitable combination of hardware and software implemented in one or more modules to execute instructions and manipulate data to perform some or all of the described functions of the radio network controller or core network node 130.
  • processor 2020 may include, for example, one or more computers, one or more central processing units (CPUs), one or more microprocessors, one or more applications, and/or other logic.
  • CPUs central processing units
  • microprocessors one or more applications, and/or other logic.
  • Memory 2030 is generally operable to store instructions, such as a computer program, software, an application including one or more of logic, rules, algorithms, code, tables, etc. and/or other instructions capable of being executed by a processor.
  • Examples of memory 2030 include computer memory (for example, Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (for example, a hard disk), removable storage media (for example, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or or any other volatile or non-volatile, non-transitory computer-readable and/or computer-executable memory devices that store information.
  • RAM Random Access Memory
  • ROM Read Only Memory
  • mass storage media for example, a hard disk
  • removable storage media for example, a Compact Disk (CD) or a Digital Video Disk (DVD)
  • CD Compact Disk
  • DVD Digital Video Disk
  • network interface 2040 is communicatively coupled to processor 2020 and may refer to any suitable device operable to receive input for the network node, send output from the network node, perform suitable processing of the input or output or both, communicate to other devices, or any combination of the preceding.
  • Network interface 2040 may include appropriate hardware (e.g., port, modem, network interface card, etc.) and software, including protocol conversion and data processing capabilities, to communicate through a network.
  • network node may include additional components beyond those shown in FIG. 20 that may be responsible for providing certain aspects of the network node's functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the solution described above).
  • FIG. 21 is a block schematic of an exemplary wireless device, in accordance with certain embodiments.
  • Wireless device 110 may include one or more modules.
  • wireless device 110 may include a determining module 2110, a communication module 2120, a receiving module 2130, an input module 2140, a display module 2150, and any other suitable modules.
  • determining module 2110, communication module 2120, receiving module 2130, input module 2140, display module 2150, or any other suitable module may be implemented using one or more processors, such as processor 1820 described above in relation to FIG. 18.
  • Wireless device 110 may perform the methods related to coverage extension frequency hopping schemes described above with respect to FIG. S 1-17.
  • Determining module 2110 may perform the processing functions of wireless device 110. For example, determining module 2110 may determine a difference between a current frequency and a previous frequency the wireless device was operating on. As another example, determining module 2110 may determine whether the difference between the current frequency and the previous frequency is larger than a first threshold. As still another example, determining module 2110 may determine whether channel conditions require a reset. As yet another example, determining module 2110 may, upon determining either that the frequency difference is larger than the first threshold or that the channel conditions require a reset, reset one or more channel estimation filters. As another example, determining module 2110 may perform channel estimation filtering using the reset one or more channel estimation filters.
  • determining module 2110 may change frequency according to a hopping pattern of the frequency hopping system. As still another example, determining module 2110 may apply a compensation for residual timing errors. As yet another example, determining module 2110 may estimate a residual timing error.
  • Determining module 2110 may include or be included in one or more processors, such as processor 1820 described above in relation to FIG. 18. Determining module 2110 may include analog and/or digital circuitry configured to perform any of the functions of determining module 2110 and/or processor 2120 described above. The functions of determining module 2110 described above may, in certain embodiments, be performed in one or more distinct modules.
  • Communication module 2120 may perform the transmission functions of wireless device 110. Communication module 2120 may transmit messages to one or more of network nodes 115 of network 100. Communication module 2120 may include a transmitter and/or a transceiver, such as transceiver 1810 described above in relation to FIG. 18. Communication module 2120 may include circuitry configured to wirelessly transmit messages and/or signals. In particular embodiments, communication module 2120 may receive messages and/or signals for transmission from determining module 2110. In certain embodiments, the functions of communication module 2120 described above may be performed in one or more distinct modules.
  • Receiving module 2130 may perform the receiving functions of wireless device 110.
  • Receiving module 2130 may include a receiver and/or a transceiver, such as transceiver 1810 described above in relation to FIG. 18.
  • Receiving module 2130 may include circuitry configured to wirelessly receive messages and/or signals.
  • receiving module 2130 may communicate received messages and/or signals to determining module 2110.
  • the functions of receiving module 2130 described above may be performed in one or more distinct modules.
  • Input module 2140 may receive user input intended for wireless device 110.
  • the input module may receive key presses, button presses, touches, swipes, audio signals, video signals, and/or any other appropriate signals.
  • the input module may include one or more keys, buttons, levers, switches, touchscreens, microphones, and/or cameras.
  • the input module may communicate received signals to determining module 2110.
  • Display module 2150 may present signals on a display of wireless device 110.
  • Display module 2150 may include the display and/or any appropriate circuitry and hardware configured to present signals on the display. Display module 2150 may receive signals to present on the display from determining module 2110.
  • Determining module 2110, communication module 2120, receiving module 2130, input module 2140, and display module 2150 may include any suitable configuration of hardware and/or software.
  • Wireless device 110 may include additional modules beyond those shown in FIG. 21 that may be responsible for providing any suitable functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the various solutions described herein).
  • FIG. 22 is a block schematic of an exemplary network node 115, in accordance with certain embodiments.
  • Network node 115 may include one or more modules.
  • network node 115 may include determining module 2210, communication module 2220, receiving module 2230, and any other suitable modules.
  • one or more of determining module 2210, communication module 2220, receiving module 2230, or any other suitable module may be implemented using one or more processors, such as processor 1920 described above in relation to FIG. 19.
  • the functions of two or more of the various modules may be combined into a single module.
  • Network node 115 may perform the methods related to coverage extension frequency hopping schemes described above with respect to FIGS. 1-17.
  • Determining module 2210 may perform the processing functions of network node 115. For example, determining module 2210 may determine a first hopping sequence where a difference in the corresponding frequency between two consecutive values is smaller than a first value. As another example, determining module 2210 may determine a second hopping sequence. As still another example, determining module 2210 may operate on a frequency corresponding to a function of the first and second hopping sequences.
  • Determining module 2210 may include or be included in one or more processors, such as processor 1920 described above in relation to FIG. 19. Determining module 2210 may include analog and/or digital circuitry configured to perform any of the functions of determining module 2210 and/or processor 1920 described above. The functions of determining module 2210 may, in certain embodiments, be performed in one or more distinct modules.
  • Communication module 2220 may perform the transmission functions of network node 115. As one example, communication module 2220 may operate on a frequency corresponding to a function of the first and second hopping sequences. Communication module 2220 may transmit messages to one or more of wireless devices 110.
  • Communication module 2220 may include a transmitter and/or a transceiver, such as transceiver 1910 described above in relation to FIG. 19.
  • Communication module 2220 may include circuitry configured to wirelessly transmit messages and/or signals.
  • communication module 2220 may receive messages and/or signals for transmission from determining module 2210 or any other module.
  • the functions of communication module 2220 may, in certain embodiments, be performed in one or more distinct modules.
  • Receiving module 2230 may perform the receiving functions of network node 115. For example, receiving module 2230 may operate on a frequency corresponding to a function of the first and second hopping sequences. Receiving module 2230 may receive any suitable information from a wireless device. Receiving module 2230 may include a receiver and/or a transceiver, such as transceiver 1910 described above in relation to FIG. 19. Receiving module 2230 may include circuitry configured to wirelessly receive messages and/or signals. In particular embodiments, receiving module 2230 may communicate received messages and/or signals to determining module 2210 or any other suitable module. The functions of receiving module 2230 may, in certain embodiments, be performed in one or more distinct modules.
  • Determining module 2210, communication module 2220, and receiving module 2230 may include any suitable configuration of hardware and/or software.
  • Network node 115 may include additional modules beyond those shown in FIG. 22 that may be responsible for providing any suitable functionality, including any of the functionality described above and/or any additional functionality (including any functionality necessary to support the various solutions described herein).
  • FIG. 23 is a flow diagram of a method 2300 in a wireless communication network, in accordance with certain embodiments. This method could be performed, for instance, by a wireless device and/or network node as described above. The method involves
  • the method comprises determining a frequency hopping sequence for communication between a wireless device and a network node, the frequency hopping sequence being a function of a first hopping sequence and a second hopping sequence, wherein the first hopping sequence has a first frequency step size and a first sequence length, the second hopping sequence has a second frequency step size and a second sequence length, and the first frequency step size is greater than the second frequency step size (S2305), and communicating on frequencies selected according to the determined frequency hopping sequence (S2310).
  • An example of the first hopping sequence is the main hopping sequence described above, which has a relatively large frequency step size such as that between consecutive clusters of dots illustrated FIG.
  • an example of the second hopping sequence is the sub-hopping sequence described above, which has a relatively small frequency step size such as that between consecutive dots illustrated in FIG. 11.
  • the function of the first hopping sequence and the second hopping sequence may be, for instance, a scaled combination of the first and second hopping sequences that repeats over time, as illustrated by equation (1).
  • the first frequency step size is greater than or equal to a frequency range covered by the second hopping sequence.
  • the label "R” indicates an example of the frequency range covered by the second hopping sequence
  • the label "S” indicates an example of the first frequency step size that is equal to "R”.
  • the first frequency step size may be less than the frequency range covered by the second hopping sequence.
  • U S could alternatively be less than R.
  • the hopping sequence is defined according to equation (1) as follows:
  • nk,l m k ' $ + s k,l [0154]
  • k represents a hop index of the first hopping sequence
  • / represents a hop index of the second hopping sequence
  • n k l l represents an z ' -th instance of a (k,l)-t frequency of the hopping sequence
  • m k l represents an i-th instance of a k-th element of the first hopping sequence
  • S represents the first frequency step size
  • s k l represents an z ' -th instance of a (k,l)-t element of the second hopping sequence.
  • the frequencies selected according to the determined frequency hopping sequence are disposed in unlicensed spectrum. Such frequencies could also be used in other contexts, such as eMTC or eMTC-U systems, Multefire systems, IoT systems, etc.
  • the method further comprises the wireless device performing channel estimation filtering across multiple frequency hops of the second hopping sequence.
  • channel estimation filtering is to decrease the effects of noise and interference on channel estimates.
  • the receiver filters (in time and/or frequency) raw channel estimates based on known reference symbols.
  • the filtering is typically done over units in time where the channel can be assumed to be fairly constant, which is assumed to be the case within the second hopping sequence.
  • performing the channel estimation filtering comprises filtering channel estimates across a time duration that spans the multiple frequency hops of the second hopping sequence.
  • the method further comprises the wireless device determining a difference between a current and previous frequency of the wireless device, and in response to determining that the difference is larger than a first threshold, resetting at least one channel estimation filter.
  • resetting a channel estimation filter generally entails discarding any states representing previous channel estimates and preparing the filter to process new raw channel estimates.
  • the method further comprises estimating a residual timing error and/or applying compensation for residual timing errors.
  • estimating a residual timing error can be done e.g. by estimating the max or center of gravity of the power delay profile of the channel and the compensation for residual timing errors can be done by applying a phase ramp in frequency corresponding to the estimated residual timing error to the raw channel estimates prior to filtering.
  • Modifications, additions, or omissions may be made to the systems and apparatuses described herein without departing from the scope of the disclosure.
  • the components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses may be performed by more, fewer, or other components.
  • each refers to each member of a set or each member of a subset of a set.

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Abstract

L'invention concerne un procédé destiné à un réseau de communication sans fil et comprenant les étapes consistant à : déterminer une séquence de sauts de fréquence à des fins de communication entre un dispositif sans fil et un nœud de réseau, cette séquence de sauts de fréquence étant une fonction d'une première séquence de sauts et d'une seconde séquence de sauts, la première séquence de sauts présentant une première taille de sauts de fréquence et une première longueur de séquence, la seconde séquence de sauts présentant une seconde taille de sauts de fréquence et une seconde longueur de séquence, la première taille de sauts de fréquence étant supérieure à la seconde taille de sauts de fréquence ; et communiquer sur des fréquences sélectionnées selon la séquence de sauts de fréquence déterminée.
PCT/IB2017/056553 2016-10-21 2017-10-20 Schéma de sauts de fréquence pour l'extension de couverture WO2018073812A1 (fr)

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EP3962190A1 (fr) 2020-08-26 2022-03-02 THALES DIS AIS Deutschland GmbH Procédé de commande de transmission de données dans un système de communication radio

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EP1216517A1 (fr) * 1999-09-28 2002-06-26 TELEFONAKTIEBOLAGET LM ERICSSON (publ) Diversite d'interferences dans des reseaux de communications a saut de frequence
WO2009136833A1 (fr) * 2008-05-06 2009-11-12 Telefonaktiebolaget L M Ericsson (Publ) Décalage de saut de fréquence destiné à des utilisateurs multiples réutilisant un créneau temporel (muros)

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Publication number Priority date Publication date Assignee Title
EP1216517A1 (fr) * 1999-09-28 2002-06-26 TELEFONAKTIEBOLAGET LM ERICSSON (publ) Diversite d'interferences dans des reseaux de communications a saut de frequence
WO2009136833A1 (fr) * 2008-05-06 2009-11-12 Telefonaktiebolaget L M Ericsson (Publ) Décalage de saut de fréquence destiné à des utilisateurs multiples réutilisant un créneau temporel (muros)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3962190A1 (fr) 2020-08-26 2022-03-02 THALES DIS AIS Deutschland GmbH Procédé de commande de transmission de données dans un système de communication radio
WO2022043310A1 (fr) 2020-08-26 2022-03-03 Thales Dis Ais Deutschland Gmbh Procédé de commande de la transmission de données dans un système de radiocommunication

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