The project involved development, integration and testing of a 2G-based Trimode User Terminal (satellite). The scope included developing the speech codec and channel coding for IS-136 specification and integrating it with modem and other modes of the user terminal.

Some of the activities that Aricent worked on included:

• Development of speech codecs and channel codecs for IS-136 functionality.
  
  
• Integration of the above codecs with modem.
  
  
• Testing the Dynamic mode switching between different modes like AMPS and IS-136A and also ensuring that Dynamic switching between ICO and AMPS/IS-136 doesn't happen.
  
  
• Testing the modem performance using standard test equipments and generating a set of baseline curves (BER vs. C/I on various channel conditions) that are validated against simulated baseline curves.
  
  
• Carrying out the HW RF performance after completing bit-exact integration test on the target board. The receiver sensitivity figures were derived by assuming that overall receive chain's noise figure is 5 dB.
  
  
• Aricent was also involved in Design Verification Tests (DVT) to verify individual hardware modules and sub-systems. These included RF Transmitter DVT, Frequency Synthesizer DVT and RF Receiver DVT. A set of exit criteria (which is a collection of DVT parametric results keyed to key design objectives of the boards under test) is established before each hardware design phase is allowed to proceed to the next level.

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The project required the development of a 2.5G-based Base Transceiver system (BTS) to support GPRS/EDGE features. The scope involved porting the existing GSM physical layer functionality onto a new hardware platform and then enhancing the code for GPRS/EGPRS functionality, Simulation, Design, Implementation, Testing, Integration activities (unit testing, integration testing and performance testing including RF), Feature Enhancements based on proprietary performance enhancing algorithms. Additional responsibility included maintaining the Multi-site Configuration Management/Build Management system and correction of some problems reported in previous DSP Software Releases.

Some of the activities that Aricent worked on included:

• Support for Channel Coding for GPRS and EGPRS (MCS1-9)
  
  
• Control firmware (like porting the channel DSP software from Single-core to Dual-core)
  
  
• Enhancement of Hopping Algorithms, Radio Link Measurements (for both GSM and GPRS) and Power Control functionality
  
  
• Support for AMR speech codec (including channel coding functionality)
  
  
• Link Adaptation for (E)GPRS
  
  
• Support for PCU frames in BTS including BTS-PCU Synchronization
  
  
• Interface with other components of BTS (Abis, RF, ASICs, Control Processor)
  
  
• Task Scheduler for DSPs, Inter-core DSP and UC-DSP communication
  
  
• Testing of BTS functionality which included
  
  
  • Layer 1 and Layer 3 testing of BTS
    
    
  • End-to-end system testing (BSC-BTS-MS) as shown in the figure below
    
    
  • Some of the tools used for debugging / testing the BTS sub-system included Nethawk Abis Analyser, Radio Communication Tester (Rhode & Schwarz), Spectrum Analyser, Logic Analyser, Fading Simulator, There was also usage of Emulators and Proprietary test tools for debugging DSP during run-time etc.

The project called for development of a baseband engine (BBE) for 3G-based user terminal. The scope involved developing a reference 'C' code which can be used as a simulation test bench for verifying and validating various algorithms developed for UMTS-FDD based 3G User Terminal. The solution can be used as reference software for porting onto any DSP/FPGA. The Core UMTS-BBE functionality implemented as Channel Coding and Multiplexing (CCM), Spreading Scrambling and Modulation (SSM) and Measurement and Power Control (MPC) libraries.

The CCM library consists of the channel coding modules while the SSM library consists of

• Scrambling Codes (UL/DL) encoding/decoding
  
  
• Spreading (UL/DL) encoding/decoding using OVSF Channelisation codes
  
  
• RRC filter (a=0.22)
  
  
• Channel Estimation (CE) using P-CPICH
  
  
• Multi-finger Rake receiver (DL)
  
  
• Initial Cell Search and Acquisition
  
  
• Support for Compressed Mode (SF/2) and closed-loop diversity
  

HThe baseband engine supports all the mandatory uplink and downlink physical channels - DPDCH/DPCCH, PRACH, P-SCH, S-SCH, P-CPICH, P-CCPCH, S-CCPCH, PICH, AICH etc.

Some of the features of the UMTS BBE (as shown in the figure included:

• Message simulation messages to/from RRC and RLC/MAC to L1.CPHY and PHY messages simulated using parameter files
  
  
• Test Harness Library (THALI) for performance testing of UMTS BBE
  
  
• Debugging features including run-time trace enabling/disabling, useful for capturing and analyzing data during simulation
  
  
• Flexible framework to easily integrate a new Physical Channel into BBE with minimum changes
  
  
• usage of concepts such as Channel Preference Order & Channel Dependencies
  
  
• Reference Solution which can be easily ported into DSP and FPGA
  

The project was for development of an OFDM based WLAN Solution. The scope involved simulation of baseband components (transmitter and receiver), developing the MAC layer and integrating both of them.

Some of the activities involved in development of WLAN based solution included:

• Convolutional Encoder/ Decoder
  
  
• Framing/De-framing, PLCP DATA scrambler & De-scrambler, Block Interleaver/ De-interleaver, Bit Puncturing/ De-puncturing
  
  
• OFDM modulation & Mapping
  
  
• Inverse FFT/ FFT (64 point Radix-4 FFT), Guard Interval Adder/ Remover
  
  
• Transmit Filter
  
  
• Clear Channel Assessment & RSSI processing
  
  
• Symbol & Frame Synchronisation, Carrier recovery and State Transition Machine and clock divider
  
  
• Advanced I & Q signals for various modulation schemes, Arbitrary test vectors with complex, high bit rate signals,
  
  
• Tx & Rx path noise analysis, and BER/FER/PER analysis under simulated environment & channel conditions
  

Aricent also possesses experience in building MAC layer solutions for IEEE 802.11x based LAN. Capabilities exist in designing, developing and testing all the functionalities of the MAC layer and include:

• Authentication Service: Authentication State, Open System Authentication, Shared Key Authentication, De-authentication
  
  
• WEP Privacy Algorithm: WEP Encryption, WEP Decryption, Security Service Management, Optional security functionality
  
  
• Distributed Co-ordination Function: Net Allocation Vector (NAV), Interframe Space & Usage Timings, Random Backoff Procedure, DCF Access Procedure, Recovery Procedures & Retransmission Limits, RTS/CTS Procedures, MAC Level Acknowledgement, Directed MPDU, Broadcast & Multicast MPDU, Duplicate Detection & Recovery
  
  
• Point Co-ordination Function: Maintenance of PCF Structures & Timings, PCFMPDU Transfer to Point Coordinator, PCFMPDU Transfer from Point Coordinator, Overlapping PC Provisions, Polling List
  
  
• Fragmentation & Defragmentation Services
  
  
  
• MAC Data Services: Strictly Ordered Service, Re-orderable Multicast Service
  
  
• Multi-Rate Support: From basic rate to maximum rate
  
  
• Multiple Outstanding MSDU: Multiple Outstanding MSDU Transmission Restrictions
  
  
• Timing Synchronisation: Timing for IBSS and Infrastructure Networks, Beacon Generation, TSF Synchronisation for various PHY modes, Active/ Passive Scanning, Probing Responses and Power Management: STA Power Management Modes, TIM Transmission, AP function during CP and CFP periods, Initialisation of Power Management (IBSS), STA Power State Transmission, Ageing Functions.
  
  
• Association and Reassociation: Association State, AP/STA Association Procedures, AP/STA Reassociation Procedures
  

The project needed development of a VSAT based VoP/FoP system. The scope involved simulation and porting of various VoP/FoP components into the DSP and integrating the same with a control processor and external interfaces (like SLIC/SLAC etc). The solution has been commercially deployed and is being used by a major international communications equipment manufacturer.

Some of the activities that involved Aricent in development of VoP/FoP based system included:

• Implementation / Integration of speech codecs and general telephony algorithms
  
  
  • DTMF generator/detector, tone detector (voiceband), Echo Canceller
    
    
  • G.729, G.729A, G.729B, Flextronics proprietary (4kbps)
    
    
  • Implementation of G3Fax functionality which includes
    
    
    • V.21, V.27ter, V.29 modems, timing/carrier recovery and clock synchronization algorithms etc (simulation and fixed-point porting)
      
      
    • T.30, T.38 protocol engines
      
      
  • Implementation of Control firmware which includes
    
    
    • CP-DSP communication
      
      
    • Dynamic downloading of applications
      
      
    • Debug and health routines, Diagnostics and statistics
      
      
  • Stand-alone System Testing and interoperability testing
    
    
    • Stand-alone system testing with CISCO's Access Servers and Gateways (like 5600, 5300, 2600 etc.), used in end-to-end call testing as shown below
      
      
    • Interoperability testing against a variety of Fax machines,Agilent's TELEGRA and Genoa's FAXLAB test instruments

The project is for development of a video terminal development for Satellite based Packet Network. The scope involved system study/architecture, doing some initial algorithm simulations, and porting of multimedia codecs and integrating the same with stacks/control software running on a control processor.

Some of the activities where Aricent was involved during the development included:

• Simulation, Development and Testing of:
  
  
  • Video Stitching for H.261, H.263, H.264
    
    
  • Voice Activated Video Switching Scheme
    
    
  • Jitter Buffer Management for MCU as well as Terminal
    
    
  • Audio - Video Synchronization for MCU's as well as terminal
    
    
  • Audio Packet Loss Concealment
    
    
  • Echo Cancellation
    
    
  • Evaluation of video codecs wrt quality vs bit-rate for various codecs
    
    
• Testing and integration of Audio and Video Codecs.
  
  
• Implementing RTP Packetization Scheme for Audio and Video Codecs.

Drivers for DSP peripherals and interface between Control Processor and DSP