High Rate Packet Research Articles

Perception-Based Data Reduction for Haptic Force-Feedback Signals Using Velocity-Adaptive Deadbands

In telepresence and teleaction (TPTA) systems, the transmission of haptic signals puts high demands on the applied signal processing and communication procedures. When running a TPTA session across a packet-based communication network (e.g., the Internet), minimizing the end-to-end delay results in packet rates of up to the applied sampling rate of the local control loops at the human system interface and the teleoperator. The perceptual deadband data reduction approach for haptic signals successfully addresses the challenge of high packet rates in networked TPTA systems and satisfies the strict delay constraints. In this paper, we extend the underlying perceptual model of the deadband approach by incorporating psychophysical findings on human force-feedback discrimination during operators' relative hand movements. By applying velocity-dependent perception thresholds to the deadband approach, we observe further improvement in efficiency and performance due to improved adaption to human haptic perception thresholds. The psychophysical experiments conducted reveal improved data reduction performance of our proposed haptic perceptual coding scheme without impairing the user experience. Our results show a high data reduction ability of up to 96% without affecting system transparency or the operator's task performance.

TD-SCDMA Evolution

This article focuses on the evolutional strategies (which can be divided into four phases) from the current commercial time division-synchronous code division multiple access (TD-SCDMA) to the future International Mobile Telecommunications (IMT)Advanced systems. The first evolutional phase is to develop an N-frequency technology to improve capacity and ease network planning of the current TD-SCDMA system. Singleand multicarrier high-speed packet access (HSPA) is specified in the second phase for providing high-rate packet services. Long-term evolution (LTE) technology is introduced in the third phase to provide a similar performance of mobile worldwide interoperability for microwave access (WiMAX). Finally, the fourth phase is to implement time division duplex (TDD)-based IMTAdvanced system, which is one of the alternative standards beyond third-generation (3G) systems. The advanced technologies to enhance spectral efficiency are the critical issues emphasized in all the four phases. The challenges and open issues in the different evolutional phases are identified in this article as well.

What are suspicious VoIP delays?

Voice over IP (VoIP) is unquestionably the most popular real-time service in IP networks today. Recent studies have shown that it is also a suitable carrier for information hiding. Hidden communication may pose security concerns as it can lead to confidential information leakage. In VoIP, RTP (Real-time Transport Protocol) in particular, which provides the means for the successful transport of voice packets through IP networks, is suitable for steganographic purposes. It is characterised by a high packet rate compared to other protocols used in IP telephony, resulting in a potentially high steganographic bandwidth. The modification of an RTP packet stream provides many opportunities for hidden communication as the packets may be delayed, reordered or intentionally lost. In this paper, to enable the detection of steganographic exchanges in VoIP, we examined real RTP traffic traces to answer the questions, what do the normal delays in RTP packet streams look like? and, is it possible to detect the use of known RTP steganographic methods based on this knowledge?

A cooperative PC/network-processor platform for gigabit traffic generation

Evaluating the performance of high-speed networks is a critical task that requires reliable tools to generate traffic workloads at high rates. The current software tools provide poor performance in terms of packets per second and timing/rate accuracy, because of the intrinsic limitations of the PC architecture. This paper proposes a different approach, based on a cooperative PC/NP architecture: an advanced software tool runs on a host PC and instructs the processing engines of an Intel IXP2400 network processor, which take care of the actual traffic generation. This way we keep the high flexibility of PC tools while achieving the high packet rates of hardware solutions. The system is able to generate several traffic models (to date, constant bit rate, Poisson and Poissonian arrival of burst are implemented); however the tool is easily extensible in that any other traffic models can be added through the available APIs. In order to improve the system precision, a time correction mechanism is also introduced. Finally, the capability of manipulating and reproducing an actual trace is provided.

Performance analysis of high rate packet capture on multiprocessor platform

With the continuous improvement of transmission rate, high speed network links require good performance of packet capture. The multiprocessor platform has strong computational capabilities, and brings new chance for high rate packet capture. In this paper, we analyze the performance of common packet capture approaches that are based on general-purpose multiprocessor platform. The analysis contains two aspects: one is the maximum packet capture rate and throughput on multiprocessor platform, the other is central processing unit (CPU) load under the maximum capture rate. By comparing and analyzing the experimental result, we give the maximum packet capture rate and throughput of different capture approaches. Furthermore, we analyze the CPU load which is produced by two capture processes run on the multiprocessor platform simultaneously and make a comparison with the single capture process.

Joint uplink and downlink admission control to both streaming and elastic flows in CDMA/HSDPA systems

TCP-based data flows generate packets and ACKs in two directions, be it in the wireline or wireless networks. In the latter case, packets are typically found in the downlink whereas ACKs are in the uplink. These two links are asymmetric in the case of CDMA-based High Data Rate (HDR) and High-Speed Downlink Packet Access (HSDPA) systems, the uplink being much slower than the downlink and thus, in some cases, restrictive in terms of the achievable throughput of the TCP flow. The aim of this work is to evaluate the performance of such a setting, in the presence of both streaming and elastic traffic, under a dynamic scenario where users arrive at the system and leave it after completion of their service. We specifically quantify the impact of the uplink on the overall performance of TCP and study the model variations as functions of several parameters such as load, file size and radio conditions.

EV-do revision C: Evolution of the cdma2000* data optimized system to higher spectral efficiencies and enhanced services

Wireless packet data services are poised to be a major growth area, as wireless voice services have reached a fair level of maturity. An effort by the 3rd Generation Partnership Project 2 (3GPP2) standards body to continue to develop the successful data-optimized 1x EV-DO high rate packet data (HRPD) 3G system is under way. Alcatel-Lucent along with partners is proposing several novel techniques beyond the state of the art. Some of the key technologies are orthogonal frequency code division multiple access (OFCDMA), multi-carrier as well as wideband transmission, both frequency division duplex (FDD) and time division duplex (TDD) modes, multiple antenna techniques such as space division multiple access (SDMA) and multiple input multiple output (MIMO), interference mitigation techniques, and frequency domain interference cancellation. These are described in detail along with the resulting benefits. The design goals are to provide flexibility, backward compatibility (both loose and strict), a boost in the spectral efficiency and peak rates, a reduction in latency for real-time services, and a reduction in complexity in the base stations (BS) and mobile stations (MS). In this paper, we describe the underlying design philosophy and the associated technologies of 1x EV-DO Revision C with a focus on Alcatel-Lucent's contribution and provide associated performance results. The standard is expected to be completed in 2Q 2007. © 2007 Alcatel-Lucent.

Accurate Channel Estimation Method for Frequency Domain Equalization on cdma2000 High Rate Packet Data System

In order to improve the forward link capacity of cdma2000 HRPD (High Rate Packet Data) or CDMA2000 1xEV-DO, it is significant to overcome multi-path interference. This paper focuses on FDE (Frequency Domain Equalization) with MMSE (Minimum Mean Square Error) criterion. On top of that, backward compatibility with HRPD should be maintained, in other words common channels such as the pilot channel should not be changed. Thus, the PN (Pseudo Noise) spread pilot block without CP (Cyclic Prefix) signals has to be dealt with for FDE. However, this will cause the conventional channel estimation accuracy to deteriorate. In order to improve the estimation accuracy of the conventional method, this paper presents a MRC (Maximal Ratio Combining) spectrum estimator, IPI (Inter-Path Interference) canceller, and path searcher. The results obtained from computer simulations reveal that the proposed method can improve the PER (Packet Error Rate) performance significantly. If compared with Rake combiner and TDE (Time Domain Equalization) with NLMS (Normalized Least Mean Square) scheme, the maximum data rates at a fixed PER of 1% can be increased by 5 to 8 times and 1.25 to 2.67 times, respectively.

High rate packets transmission on ethernet LAN using commodity hardware

We report on measurements performed to test the reliability of high rate data transmission over copper Gigabit Ethernet for the LHCb online system. High reliability of such transmissions will be crucial for the functioning of the software trigger layers of the LHCb experiment, at the CERN's LHC accelerator. The technological challenge in the system implementation consists of handling the expected high data throughput of event fragments using, to a large extent, commodity equipment. We report on performance evaluations (throughput, error rates and frame drop) of the main components involved in data transmission: the Ethernet cable, the PCI bus and the operating system (the latest kernel versions of Linux). Three different platforms have been used.

On acquisition of wideband direct-sequence spread spectrum signals

Very high rate packet data systems such as those based on wideband spread-spectrum (SS) signaling face an important challenge - achieving fast and reliable acquisition to minimize preamble overhead and optimize packet throughput. Such wideband modulation schemes undergo frequency selective fading, implying a very large number of resolved multipath components. Thus, the conventional analyses of serial search acquisition schemes based on simplifying assumptions that are valid in narrow(er) band systems (and are invalid for sufficiently wideband systems) need to be revamped. Also, there is a need to devise new schemes that exploit the presence of multipath components for faster acquisition over simple serial search. Our work provides novel contributions in both these aspects: we analyze serial and random search acquisition schemes and compare their performances in several multipath environments. It is shown that over many typical indoor channels, random search offers significantly lower mean acquisition times

Advantages of harmonized IMS-based charging architecture in different access technologies

Independent standards organizations are currently developing accounting mechanisms such as session-based charging that often require interworking between different networks. A harmonized IP Multimedia Subsystem (IMS)-based charging architecture simplifies interworking. Harmonization provides cost-efficient product development by allowing implementation of common products in networks that are based on different access technologies such as wideband code division multiple access (W-CDMA)-based UMTS <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∗</sup> - and CDMA2000 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∗</sup> -based high rate packet data (HRPD, formerly 1xEVDO). Since IMS allows for a wide variety of services irrespective of access technologies, as new functions are added, IMS provides the flexibility for a rich suite of charging functions and promotes the natural evolution of features with functional forward compatibility. The 3rd Generation Partnership Project (3GPP), the standards organization promoting UMTS, has developed IMS-based architecture for offline and online charging. The 3rd Generation Partnership Project 2 (3GPP2), the standards organization promoting HRPD, has opted to harmonize charging based on 3GPP architecture. This harmonization effort continues as 3GPP and 3GPP2 develop their next releases. More recently the Open Mobile Alliance <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∗</sup> (OMA) has begun identifying all common charging fields and triggers that can be developed in a single plan, thereby eliminating duplication and potential for error. This effort at convergence is in the early stages, and will affect next-generation network evolution. Its success depends on the willingness of the majority of vendors and operators to support its goals [7].

Numerical analysis of packet merge technique: The QoS improvement and the application domain

The packet merge technique combines packets and lowers the packet rate to improve the Quality of Service (QoS) degradation of a network caused by the increase in the delay time and packet losses due to a longer router queue and buffer overflow caused by the high packet rate traffic. However, combining the packets is accompanied by an increase in the waiting delays due to waiting for succeeding packets and transmission delay due to the larger packet size. Therefore, this situation becomes a new source of QoS degradation. There is a trade-off relationship between the improvement by this technique and the delays generated by the technique. Suitable applications and parameter settings are important to improve the QoS. In this paper, we derive the delay time distribution and the packet loss rate of the received packets passing through a network applying this packet merge technique, and describe the characteristics of this technique and the application domain. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(7): 35–48, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/ecja.20253

Radio Resource Management and Power Control for W-CDMA Uplink with High Data Rate Packet Transmission

In wideband code division multiaccess (W-CDMA) uplink, immediate accommodation of high data rate packet causes power control error and makes active users' signal quality deteriorate in a beginning of a frame. To avoid the deterioration, we propose a new radio resource management (RRM) which accommodates high data rate traffic gradually in several frames. The proposed RRM reduces the signal quality deterioration in the beginning of the frame. We also propose an effective power control scheme, where a power increase command is sent to all users before a new high dala rate packet is transmitted. Simulation results show that joint utilization of the proposed two methods is effective to keep signal quality good for all users.

NETWORK TRAFFIC REDUCTION IN HAPTIC TELEPRESENCE SYSTEMS BY DEADBAND CONTROL

Current haptic (force feedback) telepresence systems operated over a communication network as, e.g. the Internet, require high packet rates for the transmission of the command and sensor signals. A novel approach to reduce the network traffic by means of deadband control is proposed. Data packets are only sent if the sampled signal changes more than a given threshold value. Passivity based reconstruction methods are introduced to reconstruct the untransmitted values at the receiver guaranteeing stability of the overall system. Experiments show that a packet rate reduction of up to 87% is achieved without impairing transparency.

A genetic approach for downlink packet scheduling in HSDPA system

High speed downlink packet access (HSDPA) system currently under development in 3rd generation partnership project (3GPP) [1] employs number of parallel shared channels and adaptive modulation and coding scheme (MCS) to enable a high rate packet data transfer from base station (Node-B) to user equipment (UE). To decide how to share the available radio channel capacity amongst the active UEs, a packet scheduling and channel assignment algorithms are employed at Node B. Packet scheduling techniques such as max carrier to interference ratio (C/I) or round robin (RR) fails to take into account all the aspects of the quality of service (QoS) provisioning. In this paper, the fundamentals genetic algorithms and conventional wireless scheduling techniques are combined and the weaknesses of the existing known techniques are exploited to propose a novel hybrid genetic packet scheduler (HGPS) for the HSDPA system. A combination of random and intelligent diversity of population and comparative nature of the selection process of genetic engine contribute to its robustness. The proposed HGPS outperforms Max C/I packet scheduler in terms of total delivered throughput within low delay thresholds. Unlike conventional packet scheduling technique HGPS does not rely only on the current or past status of the scheduling process. By treating the possible solutions as points in a search space, the proposed HGPS through a genetically guided search visits and examines the possible solutions and estimates the impact of each these solution on overall performance of system in terms of fairness, throughput or QoS without actually performing a transmission. Subsequently, the solution that achieves the best estimated overall performance is chosen for the actual transmission. By means of computer simulation, performance of the HGPS algorithm is characterized in Rayleigh fading and shadowing radio channel conditions. The impact of imperfect reporting on the performance of HSDPA system is evaluated. We examine the joint impact of reporting latency, imperfect channel estimation and the corruption of reports in the feedback channel on the performance. It is shown that the proposed class of intelligent parallel random schedulers is highly robust against the imperfect reports from UEs.

Optimum Packet Data Transmission in Cellular Multirate CDMA Systems With Rate-Based Slot Allocation

High-rate packet transmission is realized for the downlink in cellular multirate code-division multiple-access systems using multicode concatenated signaling, combined with iterative detection and self-interference cancellation. Since an optimum packet transmission is to allocate the maximum allowable rate to the user with the best received signal-to-interference-plus-noise ratio (SINR), a problem with fairness arises, in the sense that only a very small number of users receive at or near the maximum allowable rate, and the rest of the users do not receive at all. To overcome this, a new soft multimodal fairness control is proposed to adjust the latency (or waiting time) between two extreme values. Throughput is analyzed by deriving the probability distribution of the rate allocation, which is based on the maximum received SINR in a slot. For this, statistics on the SINRs are jointly characterized under three-sector cell structure because of their mutual correlation. Traffic variations are also taken into account to formulate the statistics under two algorithms for adaptive base station selection. It is shown that high-rate transmission can be achieved by a substantial reduction in in-cell interference, and the tradeoff between throughput and fairness can be met by the fairness control.

IBM PowerNP network processor: Hardware, software, and applications

Deep packet processing is migrating to the edges of service provider networks to simplify and speed up core functions. On the other hand, the cores of such networks are migrating to the switching of high-speed traffic aggregates. As a result, more services will have to be performed at the edges, on behalf of both the core and the end users. Associated network equipment will therefore require high flexibility to support evolving high-level services as well as extraordinary performance to deal with the high packet rates. Whereas, in the past, network equipment was based either on general-purpose processors (GPPs) or application-specific integrated circuits (ASICs), favoring flexibility over speed or vice versa, the network processor approach achieves both flexibility and performance. The key advantage of network processors is that hardware-level performance is complemented by flexible software architecture. This paper provides an overview of the IBM PowerNPTM NP4GS3 network processor and how it addresses these issues. Its hardware and software design characteristics and its comprehensive base operating software make it well suited for a wide range of networking applications.

Fundamental architectural considerations for network processors

Network processors (NPs) are programmable devices with special architectural features that are optimized to perform packet-processing functions. They have emerged to cope with the ever-changing networking applications that are becoming increasingly complex. NPs are expected to become the silicon core of network equipments that require a high degree of flexibility to support evolving network services at extraordinary performance with high packet rates. In this paper, we present and examine various NP architectural aspects. We describe and compare NP design characteristics and analyze their implications on the ease of programming.

Scenario driven evaluation and interference mitigation proposals for Bluetooth and high data rate Bluetooth enabled consumer electronic devices

Previous research has focussed on residential coverage and achievable data rates using the Bluetooth personal area network (PAN) standard. To meet the bit rate needs of future consumer electronics devices, M-PSK modulation schemes have been proposed as likely candidates for high data rate extensions to Bluetooth. This paper investigates the effects of interference occurring between high data rate time-bounded and non-time-bounded Bluetooth enabled consumer electronic devices. Frequency hopping selection kernels for both the 79-hop and the 23-hop systems in Bluetooth were implemented in software. Using this model, collision statistics were obtained between a wanted Bluetooth user (in a piconet) and interferers (Bluetooth users in different piconets) operating under typical scenarios that were constructed within the test environment. These scenarios featured piconets operating in an office environment in both synchronous and asynchronous modes and with typical up and downlink loading factors. A detailed link level physical layer simulation was used to obtain packet error rate performance based on the collision statistics obtained. Finally, a state-of-the-art indoor space-time propagation modelling tool was used to analyse the data throughput performance capabilities for Bluetooth data medium (DM) rate and data high (DH) rate packets. Results highlight a clear need to mitigate interference by employing synchronous communication in future Bluetooth evolution networks.

Clustered OFDM with channel estimation for high rate wireless data

Clustered OFDM can provide in-band diversity gain for wideband wireless communication systems. It is a promising technique for high rate packet data access over wideband mobile wireless channels. Due to the smaller size of each cluster for clustered OFDM than for classical (nonclustered) OFDM, edge effects can be very large. In this letter, we present new transforms for channel estimators in clustered OFDM systems. The new transforms are independent of the channel delay profiles and can effectively mitigate the edge effects. It is shown by computer simulation that the performance of clustered OFDM with the estimator using the new transforms is very close to the performance with the optimum estimator that is determined by the individual channel delay profile. Furthermore, clustered OFDM with the new estimator is almost as good as classical OFDM with transmit diversity.