HK1155601B - A method and a system for communication - Google Patents

Description

Communication method and communication system

Technical Field

The present invention relates to communication systems, and more particularly, to a method and/or system for implementing multiple frequency hypothesis testing (multiple frequency hypothesis testing) with full synchronization acquisition in an E-UTRA/LTE UE receiver.

Background

A variety of communication standards have been developed that can provide relatively high data rates to support high quality services, such as Evolved UMTS Terrestrial radio access (E-UTRA), also known as Long Term Evolution (LTE). LTE is a third Generation Partnership Project (3 GPP) standard that can provide uplink rates of up to 50Mbp, and downlink rates of up to 100 Mbps. The LTE/E-UTRA standard represents a significant advance in cellular technology. The LTE/E-UTRA standard can meet the current and even future carrier needs for high rate data and media transmission and high capacity voice support. The LTE/E-UTRA standard brings many technical advantages to cellular networks, including advantages provided by Orthogonal Frequency Division Multiplexing (OFDM) and/or multiple-input multiple-output (MIMO) data communications. In addition, Orthogonal Frequency Division Multiple Access (OFDMA) and single carrier frequency division Multiple Access (SC-FDMA) are used on the Downlink (DL) and Uplink (UL), respectively.

Mobility management (mobility management) is an important aspect of the LTE/E-UTRA standard. The transmission of synchronization signals and cell (cell) search procedure provide a basis for a mobile device or UE to probe and synchronize with various cells as the mobile device (also referred to as a user terminal (UE) in the LTE/E-UTRA standard) moves within the LTE/E-UTRA coverage area. In order to communicate with a particular cell, a mobile device within the coverage area of the relevant LTE/E-UTRA needs to determine one or more cell-specific transmission parameters such as symbol timing (symbol timing), radio frame timing (radio frame timing), and/or cell ID. In the LTE/E-UTRA standard, cell-specific information is carried by reference and/or synchronization signals. The latter forms the basis for mobile device Downlink (DL) synchronization and cell specific information identification within the relevant LTE/E-UTRA coverage area. Two Downlink (DL) synchronization signals, referred to as Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS), are used to allow a mobile device to synchronize with the transmission timing of a particular cell in order to acquire cell specific information such as a full physical cell ID and/or a cell ID group indicator.

Other drawbacks and disadvantages of the prior art will become apparent to one of ordinary skill in the art upon examination of the following system of the present invention as described in conjunction with the accompanying drawings.

Disclosure of Invention

The invention provides a multi-frequency hypothesis testing (multi-frequency hypothesis testing) method and/or system for realizing full synchronous acquisition in an E-UTRA/LTE UE receiver. As will be more fully shown and/or described in connection with at least one of the figures, and as set forth more completely in the claims.

According to an aspect of the present invention, a communication method is provided, including:

executing, by one or more processors and/or circuits in a mobile device:

receiving a Radio Frequency (RF) signal, wherein the received RF signal comprises a Primary Synchronization Sequence (PSS) and a Secondary Synchronization Sequence (SSS); and

decoding the received SSS in each multi-frequency hypothesis branch of a set of multi-frequency hypothesis (MFH) branches related to MFH testing.

Preferably, the method further comprises performing a PSS correlation process using a baseband signal of the received RF signal in each MFH branch of the MFH branch group.

Preferably, the method further comprises detecting the received PSS in each MFH branch of the set of MFH branches using the corresponding PSS correlation data.

Preferably, the method further comprises attempting to decode the SSS in each MFH branch of the set of MFH branches based on the PSS detection.

Preferably, the method further comprises attempting to acquire cell-specific (cell) information in each MFH branch of the MFH branch group based on the PSS detection and the SSS decoding.

Preferably, the acquired specific cell information in each MFH branch of the MFH branch group includes cell Identification (ID) information, Cyclic Prefix (CP) length, and reliability information (reliability information) and/or decoding attempt over consecutive half frames.

Preferably, the method further comprises selecting the MFH branch having the largest PSS correlation peak from the set of MFH branches after the acquiring.

Preferably, the method further comprises using the acquired specific cell information corresponding to the selected MFH branch to enable communication in a cell indicated by the corresponding acquired specific cell information.

Preferably, the method further comprises comparing the obtained cell ID information and/or CP length of the selected MFH branch with a corresponding portion of each remaining MFH branch in the MFH branch set to detect for correspondence with a corresponding portion of one or more remaining MFH branches in the MFH branch set.

Preferably, the method further comprises applying frequency offset estimates from the selected MFH branch after the comparison to achieve frequency control in the MFH test.

According to yet another aspect of the present invention, there is provided a communication system comprising:

one or more processors and/or circuitry for use in a mobile device, wherein the one or more processors and/or circuitry are configured to:

receiving a Radio Frequency (RF) signal, wherein the received RF signal comprises a Primary Synchronization Sequence (PSS) and a Secondary Synchronization Sequence (SSS); and

decoding the received SSS in each multi-frequency hypothesis branch of a set of multi-frequency hypothesis (MFH) branches related to MFH testing.

Preferably, the one or more processors and/or circuits are operable to perform a PSS correlation process using a respective baseband signal of the received RF signals in each MFH branch of the set of MFH branches.

Preferably, the one or more processors and/or circuits are operable to detect the received PSS in each MFH branch of the set of MFH branches using corresponding PSS correlation data.

Preferably, the one or more processors and/or circuits are configured to attempt decoding the SSS in each MFH branch of the set of MFH branches based on the PSS detection.

Preferably, the one or more processors and/or circuits are configured to attempt to obtain cell-specific information in each MFH branch in the MFH branch group based on the PSS detection and the SSS decoding.

Preferably, the acquired specific cell information in each MFH branch of the MFH branch group includes cell Identification (ID) information, Cyclic Prefix (CP) length, and reliability information (reliability information) and/or decoding attempt over consecutive half frames.

Preferably, the one or more processors and/or circuits are operable to select, after the obtaining, an MFH branch having a largest PSS correlation peak from the set of MFH branches.

Preferably, the one or more processors and/or circuits are configured to enable communication in a cell indicated by the corresponding obtained specific cell information using the obtained specific cell information corresponding to the selected MFH branch.

Preferably, the one or more processors and/or circuits are operable to compare the obtained cell ID information and/or CP length of the selected MFH branch to a corresponding portion of each remaining MFH branch in the set of MFH branches to detect correspondence with a corresponding portion of one or more remaining MFH branches in the set of MFH branches.

Preferably, the one or more processors and/or circuits are operable to apply frequency offset estimates from the selected MFH branch after the comparison to achieve frequency control in the MFH test.

The following detailed description of specific embodiments is provided to facilitate an understanding of various advantages, aspects, and novel features of the invention as they may be better understood when considered in connection with the accompanying drawings.

Drawings

FIG. 1 is a block diagram of an exemplary LTE/E-UTRA communication system for performing multiple frequency hypothesis testing with full synchronization acquisition in an E-UTRA/LTE UE receiver in accordance with an embodiment of the present invention;

FIG. 2 is a diagram of an exemplary E-UTRA/LTE downlink synchronization signal structure in accordance with an embodiment of the present invention;

FIG. 3 is a block diagram of an exemplary mobile device for performing multi-frequency hypothesis testing with full synchronization acquisition in an E-UTRA/LTE UE receiver in accordance with an embodiment of the present invention;

FIG. 4 is a diagram illustrating an exemplary receiver architecture for performing multi-frequency hypothesis testing with full synchronization acquisition in an E-UTRA/LTE UE receiver, in accordance with an embodiment of the present invention;

FIG. 5 is an exemplary multi-frequency hypothesis subsystem for performing multi-frequency hypothesis testing with full synchronization acquisition in an E-UTRA/LTE UE receiver, in accordance with an embodiment of the present invention;

fig. 6 is a flow diagram of an exemplary method for acquiring fully-synchronized acquisition information in a multi-frequency hypothesis test in an E-UTRA/lte ue receiver in accordance with an embodiment of the present invention.

Detailed Description

Various embodiments of the present invention propose a method and/or system to implement multiple frequency hypothesis testing with full synchronization acquisition in an E-UTRA/LTE UE receiver. The mobile device is configured to receive radio frequency signals from an associated base station. The received signals include a PSS and a SSS, which are used by mobile devices (also referred to as UEs) to acquire cell-specific parameters through PSS synchronization and SSS detection, respectively. To overcome the uncertainty of the correct PSS symbol timing and/or the correct frequency offset of the received PSS, the mobile device is configured to perform a Multiple Frequency Hypothesis (MFH) check. The mobile device is configured to perform MFH verification using a set of MFH branches. The mobile device is configured to decode the received SSS in each branch of the set of MFH branches. The mobile device is configured to perform the PSS correlation process for each MFH branch. The result-related data may be integrated in a plurality of radio frames, for example. The received PSS may be detected by selecting a candidate PSS for the received PSS based on the resulting PSS correlation peak amplitude. The resulting PSS detection information is used for SSS decoding per MFH branch. Cell-specific information, such as cell ID information and/or CP length information, for each MFH branch is obtained based on the respective PSS detection and SSS decoding in the MFH branch. After obtaining the specific cell information of each MFH branch, the mobile device is configured to select the specific MFH branch with the largest PSS correlation peak in the entire set of MFH branches. The cell-specific information of the selected MFH branch is used for communication within the corresponding cell. Additional detection of cell-specific information validity is performed by evaluating whether cell-specific information is consistently detected during PSS/SSS acquisition/detection. The mobile device is also configured to compare cell ID information and/or CP length information across the entire set of MFH branches for additional consistency detection, which increases the confidence of the particular cell information detected when such consistency exists. In the absence of a coherency indication, or a set of MFH branches, a frequency offset estimate for the selected MFH branch may be applied to the UE reference oscillator frequency in order to compensate for an initial frequency offset that exists between the base station carrier frequency and the UE local oscillation frequency.

Fig. 1 is a block diagram of an exemplary LTE/E-UTRA communication system for performing multiple frequency hypothesis testing with full synchronization acquisition in an E-UTRA/LTE UE receiver in accordance with an embodiment of the present invention. Referring to fig. 1, an LTE/E-UTRA communication system 100 is shown. The LTE/E-UTRA communication system 100 comprises a plurality of cells, of which cells 110 and 120 are shown. The LTE/E-UTRA coverage area 130 is the overlapping coverage area of cell 110 and cell 120. Cell 110 and cell 120 are associated with base station 110a and base station 120a, respectively. The LTE/E-UTRA communication system 100 includes a plurality of mobile devices, of which mobile device 112 is shown and 126. Mobile device 112 is located in cell 110 as well as 116. The mobile device 122 is located in the cell 120 as well as 126. The mobile device 118 and the mobile device 119 are located in an overlapping LTE/E-UTRA coverage area 130.

A base station, such as base station 110a, may comprise suitable logic, circuitry, interfaces and/or code that may be operable to manage various aspects of communication, such as communication connection establishment, connection maintenance and/or connection termination (termination), with associated mobile devices within cell 110. The base station 110a is configured to manage related radio resources such as radio bearer control (rb control), radio admission control (radio admission control), connection mobility control, and/or dynamic allocation of radio resources in the cell 110 in uplink and downlink communications. The base station 110a is configured to use physical channels and physical signals for uplink and downlink communications. The physical channel may carry information from higher layers for conveying user data as well as user control information. Physical signals such as synchronization signals cannot carry information from higher layers. In the LTE/E-UTRA standard, a base station 110a is used to transmit a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS).

The base station 110a is configured to transmit the PSS and SSS on a per 5ms basis in the last two OFDM symbols of the first and eleventh slots of each radio frame. The PSS is selected from a plurality of (a variety of) Zadhoff-Chu sequences, and carries identification information of a cell in a base station or a cell group. The SSS is a sequence that carries information about a cell group, encoded by a scrambling sequence, unique to the associated mobile device. The scrambling code is linked or mapped to, for example, the PSS index. After successful time and frequency synchronization by PSS synchronization, frame boundary synchronization and/or cell identification may be achieved by SSS detection. The transmission of PSS and SSS allows time and frequency offset issues to be handled before cell-specific information is determined. This will result in a reduction in the complexity of the initial cell search and/or handover modes associated with mobile devices such as mobile device 114 and mobile device 118.

A mobile device such as the mobile device 118 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to communicate with a base station such as the base station 110a to enable services supported in the LTE/E-UTRA standard, for example. To communicate with the base station 110a, the mobile device 118 is configured to determine one or more transmission parameters used by the base station 110 a. Such information may be obtained, for example, by decoding a Broadcast Channel (BCH) signal from the base station 110 a. To do so, the mobile device 118 needs to synchronize with the respective symbol timing and frame timing of the transmissions from the base station 110a to obtain certain cell parameters such as the relevant cell ID and/or antenna configuration. In this regard, the mobile device 118 may receive multiple PSS and SSS from neighboring or surrounding base stations, such as base station 110a and base station 120a, every 5 ms. The received plurality of PSS is of a base station or a particular cell.

The mobile device 118 is configured to detect or select a particular PSS from the received multiple PSS to acquire PSS synchronization. The detected PSS is used to estimate a channel. The resulting channel estimate is used to decode or detect the relevant SSS for frame boundary synchronization and cell group information identification. The mobile device 118 may use a variety of methods to detect or select a particular PSS of the received plurality of PSS. For example, the mobile device 118 can generate multiple related reference sequences (reference PSS), each for respectively associating or matching the received multiple PSS. For example, to accumulate PSS correlation data over one or more slot periods. The resulting correlation peak indicates the possible PSS symbol timing hypothesis under consideration. The mobile device 118 can detect the particular PSS based on the resulting correlation peak. Moreover, the mobile device 118 can employ the PSS correlation data to estimate a frequency offset associated with a particular PSS. There may be a large range of uncertainty about the correct PSS symbol timing and/or the correct frequency for a particular PSS due to, for example, transmission delay, doppler shift and/or oscillator drift.

Uncertainty of correct PSS symbol timing and/or frequency offset for a particular PSS may result in the mobile device 118 failing to detect the particular PSS when present and erroneously detecting the particular PSS when not present, or detecting the particular PSS but failing to estimate the correct PSS symbol timing and/or frequency offset, thereby losing data. In this regard, the mobile device 118 is configured to perform a plurality of frequency hypothesis tests for frequency offset estimation. A set of specified frequency offsets, such as +/-15ppm, is selected within the desired local oscillator frequency uncertainty range to uniformly cover the desired frequency uncertainty range. An proprietary frequency offset may be applied to or placed in each multi-frequency hypothesis (MFH) branch of the multi-frequency hypothesis test. The actual frequency of the selected frequency offset may be determined based on the desired frequency estimation resolution and available resources, such as available memory of the mobile device 118 in an initial phase of synchronization/signal acquisition. The received signal for the particular PSS is frequency-shifted at each MFH branch in accordance with the corresponding selected dedicated frequency offset. Signal frequency shifting may be achieved by frequency mixing.

The mobile device 118 is configured to perform the PSS correlation process for each MFH branch after frequency mixing. At each MFH branch, PSS correlation data is accumulated in one or more time slots. The resulting PSS correlation peaks (possible PSS symbol timing hypotheses) may be compared based on the correlation peak magnitude to select a candidate PSS for each MFH branch for the received PSS. The candidate PSS for each MFH branch may be selected based on the maximum correlation peak magnitude for the respective MFH branch. The selected candidate PSS is used to estimate the channel for each MFH. The resulting channel estimate is used to decode or detect the candidate SSS for each MFH branch for frame boundary synchronization, cell group information identification, and/or Cyclic Prefix (CP) length. A full synchronous fetch of each MFH branch is performed. In each MFH branch, cell-specific information such as cell ID and/or CP length is declared upon determination of local oscillator frequency offset. The mobile device 118 is configured to select the particular MFH branch indicated by the largest PSS correlation peak amplitude over the entire set of MFH branches. The mobile device 118 is used to initiate a camping zone (camping) on a particular cell using information from the particular MFH branch selected. When applying frequency estimates from selected MFH branches for frequency control, consistency of respective specific cell information, such as cell ID and/or CP length, of each MFH branch in successive detection attempts may be considered.

In an exemplary operation, the base station 110a is configured to perform communications in the cell 110 using physical channels and physical channels such as PSS and SSS. The base station 110a is used to regularly (e.g., once every 5 ms) transmit the base station specific PSS and SSS. To communicate with base station 110a, a mobile device, such as mobile device 118, is configured to obtain the PSS and SSS received from base station 110a to determine one or more transmission parameters. For example, the mobile device 118 can be configured to acquire PSS synchronization to identify PSS symbol timing and estimate the channel. The resulting channel estimates and identified PSS symbol timing are used to detect the received SSS, resulting in cell-specific parameters such as frame boundary synchronization and/or cell group information.

The mobile device 118 is configured to perform multiple frequency hypothesis testing, obtain PSS symbol timing and estimate local oscillator frequency offset. The multi-frequency hypothesis test begins with a set of specified frequency offsets, such as +/-15ppm, within an uncertainty range of the desired local oscillation frequency. The mobile device 118 is configured to assign a dedicated frequency offset to each MFH branch. Each different MFH branch is assigned a different dedicated frequency offset. In each MFH branch, the baseband signal associated with the received PSS is frequency shifted by the assigned dedicated frequency offset. A PSS correlation process is performed on the signal with the assigned, dedicated frequency offset to obtain the received PSS. The candidate PSS of the received PSS may be selected according to the resulting PSS correlation peak amplitude. The selected candidate PSS is used to decode or detect a candidate SSS, enabling frame boundary synchronization, cell group information identification, and/or Cyclic Prefix (CP) length. A full synchronous fetch of each MFH branch is performed. The particular MFH branch indicated by the largest PSS correlation peak magnitude over the entire set of MFH branches is selected. The specific cell information originating from the selected specific MFH branch is used by the mobile device 118 to turn on a camping area (camping) on the specific cell to obtain information from the network. When applying frequency estimates from selected MFH branches for frequency control, the consistency of the corresponding cell information for each MFH branch and the entire set of MFH branches in successive detection attempts may be considered.

Figure 2 is a diagram of an exemplary E-UTRA/LTE downlink synchronization signal structure in accordance with an embodiment of the present invention. Referring to fig. 2, a downlink radio frame 200 is shown. In the LTE/E-UTRA standard, the downlink radio frame 200 is divided into 20 equally sized slots, two consecutive ones of which are arranged in a subframe, such as subframe 210. Downlink synchronization signals, such as PSS210a and SSS 210b, may be transmitted from base stations, such as base station 110a and/or base station 110b, to associated mobile devices, such as mobile device 118, to enable the mobile device 118 to acquire the correct timing of the downlink radio frame 200 and to acquire certain cell parameters, such as an associated cell ID and/or antenna configuration.

PSS210a and SSS 210b are transmitted on subframes 0 and 5 of downlink radio frame 200, PSS210a and SSS 210b occupying two consecutive symbols in the respective subframe. The PSS210a is used to identify the symbol timing and the cell ID in the cell ID group. The SSS 210b is used to identify frame boundaries, detect cell ID groups, and/or acquire system parameters such as Cyclic Prefix (CP) length. After successful PSS synchronization on PSS210a, SSS detection for SSS 210b is initiated. The PSS synchronization may provide time and frequency offset information for the downlink radio frame 200. To obtain accurate time and frequency offset information for downlink radio frame 200, a multi-frequency hypothesis test is performed. The PSS correlation process of PSS210a is combined with the frequency offset estimation in each MFH branch. After detecting the PSS210a, the SSS 210b for each MFH branch is detected, obtaining cell-specific parameters such as cell ID and/or Cyclic Prefix (CP) length.

Fig. 3 is a block diagram of an exemplary mobile device for performing multi-frequency hypothesis testing with full synchronization acquisition in an E-UTRA/LTE UE receiver, in accordance with an embodiment of the invention. Referring to fig. 3, a mobile device 300 is shown including an antenna 310, a transceiver 320, a main processor 330, and a memory 332. Transceiver 320 includes a Radio Frequency (RF) receiver (Rx) front end 324, a Radio Frequency (RF) transmitter (Tx) front end 326, and a baseband processor 322.

The antenna 310 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to transmit and/or receive electromagnetic signals. Although a single antenna is shown, the present invention is not so limited. In this regard, the transceiver 320 may be configured to transmit and receive radio frequency signals conforming to one or more wireless standards using a common antenna, may use different antennas (supporting wireless standards), and/or may use multiple antennas (supporting wireless standards). Various multi-antenna configurations may employ, for example, smart antenna techniques, diversity, and/or beamforming.

The transceiver 320 may comprise suitable logic, circuitry, interfaces and/or code that may be enabled to transmit and/or receive RF signals in accordance with one or more wireless standards, such as the E-UTRA/LTE standard.

The RF Rx front end 324 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to process RF signals received via the antenna 310 from, for example, an LTE/E-UTRA air interface. The RF Rx front-end 324 is used to convert the received RF signals into corresponding baseband signals. The resulting baseband signal is passed to baseband processor 322 for further baseband processing.

The RF Tx front-end 326 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to process an RF signal for transmission. The RF Tx front end 326 is used to receive baseband signals from the baseband processor 322 and convert the baseband signals to corresponding RF signals for transmission through the antenna 310.

The baseband processor 322 may comprise suitable logic, circuitry, interfaces and/or code that may enable managing and/or controlling the operation of the RF Rx front end 324 and the RF Tx front end 326, respectively. The baseband processor 322 is used to exchange baseband signals with the transceiver 320. The baseband processor 322 is used to process baseband signals to be forwarded to the RF Tx front end 326 for transmission and/or to process baseband signals from the RF Rx front end 324. The received baseband signals include synchronization signals such as PSS and SSS. The received PSS and SSS are used to obtain the transmission time and other cell-specific parameters such as the associated cell ID and/or antenna configuration of the associated cell. In this regard, the baseband processor 322 is configured to generate a plurality of associated reference sequences (reference PSS) in order to obtain the correct PSS timing and/or frequency offset.

Various factors, such as transmission delay, doppler shift, and/or oscillator drift, will result in a large range of uncertainty in the correct PSS symbol timing and/or frequency offset. In this regard, the baseband processor 322 is operable to perform multiple frequency hypothesis testing to obtain the correct PSS symbol timing and/or frequency offset estimates. The PSS correlation process for each MFH branch is performed using frequency offset estimation. The baseband processor 322 initiates a multi-frequency hypothesis test with a set of proprietary frequency offsets. The selected set of tailored frequency offsets uniformly covers a desired local oscillator frequency uncertainty range such as +/-15 ppm. Each MFH branch is associated with a particular dedicated frequency offset selected by baseband processor 322. In each MFH branch, a baseband processor 322 is used to apply a proprietary frequency offset to the received baseband signal. The baseband processor 322 is configured to perform the PSS correlation process for signals with the specified frequency offset. The candidate PSS for the received PSS for each MFH branch is selected according to the resulting PSS correlation peak magnitude.

The selected candidate PSS is used to decode or detect the candidate SSS for each MFH branch. For example, in each MFH branch, the PSS-specific scrambling code of the SSS process is identified. In addition, the selected candidate PSS is used to estimate a channel. The resulting channel estimate is used to decode or detect the candidate SSS for each MFH branch for frame boundary synchronization, cell group information identification, and/or Cyclic Prefix (CP) length. The baseband processor 322 is operable to communicate normally with a corresponding base station, such as base station 110a, using information from the particular MFH branch selected. When applying frequency estimates from the selected MFH branch for frequency control, certain cell information such as cell ID and/or CP length consistency may be taken into account.

The main processor 330 may comprise suitable logic, circuitry, interfaces and/or code that may enable operation and control of the transceiver 320. The main processor 130 may exchange data with the transceiver 320 to support applications such as audio streaming on the mobile device 300.

The memory 332 may comprise suitable logic, circuitry, interfaces and/or code that may enable storage of information such as executable instructions and data used by the main processor 330 and the baseband processor 322. The executable instructions include algorithms applied to various baseband signal processing such as synchronization and/or channel estimation. Memory 322 includes RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage.

In an exemplary operation, the RF Rx front end 124 is used to process RF signals received by, for example, the antenna 310 over the LTE/E-UTRA air interface. The received RF signals include PSS and SSS transmitted by base stations, such as base station 110a and/or base station 120 a. The received RF signals are converted to corresponding baseband signals and passed to a baseband processor 322 for further baseband processing. To communicate with a particular base station, such as base station 110a, baseband processor 322 is configured to synchronize with a particular cell transmission time, such as the symbol timing and frame boundary used by base station 110 a. In this regard, the baseband processor 322 is configured to generate a plurality of correlation reference sequences (reference PSS) to acquire PSS synchronization. To obtain accurate PSS symbol timing and/or frequency offset, baseband processor 322 is operable to perform multiple frequency hypothesis testing. A set of specified frequency offsets, such as +/-15ppm, is selected within a desired local oscillation frequency uncertainty range to enable a multiple frequency hypothesis test. The baseband processor 322 is used to set a specific dedicated frequency offset in each MFH branch. The baseband signal associated with the received PSS may be frequency shifted by frequency mixing. After frequency mixing, the PSS correlation process for each MFH branch is performed.

The candidate PSS for the received PSS for each MFH branch is selected according to the corresponding resulting PSS correlation peak magnitude. In each MFH branch, a baseband processor 322 is used to estimate a channel to decode or detect a candidate SSS using the received candidate PSS. Cell-specific information such as cell ID and/or CP length for each MFH branch is obtained from the corresponding decoded candidate SSS. The particular cell information from the particular MFH branch selected is used to enable normal communications with the corresponding base station, such as base station 110 a. When applying frequency estimates from the selected MFH branch for frequency control, consistency of detected cell-specific information for the selected MFH branch and the entire set of MFH branches in successive detection attempts may be considered.

Fig. 4 is a diagram illustrating an exemplary receiver architecture for performing multi-frequency hypothesis testing with full synchronization acquisition in an E-UTRA/LTE UE receiver, in accordance with an embodiment of the invention. Referring to fig. 4, a receiver 400 is shown. The receiver 400 includes a receiver Radio Frequency (RF) front end 410, a baseband processor 420, a local oscillator 430, and a frequency control unit 440. The receiver RF front end 410 includes a Low Noise Amplifier (LNA)412, a mixer 414, a Low Pass (LP) filter 416, and a Variable Gain Amplifier (VGA) 418. Baseband processor 420 includes an analog-to-digital converter (ADC)422, a multi-frequency hypothesis testing subsystem 424, a processor 426, and a memory 428.

The receiver RF front end 410 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to process RF signals received by the antenna 310. The received RF signals include PSS and SSS. The receiver RF front end 410 is used to convert the received RF signals to corresponding baseband frequency signals for further processing by the baseband processor 420.

The LNA412 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to amplify the RF signals received by the antenna 310. The LNA412 is used to set the system noise figure lower limit. The LNA412 is capable of achieving low noise performance, which is important for high performance Radio Frequency (RF) front ends.

Mixer 414 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to convert the amplified RF signal from LNA412 to a low Intermediate Frequency (IF) signal using a signal provided by local oscillator 430, which may be driven by a reference frequency provided by frequency control unit 440.

The LP filter 416 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to filter the IF signal from the mixer 414 to enable removal of undesired signal components. The LP filter 416 is used to convert the resulting IF signal to an analog baseband signal.

The VGA 418 comprises suitable logic, circuitry, interfaces and/or code that may be operable to amplify the analog baseband signal from the LP filter 416. The VGA 418 is used to apply different gains to the analog baseband signal, generating variable signal levels as inputs to the ADC 422.

The ADC 422 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to convert an analog baseband signal received from the VGA 418 in the receiver RF front end 410 to a corresponding digital baseband signal at an analog-to-digital sampling frequency of, for example, 30.72MHz, which may be derived from a reference frequency provided by the frequency control unit 440. The resulting digital baseband signal includes a value representing the amplitude of the analog baseband signal. The digital baseband signal is sent to the MFH subsystem 424 for the correct PSS time and frequency offset. The digital baseband signal is passed to processor 426 for additional baseband processing such as SSS detection.

The MFH subsystem 424 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to perform multiple frequency hypothesis testing to obtain an accurate PSS time and/or frequency offset estimate. The MFH subsystem 424 is used to initiate a multi-frequency hypothesis test using a set of proprietary frequency offsets selected within a desired local oscillator frequency uncertainty range, such as +/-15 ppm. The MFH subsystem 424 is used to set a specific frequency offset in each MFH branch. The MFH sub-system 424 is used to apply frequency offset to baseband signals through frequency mixing. The PSS correlation process is performed for each MFH branch after frequency mixing. The MFH subsystem 424 is configured to select candidate PSS for the received PSS for each MFH branch based on the corresponding PSS correlation peak magnitude.

The MFH subsystem 424 is used to perform SSS detection or decoding for each MFH based on the respective selected candidate PSS. The MFH subsystem 424 is used to perform fully synchronous fetches in each MFH branch. In local oscillator frequency offset determination, relevant cell-specific information such as cell ID and/or CP length may also be determined. The particular MFH branch indicated by the highest PSS correlation peak magnitude is selected among the entire set of MFH branches of the MFH subsystem 424. Consistency of selected MFH branch cell ID information and/or CP length information is evaluated over the entire set of MFH branches of the MFH sub-system 424. Depending on the consistency of the cell ID information and/or CP length information of the selected MFH branch, the frequency estimation of the selected MFH branch is applied, even though the consistency information is not necessary for applying the frequency offset indicated by the selected MFH branch to the local oscillator 430 by the frequency control unit 440. The MFH sub-system 424 is operable to communicate particular cell information from the selected particular MFH branch to the processor for normal communication with a corresponding base station, such as base station 110 a.

The processor 426 may comprise suitable logic, circuitry, interfaces and/or code that may enable processing of the digital baseband signals from the ADC. Processor 426 is configured to perform various baseband operational procedures such as channel equalization using information from MFH sub-system 424.

The memory 428 may comprise suitable logic, circuitry, interfaces and/or code that may enable storage of executable instructions and data for use by associated components, such as the processor 426 in the receiver 400. The executable instructions include algorithms applied to various baseband operations such as channel estimation, channel equalization, and/or channel coding. The data includes time and/or frequency offset hypotheses. Memory 428 includes RAM, ROM, low latency nonvolatile memory such as flash memory and/or other suitable electronic data storage.

The local oscillator 430 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to provide a mixing signal to the mixer 414 of the receiver 400. The local oscillator 430 is used to adjust the frequency based on the reference signal provided by the frequency control unit 440 according to the frequency offset estimate provided by the MFH subsystem 424.

The frequency control unit 440 may comprise suitable logic, circuitry, interfaces and/or code that may enable controlling the setting of the respective reference frequencies of the local oscillator 430 and the ADC 422. The frequency control unit 440 is used to adjust the reference frequencies of the local oscillator 430 and the ADC 422, respectively, according to the frequency offset estimate of the MFH sub-system 424. The operation of the frequency control unit 440 is to control the time and/or the local oscillation frequency of the receiver 400.

In an exemplary operation, receiver 400 is used to receive RF signals from, for example, an antenna. The received RF signals include PSS and SSS. The receiver RF front end 410 is used to amplify the received RF signal by the LNA412 and convert it to a baseband signal by the mixer 414 and the LP filter 416. The baseband signal is amplified by VGA 418 and converted to a digital baseband signal by ADC 422. The digital baseband signals are processed by the MFH subsystem 424 to obtain accurate PSS time and/or frequency offset estimates. The MFH subsystem 424 is used to offset the frequency of the digital baseband signal using the selected dedicated frequency offset for each MFH branch. The actual frequency of the selected dedicated frequency offset is determined based on the desired frequency estimation resolution and available resources, such as available resources in an initial phase of synchronization/signal acquisition. The PSS correlation process for each MFH branch is performed.

The MFH subsystem 424 is used to perform SSS detection after PSS process execution for each MFH branch. The MFH subsystem 424 is used to perform fully synchronous fetches in each MFH branch. The MFH subsystem 424 is used to select the particular MFH branch indicated by the highest PSS correlation peak magnitude over the entire set of MFH branches. The particular cell information, such as the cell ID and/or CP length, for the particular MFH branch selected is communicated to processor 426 for normal communication by the corresponding base station, such as base station 110 a. Depending on the consistency of the cell ID information and/or CP length information of the selected MFH branch, frequency offset estimation of the selected MFH branch may be applied for frequency control, which may further enhance the confidence in the estimated frequency offset. Although consistency in the detected SSS-related information is not a strict requirement for applying the frequency offset information indicated by the selected MFH branch.

Figure 5 is an exemplary multiple frequency hypothesis subsystem for performing multiple frequency hypothesis testing with full synchronization acquisition in an E-UTRA/LTE UE receiver, in accordance with an embodiment of the present invention. Referring to fig. 5, the MFH subsystem 500 is shown to include a mix generator 510, a set of MFH branches, of which MFH branch 520 and 560 are shown, and an MFH branch selector 570. An MFH branch, such as MFH branch 520, includes a mixer 522, a PSS correlator 524, and an SSS detector 526. The PSS correlator 524 includes a matched filter 524a, a synthesizer 524b, a PSS detector 524c, and a frequency offset estimator 524 d. The SSS detector 526 includes an SSS processor 526a and an SSS decoder 526 b.

The mix generator 510 may comprise suitable logic, circuitry, interfaces and/or code that may enable generation of a plurality of mixes for the MFH branch 520 and 560. The mix generator 510 is used to generate a plurality of mixes, placing a specific frequency offset, such as +/-0.5ppm, in the MFH branch. The actual frequency of the generated mix may be determined based on the desired frequency estimation resolution and in accordance with available system resources, such as memory. The generated mixing frequency indicates a corresponding time and/or frequency offset. The mix generator 510 is used to generate the mix such that the resulting frequency offset is within a desired local oscillator frequency uncertainty range, such as +/-15 ppm. The resulting mixing is passed to MFH branches 520-560, where the digital baseband signal of each MFH branch is shifted by a desired, dedicated offset to obtain an accurate time and/or frequency offset estimate.

An MFH branch, such as MFH branch 520, may comprise suitable logic, circuitry, interfaces and/or code that may enable performing accurate frequency offset estimation using a specified frequency offset indicated by the mixing frequency from the mixing frequency generator 510. The MFH branch 520 is used to shift the frequency of the digital baseband signal from the ADC 422 by a mixer 522. The MFH branch 520 is used to perform PSS correlation procedures on the digital baseband signal generated by the application of the proprietary frequency offset through a PSS correlator 524. The MFH branch 520 is used to perform SSS detection for each MFH branch after PSS correlation procedure, by SSS detector 526, resulting in cell-specific information. Full synchronous fetch is performed in the MFH branch 520 to achieve fast synchronous fetch. In the MFH branch 520, relevant cell-specific information such as cell ID and/or CP length is also available when transmitting the frequency offset determination.

A mixer such as the mixer 522 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to mix the digital baseband signal received from the ADC 422 with the mixing frequency from the mixing frequency generator 510. The mixing indicates the specific frequency offset selected for the MFH branch 520.

A PSS correlator such as PSS correlator 524 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to perform a correlation process to acquire PSS synchronization. The PSS correlator 524 is used to perform a correlation process on the signal from the mixer 522 through a matched filter 524 a. The resulting PSS correlation data is transmitted to the synthesizer 524b to identify possible PSS time hypotheses.

A matched filter, such as matched filter 524a, may comprise suitable logic, circuitry, interfaces and/or code that may be operable to correlate the signal from the mixer 522 with each of the plurality of local reference PSS. The resulting PSS correlation data may be provided to synthesizer 524 b.

A synthesizer such as synthesizer 524b may comprise suitable logic, circuitry, interfaces and/or code that may be operable to aggregate PSS correlation data from matched filter 524a, for example, over one or more slot intervals. The result is that the PSS correlation peak indicates the possible PSS symbol timing hypothesis under consideration.

The PSS detector 524c may comprise suitable logic, circuitry, interfaces and/or code that may be operable to identify a candidate PSS based on the maximum correlation peak amplitude output by the synthesizer 524 b. The location of the maximum correlation peak indicates the PSS symbol timing of the identified candidate PSS in the MFH branch 520. The identified candidate PSS and PSS symbol timings are passed to the MFH branch selector 570 to select a particular MFH branch among the entire set of MFH branches.

A frequency offset estimator, such as frequency offset estimator 524d, may comprise suitable logic, circuitry, interfaces and/or code that may be operable to estimate the remaining frequency offset in MFH branch 520. In this regard, frequency offset estimator 524d is configured to estimate the residual frequency offset in MFH branch 520 using the PSS correlation data from matched filter 524 a.

The MFH branch selector 570 may comprise suitable logic, circuitry, interfaces and/or code that may be operable to select a particular MFH branch from the entire set of MFH branches in the MFH subsystem 500. The MFH branch selector 570 is configured to determine a particular MFH branch based on the magnitude of the largest PSS correlation peak. The selected MFH branch may be indicated by the largest PSS correlation peak over the entire set of MFH branches 520 and 560. As part of the SSS processing in the SSS processor 526a and decoder 526b, consistency of the decoded information for each MFH branch is established and declared. MFH branch picker 570 is also used to verify the consistency of cell ID information and CP length information across the entire set of MFH branches in MFH sub-system 424. For example, MFH branch selector 570 is operable to compare information on the entire set of MFH branches, such as cell ID information and/or CP length information. Assuming that the cell information and CP length information of the selected MFH branch are identical to other MFH branches in the entire set of MFH branches, the confidence level of the cell ID information and/or CP length information of the selected MFH branch may be increased. MFH branch selector 570 is operable to communicate the frequency estimate for the selected MFH branch to frequency control unit 440. The frequency control unit 440 is further configured to apply frequency offset estimation of the selected MFH branch to frequency control according to consistency of cell ID information and/or CP length information of the selected MFH branch. Although consistency of SSS-related information is not necessary for feeding back frequency offset information to the frequency control unit 440. In the absence of consistent information, the selected MFH branch may still provide a useful frequency offset estimate, which may be fed back to the frequency control unit 440. MFH branch selector 570 is operative to communicate particular cell information from the selected branch to processor 426. The specific information includes symbol timing, frame timing, cell ID, and/or CP length. The processor 426 is configured to communicate in the corresponding cell using the cell-specific information.

In an exemplary operation, MFH subsystem 500 is used to receive a corresponding digital baseband signal, such as an RF signal from antenna 310. The received RF signals include PSS and SSS. The received digital baseband signals of each MFH branch are processed to derive the precise time and/or frequency offset of the respective transmission. In each MFH branch, such as MFH branch 520, the digital baseband signal may be frequency shifted by mixer 522. The mixer 522 is used to communicate with the mix generator 510 to obtain a particular mix. The particular mixing indicates the specific frequency offset of the digital baseband signal in the MFH branch 520. The mixing is selected such that the resulting tailored frequency offset is within a desired local oscillator frequency uncertainty, such as +/-15 ppm. The PSS correlation process is performed by PSS correlator 524 on the signal from mixer 522. The matched filter 524a is used to associate the received signal with each of the plurality of local reference PSS. The resulting correlation data is delivered to synthesizer 524 b. The synthesizer 524b is used to accumulate PSS correlation data from the matched filter 524a, for example, in one slot period. The resulting correlation peak indicates the possible PSS symbol timing hypothesis under consideration.

The PSS detector 524c is used to identify a candidate PSS for the received PSS based on the maximum correlation peak amplitude. Frequency offset estimator 524d is used to estimate the residual frequency offset in MFH branch 520 using the PSS correlation data received from matched filter 524 a. MFH branch selector 570 is used to select a particular MFH branch over the entire set of MFH branches, such as MFH branch 520-560. A particular MFH branch is selected based on the highest PSS correlation peak magnitude. MFH branch selector 570 is operative to communicate resulting cell-specific information from the selected particular MFH branch to processor 426 for additional baseband signal processing such as channel equalization and/or frequency control. The MFH branch selector 570 is configured to check consistency of cell ID information and CP length information over the entire set of MFH branches, and compare whether there is consistent information for the selected MFH branch. The frequency estimates from the selected MFH branch are applied by frequency control unit 440, based first on the maximum PSS correlation peak amplitude, and again for additional confidence assurance, based on the consistency of the cell ID information and CP length information of the selected MFH branch with other MFH branches in the entire set of MFH branches. However, the absence of consistent information does not prevent feedback of the frequency offset estimate indicated by and taken from the selected MFH branch. In the absence of the consistency information, it is not possible to determine relevant SSS information and corresponding information related to the base station such as cell ID in use and cyclic prefix length, but this does not prevent feedback of the resulting frequency offset.

Fig. 6 is a flow diagram of an exemplary method for acquiring fully-synchronized acquisition information in a multi-frequency hypothesis test in an E-UTRA/lte ue receiver in accordance with an embodiment of the present invention. Exemplary steps begin at step 602. In step 602, the MFH branch selector 570 is configured to receive cell-specific information from each of the entire set of MFH branches, such as MFH branches 520 and 560. Cell-specific information may be acquired through PSS synchronization and/or SSS detection for each MFH branch. In step 604, the MFH branch selector 570 is configured to sort the entire set of MFH branches, such as MFH branches 520-560, according to the magnitude of the corresponding maximum PSS correlation peak. In step 606, an MFH branch, such as MFH branch 520, is selected among the entire set of MFH branches 520-560 based on the highest PSS correlation peak magnitude. In step 608, MFH branch selector 570 is used to check the cell ID information and CP length over the entire set of MFH branches. In step 610, it is determined whether the cell ID information and CP length information in the selected MFH branch coincide with the cell ID information and CP length information in other MFH branches. Assuming the cell ID information and CP length information are consistent with other MFH branches in the entire set of MFH branches, the confidence or quality of the corresponding cell ID information and CP length information in the selected MFH branch, which is then used to establish communication with base station 110a, is increased at step 612. Assuming that no consistent information is detected in the selected branch or other MFH branches of the entire set of MFH branches, it is not possible to reliably establish cell ID and/or CP length information, and additional processing is required to establish this information. In step 614, the MFH subsystem 424 operates to pass the frequency offset estimate from the selected MFH branch to the frequency control unit 440 for application to frequency control, regardless of whether consistent cell ID and CP length information is detected.

In step 610, assuming the cell ID information and/or CP length information is inconsistent with other MFH branches in the entire set of MFH branches, the exemplary step proceeds to step 614. Assuming that no consistent information exists in the selected MFH branch, it is not possible to make declarations about the cell ID and CP length in use. In this case, the frequency offset estimate obtained from the selected MFH branch is still fed back to frequency control unit 440. In this case, after feeding back the original estimated frequency offset information, which in turn improves the quality of the baseband signal used to establish the SSS-related information, additional SSS processing is required to establish more trusted cell ID and CP length information.

The present invention provides a method and system for implementing multiple frequency hypothesis testing with fully synchronous acquisition in an E-UTRA/LTE UE receiver. A mobile device, such as mobile device 114, is configured to receive Radio Frequency (RF) signals from an associated base station 110 a. The received signals include PSS and SSS. The received PSS and SSS are used by the mobile device 114 (also referred to as a UE) to acquire cell-specific parameters through PSS synchronization and SSS detection. To overcome the uncertainty of the correct PSS symbol timing and/or the correct frequency offset of the received PSS, mobile device 114 is configured to perform a Multiple Frequency Hypothesis (MFH) check through MFH subsystem 424. MFH subsystem 424 is used to perform MFH checks using a set of MFH branches, such as MFH branch 520-560.

The mobile device 114 is configured to decode the received SSS in each branch of the set of MFH branches. For example, in the MFH branch 520, SSS decoding is performed by SSS decoder 526b in SSS detector 526. The mobile device 114 is configured to perform the PSS correlation process for each MFH branch. For example, in the MFH branch 520, the PSS correlation process is performed by the PSS correlator 524. The matched filter 524a is used to associate the received signal of the PSS with each local reference PSS. The resulting correlation data output by matched filter 524a may be combined by combiner 524b in one or more time slots. PSS detection may be performed based on the resulting PSS correlation peak amplitude and by selecting candidate PSS for the received PSS. The resulting PSS detection information is used to provide SSS decoder for each MFH branch. Cell-specific information such as cell ID information and/or CP length information for each MFH branch is obtained based on respective PSS detection and SSS decoding. After successfully obtaining the cell-specific information for each MFH branch, MFH branch selector 570 is configured to select the particular MFH branch with the largest PSS correlation peak in the entire set of MFH branches. The cell-specific information of the selected MFH branch is used by processor 426 for intra-cell communication corresponding to the cell ID. MFH branch selector 570 is configured to compare the cell ID information and/or CP length information across the entire set of MFH branches, such as MFH branch 520 and 560, to determine whether the cell ID information and/or CP length information are consistent. The frequency estimation of the selected MFH branch may be applied regardless of whether the cell ID information and/or CP length information of the selected branch are consistent.

Another embodiment of the present invention provides a machine and/or computer readable storage and/or medium, having stored thereon, a machine code and/or a computer program having at least one code section executable by a machine and/or a computer, thereby enabling the machine and/or computer to perform the steps described herein for implementing multiple frequency hypothesis testing with fully synchronous acquisition in an E-UTRA/lte ue receiver.

In general, the invention can be implemented in hardware, software, firmware, or a combination thereof. The present invention can be realized in an integrated manner in at least one computer system or in a separate manner by placing different components in a plurality of interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware, software, and firmware may be a specialized computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein.

The present invention can also be implemented by a computer program product, which comprises all the features enabling the implementation of the methods of the invention and which, when loaded in a computer system, is able to carry out these methods. The computer program in the present document refers to: any expression, in any programming language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following a) conversion to another language, code or notation; b) reproduced in different formats to implement specific functions.

While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims (10)

1. A method of communication, comprising:

executing, by one or more processors and/or circuits in a mobile device:

receiving a Radio Frequency (RF) signal, wherein the received RF signal comprises a Primary Synchronization Sequence (PSS) and a Secondary Synchronization Sequence (SSS);

calculating correlation peak amplitudes for the received RF signals in each of a plurality of multi-frequency hypothesis (MFH) branches associated with MFH testing; and

decoding the received SSS in each of the plurality of MFH branches based on one or more channel characteristics associated with an MFH branch of the plurality of MFH branches having a largest correlation peak magnitude.

2. The method of claim 1, further comprising performing a PSS correlation process using a baseband signal of the received RF signal in each MFH branch of the set of MFH branches.

3. The communications method of claim 2, further comprising detecting the received PSS in each MFH branch of the set of MFH branches using corresponding PSS correlation data.

4. The method of communicating of claim 3, further comprising attempting to decode the SSS in each MFH branch of the set of MFH branches based on the PSS detection.

5. The communications method of claim 4, further comprising attempting to obtain cell-specific information in each MFH branch of the MFH branch group based on the PSS detection and the SSS decoding.

6. A communication system, the system comprising:

one or more processors and/or circuitry for use in a mobile device, wherein the one or more processors and/or circuitry are configured to:

receiving a Radio Frequency (RF) signal, wherein the received RF signal comprises a Primary Synchronization Sequence (PSS) and a Secondary Synchronization Sequence (SSS);

calculating correlation peak amplitudes for the received RF signals in each of a plurality of multi-frequency hypothesis (MFH) branches associated with MFH testing; and

decoding the received SSS in each of the plurality of MFH branches based on one or more channel characteristics associated with an MFH branch of the plurality of MFH branches having a largest correlation peak magnitude.

7. The communication system according to claim 6, wherein said one or more processors and/or circuits are operable to perform a PSS correlation process in each MFH branch of said set of MFH branches using a respective baseband signal of said received RF signals.

8. The communication system according to claim 7, wherein said one or more processors and/or circuits are operable to detect said received PSS in each MFH branch of said set of MFH branches using corresponding PSS correlation data.

9. The communication system according to claim 8, wherein said one or more processors and/or circuits are operable to attempt decoding the SSS in each MFH branch of the set of MFH branches based on the PSS detection.

10. The communication system according to claim 9, wherein said one or more processors and/or circuits are operable to acquire cell-specific information in each MFH branch of the MFH branch group based on said PSS detection and said SSS decoding attempt.