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Saturday 31 December 2016



1 - 5 YearsHyderabad / SecunderabadINR 6,00,000 - 16,00,000 P.A. Qualcomm provides our employees some of the best benefits in the industry. Please see www.qualcomm.com > Company > Careers > Benefits for more information.

Job Description

QCT's RF Systems team is in search of candidates to develop and support RF Systems for cellular phone applications(LTE, TD-SCDMA, UMTS, CDMA) from concept phase to customer sampling. This system is comprised of chipset, SW and HW, and analysis of RF performance is analyzed with Matlab, spreadsheets, and other tools. Develop IC specifications and system algorithms working with ASIC designers and System Engineers. Sustaining efforts for on-going chip designs including spreadsheet analysis. Presenting to technical audiences and able to write technical reports. Chipset integration of HW/SW/Firmware. Support Applications Engineering team through customer visits for marketing and training purposes.

Salary: INR 6,00,000 - 16,00,000 P.A. Qualcomm provides our employees some of the best benefits in the industry. Please see www.qualcomm.com > Company > Careers > Benefits for more information.
Industry: Semiconductors Electronics
Functional Area: Engineering DesignR&D
Role Category: Fresher
Role: Fresher
Keyskills:

Desired Profile


  • Masters/Phd degree in RF/Systems engineering plus 2-10 years industry experience
  • Experience/expertise in some of the following areas: Receiver/transmitter spreadsheet analysis, physical layer modeling, PLL/synthesizer design, GPS receiver design, frequency planning, PA design, cellular handset design, and circuit design.
  • Candidate must be proficient with Matlab and Excel
  • Knowledge of Stochastic processes (e.g. AWGN), basic electromagnetics (especially fading, antenna theory, and propagation), Fourier analysis, and RF theory (S parameters, matching, noise figure, stability, etc.)
  • Apply Job




  • Friday 30 December 2016


    2g/3g RF Optimization Expert

    Posted byVisionTel
    Posted dateWed, 21st Dec
    LocationMiddle East / West Asia
    Looking for 2G/3G optimization Expert for 1 year and extendable contract in Saudi Arabia.Nokia Experience is must.



    Send your resumes at: careers@visiontel.co

    Job Title2g/3g RF Optimization Expert
    Post Details
    Posted ByVisionTel
    Start DateASAP
    SalaryNegotiable
    Email Addresscareers@visiontel.co
    Category
    Job TypeContract
    LocationMiddle East / West Asia
    City or StateSaudi Arabia


    LTE Drive Test Parameters


    Some important indicator LTE drive test parameters:

    1. RSRP : Reference Signal Received Power.
    2. RSRQ : Reference Signal Received Quality.
    3. RSSI : Received Signal Strength Indicator.
    4. SINR : Signal to Interference Noise Ratio.
    5. CQI : Channel Quality Index.
    6. PCI : Physical Cell Identity.
    7. BLER: Block Error Ratio.
    8. DL Throughput : Down Link Throughput.
    9. UL Throughput : Up Link Throughput

    This is the common key performance parameters for LTE drive test parameter we have to work out for LTE drive test task.
    1. RSRP:
    RSRP – The average power received from a single Reference signal, and Its typical range is around -44dbm (good) to -140dbm(bad).
    RSRP (dBm) = RSSI (dBm) – 10*log (12*N)


    RSRQ Formula
    Reference Signal Received Quality (RSRQ) is defined as the ratio N×RSRP/(E-UTRA carrier RSSI),
    where N is the number of RB’s of the E-UTRA carrier RSSI measurement bandwidth.
    The measurements in the numerator and denominator shall be made over the same set of resource blocks.
    3. RSSI:
    RSSI – Represents the entire received power including the wanted power from the serving cell as well as all co-channel power and other sources of noise and it is related to the above parameters through the following formula:
    RSRQ=N*(RSRP/RSSI)

    Where N is the number of Resource Blocks of the E-UTRA carrier RSSI measurement bandwidth.
    RSSI (Received Signal Strength Indicator) is a parameter which provides information about total received wide-band power (measure in all symbols) including all interference and thermal noise. RSSI is not reported to e-NodeB by UE. It can simply be computed from RSRQ and RSRP that are, instead, reported by UE.
    RSSI = wideband power = noise + serving cell power + interference power
    So, without noise and interference, we have that 100% DL PRB activity: RSSI=12*N*RSRP
    Where:
    • RSRP is the received power of 1 RE (3GPP definition) average of power levels received across all Reference Signal symbols within the considered measurement frequency bandwidth
    • RSSI is measured over the entire bandwidth
    • N, number of RBs across the RSSI, is measured and depends on the BW
    4. SINR:
    SINR is the reference value used in the system simulation and can be defined:
    • Wide band SINR
    • SINR for a specific sub-carriers (or for a specific resource elements)
    All measured over the same bandwidth!
    SINR Formula

    RSSP vs RSRQ vs RSSI vs SINR

    Below is a chart that shows what values are considered good and bad for the LTE signal strength values:

    Level of RSRP, RSRQ, SINR Table

    Reference Signals recap: OFDMA Channel Estimation

    In simple terms the Reference Signal (RS) is mapped to Resource Elements (RE). This mapping follows a specific pattern (see to below).
    • So at any point in time the UE will measure all the REs that carry the RS and average the measurements to obtain an RSRP reading.
    • Channel estimation in LTE is based on reference signals (like CPICH functionality in WCDMA)
    • Reference signals position in time domain is fixed (0 and 4 for Type 1 Frame) whereas in frequency domain it depends on the Cell ID
    • In case more than one antenna is used (e.g. MIMO) the Resource elements allocated to reference signals on one antenna are DTX on the other antennas
    • Reference signals are modulated to identify the cell to which they belong

    OFDMA Channel Structure
    OFDMA Channel Structure 1

    Impact of serving cell power to RSRQ:

    Example for noise limited case (no interference): If all resource elements are active and are transmitted with equal power, then
    • RSRQ = N / 12N = -10.8 dB for 1Tx
    • RSRQ = N / 20N = -13 dB for 2Tx taking DTX into account
    (because RSRP is measured over 1 resource element and RSSI per resource block is measured over 12 resource elements).
    Remember that RSSI is only measured at those symbol times during which RS REs are transmitted – We do not have to take into the count DTx!!!
    So, when there is no traffic, and assuming only the reference symbols are transmitted (there are 2 of them within the same symbol of a resource block) from a single Tx antenna then the RSSI is generated by only the 2 reference symbols so the result becomes
    • RSRQ = N / 2N = -3 dB for 1Tx
    • RSRQ = -6dB for 2Tx

    SNR vs. RSRP

    RSRP is measured for a single subcarrier, noisepower for 15KHz= -125.2dBm
    • Noise figure = 7 dB
    • Temperature = 290 K
    SNR Vs RSRP Formula
    Assumption: RSRP doesn’t contain noise power
    SNR Vs RSRP Formula 1

    Power Calculation Example

    Lets try to calculate RSRP, RSSI and RSRQ for one very simple case of one resource block with 12 sub carriers and 0.5 ms in time domain. Let’s assume the power of reference symbols (shown by red square) and power of other symbols carrying other data channels (shown by blue square) is same i.e. 0.021 watt Since RSRP is linear average of downlink reference signal for given channel bandwidth therefore
    RSRP = 10*log (0.021*1000) = 13.2 dBm
    While RSSI is total received wide-band power. Therefore we have to add power of all 12 carriers in the given resource block
    RSSI = 10*log(0.021*1000)+10*log(12) = 24 dBm
    RSRQ is now simple ratio of RSRP to RSSI with N=1
    RSRQ = 10*log(0.021/(12*0.021)) = -10.79 dB

    Power Calculation 1

    Understanding dBm vs dB

    dB is ratio between two power values while dBm is used to express an absolute value of power. So when we mention RSRP and RSSI we shall always use dBm since we are talking about absolute power values but we need to use dB with RSRQ since it is the ratio of RSRP to RSSI
    5. CQI:
    The Channel Quality Indicator (CQI) contains information sent from a UE to the eNode-B to indicate a suitable downlink transmission data rate, i.e., a Modulation and Coding Scheme (MCS) value. CQI is a 4-bit integer and is based on the observed signal-to-interference-plus-noise ratio (SINR) at the UE. The CQI estimation process takes into account the UE capability such as the number of antennas and the type of receiver used for detection. This is important since for the same SINR value the MCS level that can be supported by a UE depends on these various UE capabilities, which needs to be taken into account in order for the eNode-B to select an optimum MCS level for the transmission. The CQI reported values are used by the eNode-B for downlink scheduling and link adaptation, which are important features of LTE.
    In LTE, there are 15 different CQI values randing from 1 to 15 and mapping between CQI and modulcation scheme, transport block size is defined as follows (36.213)

    CQI Modulation Scheme table
    CQI Modulation Scheme table 1
    6. PCI:
    Cell ID sets the physical (PHY) layer Cell ID. This PHY-layer Cell ID determines the Cell ID Group and Cell ID Sector. There are 168 possible Cell ID groups and 3 possible Cell ID sectors; therefore, there are 3 * 168 = 504 possible PHY-layer cell IDs. When Cell ID is set to Auto, the demodulator will automatically detect the Cell ID. When Cell ID is set to Manual, the PHY-layer Cell ID must be specified for successful demodulation.
    The physical layer cell id can be calculated from the following formula:
    PHY-layer Cell ID = 3*(Cell ID Group) + Cell ID Sector
    When Sync Type is set to C-RS, the Cell ID Auto selection will be disabled, and Cell ID must be specified manually. This is because the demodulator needs to know the values of the C-RS sequence to use for synchronization and because Cell ID determines these values. See RS-PRS for more information.
    7. BLER:
    3GPP TS 34.121, F.6.1.1 defines block error ratio (BLER) as follows: "A Block Error Ratio is defined as the ratio of the number of erroneous blocks received to the total number of blocks sent. An erroneous block is defined as a Transport Block, the cyclic redundancy check (CRC) of which is wrong."
    BLER Graph

    8/9. DL/UL Throughput:
    assume a 2×5 MHz LTE system. We first calculate the number of resource elements (RE) in a subframe (a subframe is 1 msec):
    12 Subcarriers x 7 OFDMA Symbols x 25 Resource Blocks x 2 slots = 4,200 REs
    Then we calculate the data rate assuming 64 QAM with no coding (64QAM is the highest modulation for downlink LTE):
    6 bits per 64QAM symbol x 4,200 Res / 1 msec = 25.2 Mbps
    The MIMO data rate is then 2 x 25.2 = 50.4 Mbps. We now have to subtract the overhead related to control signaling such as PDCCH and PBCH channels, reference & synchronization signals, and coding. These are estimated as follows:
    • PDCCH channel can take 1 to 3 symbols out of 14 in a subframe. Assuming that on average it is 2.5 symbols, the amount of overhead due to PDCCH becomes 2.5/14 = 17.86 %.
    • Downlink RS signal uses 4 symbols in every third subcarrier resulting in 16/336 = 4.76% overhead for 2×2 MIMO configuration
    • The other channels (PSS, SSS, PBCH, PCFICH, PHICH) added together amount to ~2.6% of overhead

    The total approximate overhead for the 5 MHz channel is 17.86% + 4.76% + 2.6% = 25.22%.
    The peak data rate is then 0.75 x 50.4 Mbps = 37.8 Mbps.
    Note that the uplink would have lower throughput because the modulation scheme for most device classes is 16QAM in SISO mode only.
    There is another technique to calculate the peak capacity which I include here as well for a 2×20 MHz LTE system with 4×4 MIMO configuration and 64QAM code rate 1:

    Downlink data rate:
    • Pilot overhead (4 Tx antennas) = 14.29%
    • Common channel overhead (adequate to serve 1 UE/subframe) = 10%
    • CP overhead = 6.66%
    • Guard band overhead = 10%

    Downlink data rate = 4 x 6 bps/Hz x 20 MHz x (1-14.29%) x (1-10%) x (1-6.66%) x (1-10%) = 298 Mbps.
    Uplink data rate:
    1 Tx antenna (no MIMO), 64 QAM code rate 1 (Note that typical UEs can support only 16QAM)
    • Pilot overhead = 14.3%
    • Random access overhead = 0.625%
    • CP overhead = 6.66%
    • Guard band overhead = 10%

    Uplink data rate = 1 * 6 bps/Hz x 20 MHz x (1-14.29%) x (1-0.625%) x (1-6.66%) x (1-10%) = 82 Mbps.
    Alternative to these methods, one can refer to 3GPP document 36.213, Table 7.1.7.1-1, Table 7.1.7.2.1-1 and Table 7.1.7.2.2-1 for more accurate calculations of capacity.

    To conclude, the LTE capacity depends on the following:
    • Channel bandwidth
    • Network loading: number of subscribers in a cell which impacts the overhead
    • The configuration & capability of the system: whether it’s 2×2 MIMO, SISO, and the MCS scheme.

    Throughput Troubleshooting

    DL


    DL Flow chart

    UL


    UL Flow chart

    The purpose is to check the performance of Network. We have categories of KPI and numbers of KPI of each category. In the Optimization process we have to check the KPI value to monitor and optimize the radio network performance in order to provide better subscriber quality or to achieve better use of installed network resources . Typically KPI can be categorized into following subcategories:'

    Accessibility KPI
    Are used to measure properly of whether services requested by users can be accessed in given condition, also refers to the quality of being available when users needed. eg. user request to access the network, access the voice call, data call, ......
    📈 Retainability KPI
    Are used to measure how the network keep user's possession or able to hold and provide the services for the users
    📈 Mobility KPI
    Are used to measure the performance of network which can handle the movement of users and still retain the service for the user, such as handover,...
    📈 Integrity KPI
    Are used to measure the character or honesty of network to its user, such as what is the throughput, latency which users were served.
    📈 Availability KPI
    Are used to measure the availability of network, suitable or ready for users to use services.
    📈 Utilization KPI
    Are used to measure the utilization of network, whether the network capacity is reached its resource.

    KPIs for LTE RAN (Radio Access Network)
    LTE KPIINDICATORS
    Accessibility KPI
    • RRC setup success rate
    • ERAB setup success rate
    • Call Setup Success Rate
    Are used to measure properly of whether services requested by users can be accessed in given condition, also refers to the quality of being available when users needed. eg. user request to access the network, access the voice call, data call, ......
    Retainability KPI
    • Call drop rate
    • Service Call drop rate

    Are used to measure how the network keep user's possession or able to hold and provide the services for the users
    Mobility
    KPI
    • Intra-Frequency Handover Out Success Rate
    • Inter-Frequency Handover Out Success Rate
    • Inter-RAT Handover Out Success Rate (LTE to WCDMA)

    Are used to measure the performance of network which can handle the movement of users and still retain the service for the user, such as handover,...
    Integrity
    KPI
    • E-UTRAN IP Throughput
    • IP Throughput in DL
    • E-UTRAN IP Latency

    Are used to measure the character or honesty of network to its user, such as what is the throughput, latency which users were served.
    Availability
    KPI
    • E-UTRAN Cell Availability
      Partial cell availability (node restarts excluded)

    Are used to measure how the network keep user's possession or able to hold and provide the services for the users
    Utilization
    KPI
    • Mean Active Dedicated EPS Bearer Utilization


    Are used to measure the utilization of network, whether the network capacity is reached its resource.


    ACCESSIBILITY KPI:

    ☰ RRC Setup Success Rate
    RRC setup success rate is calculated based on the counter at the eNodeB when the eNodeB received the RRC connection request from UE. Number of RRC connection attempt is collected by the eNodeB to the measurement at point A, and the number of successful RRC connection calculated at point C. Here's an illustration:


    ☰ ERAB setup success rate
    ERAB setup success rate KPI shows the probability of success ERAB to access all services including VoIP in a cell or radio network. KPI is calculated based counter ERAB connection setup attempt (point A) and successful ERAB setup (point B). The explanation is as given in the following illustration:
    ☰ Call Setup Success Rate
    Call Setup Success Rate KPI call setup indicates the probability of success for all service on the cell or radio network. KPI is calculated by multiplying the RRC setup success rate KPI, S1 signaling connection success rate KPI, and ERAB success rate KPI. The table below describes the definition Call Setup Success Rate:


    RETAIN-ABILITY KPI:

    ☰ Call Drop
    VoIP call drop arise when VoIP ERAB release is not normal. Each ERAB associated with QoS information. Here's an illustration of two procedures being done to release ERAB namely: ERAB release indication and the UE context release request:
    MOBILITY KPI:

    ☰ Intra-Frequency Handover Out Success Rate
    Intra-Frequency Handover Success Rate Our KPI shows intra-frequency handover success rate of locall cell or radio network to the intra-frequency neighboring cell or radio network. Intra-frequency HO included in a single cell eNodeB or different eNodeB.
    Intra-frequency HO scenario shown in the figure below:
    No attempt HO calculations at point B. When ENodeB sending RRC connection reconfiguration message to the EU, he will do the handover. ENodeB will count the number of times the HO attempt at the source cell. HO calculation of success is at point C. The HO ENodeB count the number of the source cell when ENodeB receive RRC connection reconfiguration message complete of the EU.
    Here's a scenario intra-frequency handovers inter ENodeB:
    Handover attempt occurs at point B, when the source ENodeB (S-eNodeB) sends RRC connection reconfiguration message to the UE. He decided to conduct inter ENodeB HO. in this KPI, the source and the target cell work on the same frequency. The number of the attempt HO calculated at the source cell. The number of successful HO occurs at point C. During HO, HO amount which success is measured in the cell souce. This measurement appears typing S-eNodeB received a UE context release message from the target eNode B (T-eNodeB), or the UE context release command from the MME, which shows that the UE-eNodeB T has successfully attach at the T-eNodeB.
    The following scenarios illustrate intra frequency B HO - inter ENodeB:
    Following the definition of Intra Frequency Out Handover Success Rate KPI:
    ☰ Inter-RAT Handover Out Success Rate (LTE to WCDMA)
    Inter RAT Handover Out Success rate shows the success rate KPI HO from LTE cell or radio network to a WCDMA cell.
    Here's a scenario out inter RAT handover success rate:
    Inter RAT handover success rate out
    INTEGRITY KPI:

    ☰ E-UTRAN IP Throughput
    A KPI that shows how E-UTRAN impacts the service quality provided to an end-user.
    Payload data volume on IP level per elapsed time unit on the Uu interface. IP Throughput for a single QCI:
    To achieve a throughput measurement that is independent of bursty traffic pattern, it is important to make sure that idle gaps between incoming data is not included in the measurements. That shall be done as considering each burst of data as one sample. ThpVolDl is the volume on IP level and the ThpTimeDl is the time elapsed on Uu for transmission of the volume included in ThpVolDl.
    ☰ E-UTRAN IP Latency
    A measurement that shows how E-UTRAN impacts on the delay experienced by an end-user.
    Time from reception of IP packet to transmission of first packet over the Uu.
    To achieve a delay measurement that is independent of IP data block size only the first packet sent to Uu is measured.
    To find the delay for a certain packet size the IP Throughput measure can be used together with IP Latency (after the first block on the Uu, the remaining time of the packet can be calculated with the IP Throughput measure). 
    T_Lat is defined as the time between receiption of IP packet and the time when the eNodeB transmits the first block to Uu.
    Since services can be mapped towards different kind of E-RABs, the Latency measure shall be available per QoS group.
    AVAILABILITY KPI:

    ☰ E-UTRAN Cell Availability
    E-UTRAN Cell Availability.
    A KPI that shows Availability of E-UTRAN Cell.
    Percentage of time that the cell is considered available.
    As for defining the cell as available, it shall be considered available when the eNodeB can provide E-RAB service in the cell.
    UTILIZATION KPI:



    ☰ Mean Active Dedicated EPS Bearer Utilization
    This KPI describes the ratio of the mean number of active dedicated EPS bearer to the maximum number of active dedicated EPS bearers provided by EPC network, and it is used to evaluate utilization performance of EPC network.
    This KPI is obtained by the mean number of dedicated EPS bearers in active mode divided by the system capacity.
    The mean number of simultaneous online and answered sessions together with maximum number of sessions provided by network can reflect system resource utilization. If the value of this KPI is very high, it indicates system capacity is not enough, and needs to be increased. This KPI is focusing on network view.

    Thursday 29 December 2016


    Posted dateMon, 26th Dec
    LocationSaudi Arabia 

    Job Summary: Radio Network Engineer | TETRA



    Be responsible for network design including Radio Network Planning and Optimization of TETRA network.

    Verify RF related site engineering and drawings, perform system dimensioning, link budget and traffic analysis.

    Prepare network layout/topology for implementation of new or expansion system.

    Assume the lead role, manage and coordinate activities of the TETRA radio team.

    Attend meetings related to projects design, implementation and management.

    Responsible for following, supporting and update all the internal processes and procedures related to Radio Network Engineering.

    Conduct training to radio team/staff to improve knowledge and performance in configuration,

    field installation and maintenance. This includes both hardware and software, and tools.

    Meet with management at regular intervals to report status, progress and issues and suggest optimum resolution.

    To work closely with other groups with Project or Program Responsibilities.

    Drive improvement to the processes and tools use for RF optimization.

    Working with clients, contractors and subcontractor as necessary to meet deployment schedule.

    Responsible for following, supporting and update all the internal processes and procedures related to RNE.



    Qualification:

    Possess at least a Bachelor’s Degree, Engineering (Telecommunication/Electrical/Electronic) or equivalent.



    Experience & Skills:



    Minimum 4-5 years of experience in Radio Network Engineer roles.

    Good knowledge of Telecommunication technologies especially TETRA/TDMA/GSM.

    Good knowledge of Planning in TETRA/TDMA/GSM network.

    Excellent communication, inter-personal skills, teamwork and collaborative abilities.

    Good knowledge on TETRA equipment; TBS, DSC, DWS, Handheld/Mobile Radio, and NMS for

    TETRA (such as NetAct).

    Ability to generate TETRA (RF) engineering related study and/or reports.

    Ability to work with minimal supervision.

    Proven ability to multi-task and organize in order to meet tight deadlines.

    Experience in supervision of data collection, data analysis and reporting.

    Radio access protocols such as GSM, GPRS, UMTS, TETRA.

    Posted dateFri, 23rd Dec
    LocationIndia 

    Hi,

    We have some urgent openings for the following skills:

    Position: Nokia Transmission Lead

    Location: PAN India

    JD:

    We require resource to manage Transmission Network performance based on Nokia Architecture. The task primarily covers to manage operations, Configuration and performance of Transmission networks and Operational Planning based on Nokia Architecture.


    The resource should have around 10-15 Years of experience and should be proficient in understanding, operating, provisioning and managing Performance of Nokia and Ceragon product based Transmission Networks which comprise of Nokia FlexiHopper & Flexi Hybrid MW & NMS. Ceragon SDH1500R/P, IP10, IP20 & Poly view, Cera view and any other relevant EMS/NMS



    Please send CVs to niti.jain@linkquestindia.com. 

    Posted byLCC
    Posted dateFri, 23rd Dec
    LocationPakistan 

    We are looking for an LTE Optimisation Engineer in Lahore

    Minimum 3-4 years of experience,

    Should be Huawei Experienced

    Capable of optimising an already optimised network

    Position is for one Month only

    Joining immediately

    Job TitleLTE Optimization Engineer
    Post Details
    Posted ByLCC
    Start DateImmediate
    Salary
    Email Addressusman_mazhar@lcc.com
    Category
    Job TypeContract
    LocationPakistan
    City or StateLahore


    Posted byDTPL USA


    Posted dateFri, 23rd Dec

    LocationIndia 

    Hands on Experience in Planning & Designing of cellular network



    • Complete knowledge of RAN architecture



    • In depth knowledge of LTE TDD & FDD technology



    • Excellent understanding of Basics of2G, 3G & 4G Cellular Telecom

    • Knowledge of LTE call flows, LTE signaling and protocols.



    • Working experience on planning, processing and optimization tools

    • Good analytical skills for troubleshooting of issues observed during drive test/ walk test



    • Implementation of new features in LTE RAN Network.

    • Multivendor knowledge of LTE RAN network will be advantage.

    • Should possess strong execution & problem solving skills, documentation skills.



    • Should have strong presentation skill to present RF related profile.



    . Candidate should have Green card/H1BO



    As we are looking for Expats, INDIANS please don't apply for this position Please. No. of openings - 4 Positions.



    Its a long term contract job (to start with 6 months with a possible extension of further 6 months)

    Job TitleRF LTE Expert (immeddiate Opening)
    Post Details
    Posted ByDTPL USA
    Start Date1st Oct 2016
    Salary5000 to 1000 USD per month
    Email Addresssharda.kadam@dtplin.com
    Category
    Job TypeContract
    LocationIndia
    City or StateMumbai