The Experts below are selected from a list of 7404 Experts worldwide ranked by ideXlab platform

Milica Stojanovic - One of the best experts on this subject based on the ideXlab platform.

  • on coding for delay network coding for Time Division Duplexing
    IEEE Transactions on Information Theory, 2012
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    In networks with large latency, feedback about received packets may lag considerably the transmission of the original packets, limiting the feedback's usefulness. Moreover, Time duplex constraints may entail that receiving feedback may be costly. In this work, we consider tailoring feedback and coding jointly in such settings to reduce the expected delay for successful in order reception of packets. We find that, in certain applications, judicious choices provide results that are close to those that would be obtained with a full-duplex system. We study two cases of data transmission: one-to-all broadcast and all-to-all broadcast. We also analyze important practical considerations weighing the trade off between performance and complexity in applications that rely on random linear network coding. Finally, we study the problem of transmission of information under the large latency and Time Duplexing constraints in the presence of random packet arrivals. In particular, we analyze the problem of using a batch by batch approach and an online network coding approach with Poisson arrivals. We present numerical results to illustrate the performance under a variety of scenarios and show the benefits of the proposed schemes as compared to typical ARQ and scheduling schemes.

  • online network coding for Time Division Duplexing
    Global Communications Conference, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We study an online random linear network coding approach for Time Division Duplexing (TDD) channels under Poisson arrivals. We model the system as a bulk-service queue with variable bulk size and with feedback, i.e., when a set of packets are serviced at a given Time, they might be reintroduced to the queue to form part of the next service batch. We show that there is an optimal number of coded data packets that the sender should transmit back-to-back before stopping to wait for an acknowledgement from the receiver. This number depends on the latency, probability of packet erasure, degrees of freedom at the receiver, the size of the coding window, and the arrival rate of the Poisson process. Random network coding is performed across a moving window of packets that depends on the packets in the queue, design constraints on the window size, and the feedback sent from the receiver. We study the mean Time between generating a packet at the source and it being ``seen", but not necessarily decoded, at the receiver. We also analyze the mean Time between a decoding event and the next, defined as the decoding of all the packets that have been previously ``seen" and those packets involved in the current window of packets. Inherently, a decoding event implies an in-order decoding of a batch of data packets. We present numerical results illustrating the trade-off between mean delay and mean Time between decoding events.

  • systematic network coding for Time Division Duplexing
    International Symposium on Information Theory, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We present a systematic network coding approach for Time-Division Duplexing channels. In particular, we study the case of a node transmitting to a single receiver. We show that the use of systematic network coding using XORs can provide the same or close to the same performance in terms of completion Time as a random linear network coding scheme that uses a large field size, with the added advantage of requiring fewer and simpler operations during the decoding process. We show that the average computation required to decode using systematic network coding in an erasure channel grows as O(M3Pe3), where M is the number of original packets being coded together, and Pe is the packet erasure probability. This means that systematic network coding requires Pe−3 Times fewer operations on average than random linear network coding with the same field size.

  • ISIT - Systematic network coding for Time-Division Duplexing
    2010 IEEE International Symposium on Information Theory, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We present a systematic network coding approach for Time-Division Duplexing channels. In particular, we study the case of a node transmitting to a single receiver. We show that the use of systematic network coding using XORs can provide the same or close to the same performance in terms of completion Time as a random linear network coding scheme that uses a large field size, with the added advantage of requiring fewer and simpler operations during the decoding process. We show that the average computation required to decode using systematic network coding in an erasure channel grows as O(M3Pe3), where M is the number of original packets being coded together, and Pe is the packet erasure probability. This means that systematic network coding requires Pe−3 Times fewer operations on average than random linear network coding with the same field size.

  • GLOBECOM - Online Network Coding for Time-Division Duplexing
    2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We study an online random linear network coding approach for Time Division Duplexing (TDD) channels under Poisson arrivals. We model the system as a bulk-service queue with variable bulk size and with feedback, i.e., when a set of packets are serviced at a given Time, they might be reintroduced to the queue to form part of the next service batch. We show that there is an optimal number of coded data packets that the sender should transmit back-to-back before stopping to wait for an acknowledgement from the receiver. This number depends on the latency, probability of packet erasure, degrees of freedom at the receiver, the size of the coding window, and the arrival rate of the Poisson process. Random network coding is performed across a moving window of packets that depends on the packets in the queue, design constraints on the window size, and the feedback sent from the receiver. We study the mean Time between generating a packet at the source and it being ``seen", but not necessarily decoded, at the receiver. We also analyze the mean Time between a decoding event and the next, defined as the decoding of all the packets that have been previously ``seen" and those packets involved in the current window of packets. Inherently, a decoding event implies an in-order decoding of a batch of data packets. We present numerical results illustrating the trade-off between mean delay and mean Time between decoding events.

Daniel E Lucani - One of the best experts on this subject based on the ideXlab platform.

  • on coding for delay network coding for Time Division Duplexing
    IEEE Transactions on Information Theory, 2012
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    In networks with large latency, feedback about received packets may lag considerably the transmission of the original packets, limiting the feedback's usefulness. Moreover, Time duplex constraints may entail that receiving feedback may be costly. In this work, we consider tailoring feedback and coding jointly in such settings to reduce the expected delay for successful in order reception of packets. We find that, in certain applications, judicious choices provide results that are close to those that would be obtained with a full-duplex system. We study two cases of data transmission: one-to-all broadcast and all-to-all broadcast. We also analyze important practical considerations weighing the trade off between performance and complexity in applications that rely on random linear network coding. Finally, we study the problem of transmission of information under the large latency and Time Duplexing constraints in the presence of random packet arrivals. In particular, we analyze the problem of using a batch by batch approach and an online network coding approach with Poisson arrivals. We present numerical results to illustrate the performance under a variety of scenarios and show the benefits of the proposed schemes as compared to typical ARQ and scheduling schemes.

  • online network coding for Time Division Duplexing
    Global Communications Conference, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We study an online random linear network coding approach for Time Division Duplexing (TDD) channels under Poisson arrivals. We model the system as a bulk-service queue with variable bulk size and with feedback, i.e., when a set of packets are serviced at a given Time, they might be reintroduced to the queue to form part of the next service batch. We show that there is an optimal number of coded data packets that the sender should transmit back-to-back before stopping to wait for an acknowledgement from the receiver. This number depends on the latency, probability of packet erasure, degrees of freedom at the receiver, the size of the coding window, and the arrival rate of the Poisson process. Random network coding is performed across a moving window of packets that depends on the packets in the queue, design constraints on the window size, and the feedback sent from the receiver. We study the mean Time between generating a packet at the source and it being ``seen", but not necessarily decoded, at the receiver. We also analyze the mean Time between a decoding event and the next, defined as the decoding of all the packets that have been previously ``seen" and those packets involved in the current window of packets. Inherently, a decoding event implies an in-order decoding of a batch of data packets. We present numerical results illustrating the trade-off between mean delay and mean Time between decoding events.

  • systematic network coding for Time Division Duplexing
    International Symposium on Information Theory, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We present a systematic network coding approach for Time-Division Duplexing channels. In particular, we study the case of a node transmitting to a single receiver. We show that the use of systematic network coding using XORs can provide the same or close to the same performance in terms of completion Time as a random linear network coding scheme that uses a large field size, with the added advantage of requiring fewer and simpler operations during the decoding process. We show that the average computation required to decode using systematic network coding in an erasure channel grows as O(M3Pe3), where M is the number of original packets being coded together, and Pe is the packet erasure probability. This means that systematic network coding requires Pe−3 Times fewer operations on average than random linear network coding with the same field size.

  • ISIT - Systematic network coding for Time-Division Duplexing
    2010 IEEE International Symposium on Information Theory, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We present a systematic network coding approach for Time-Division Duplexing channels. In particular, we study the case of a node transmitting to a single receiver. We show that the use of systematic network coding using XORs can provide the same or close to the same performance in terms of completion Time as a random linear network coding scheme that uses a large field size, with the added advantage of requiring fewer and simpler operations during the decoding process. We show that the average computation required to decode using systematic network coding in an erasure channel grows as O(M3Pe3), where M is the number of original packets being coded together, and Pe is the packet erasure probability. This means that systematic network coding requires Pe−3 Times fewer operations on average than random linear network coding with the same field size.

  • GLOBECOM - Online Network Coding for Time-Division Duplexing
    2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We study an online random linear network coding approach for Time Division Duplexing (TDD) channels under Poisson arrivals. We model the system as a bulk-service queue with variable bulk size and with feedback, i.e., when a set of packets are serviced at a given Time, they might be reintroduced to the queue to form part of the next service batch. We show that there is an optimal number of coded data packets that the sender should transmit back-to-back before stopping to wait for an acknowledgement from the receiver. This number depends on the latency, probability of packet erasure, degrees of freedom at the receiver, the size of the coding window, and the arrival rate of the Poisson process. Random network coding is performed across a moving window of packets that depends on the packets in the queue, design constraints on the window size, and the feedback sent from the receiver. We study the mean Time between generating a packet at the source and it being ``seen", but not necessarily decoded, at the receiver. We also analyze the mean Time between a decoding event and the next, defined as the decoding of all the packets that have been previously ``seen" and those packets involved in the current window of packets. Inherently, a decoding event implies an in-order decoding of a batch of data packets. We present numerical results illustrating the trade-off between mean delay and mean Time between decoding events.

Muriel Medard - One of the best experts on this subject based on the ideXlab platform.

  • on coding for delay network coding for Time Division Duplexing
    IEEE Transactions on Information Theory, 2012
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    In networks with large latency, feedback about received packets may lag considerably the transmission of the original packets, limiting the feedback's usefulness. Moreover, Time duplex constraints may entail that receiving feedback may be costly. In this work, we consider tailoring feedback and coding jointly in such settings to reduce the expected delay for successful in order reception of packets. We find that, in certain applications, judicious choices provide results that are close to those that would be obtained with a full-duplex system. We study two cases of data transmission: one-to-all broadcast and all-to-all broadcast. We also analyze important practical considerations weighing the trade off between performance and complexity in applications that rely on random linear network coding. Finally, we study the problem of transmission of information under the large latency and Time Duplexing constraints in the presence of random packet arrivals. In particular, we analyze the problem of using a batch by batch approach and an online network coding approach with Poisson arrivals. We present numerical results to illustrate the performance under a variety of scenarios and show the benefits of the proposed schemes as compared to typical ARQ and scheduling schemes.

  • online network coding for Time Division Duplexing
    Global Communications Conference, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We study an online random linear network coding approach for Time Division Duplexing (TDD) channels under Poisson arrivals. We model the system as a bulk-service queue with variable bulk size and with feedback, i.e., when a set of packets are serviced at a given Time, they might be reintroduced to the queue to form part of the next service batch. We show that there is an optimal number of coded data packets that the sender should transmit back-to-back before stopping to wait for an acknowledgement from the receiver. This number depends on the latency, probability of packet erasure, degrees of freedom at the receiver, the size of the coding window, and the arrival rate of the Poisson process. Random network coding is performed across a moving window of packets that depends on the packets in the queue, design constraints on the window size, and the feedback sent from the receiver. We study the mean Time between generating a packet at the source and it being ``seen", but not necessarily decoded, at the receiver. We also analyze the mean Time between a decoding event and the next, defined as the decoding of all the packets that have been previously ``seen" and those packets involved in the current window of packets. Inherently, a decoding event implies an in-order decoding of a batch of data packets. We present numerical results illustrating the trade-off between mean delay and mean Time between decoding events.

  • systematic network coding for Time Division Duplexing
    International Symposium on Information Theory, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We present a systematic network coding approach for Time-Division Duplexing channels. In particular, we study the case of a node transmitting to a single receiver. We show that the use of systematic network coding using XORs can provide the same or close to the same performance in terms of completion Time as a random linear network coding scheme that uses a large field size, with the added advantage of requiring fewer and simpler operations during the decoding process. We show that the average computation required to decode using systematic network coding in an erasure channel grows as O(M3Pe3), where M is the number of original packets being coded together, and Pe is the packet erasure probability. This means that systematic network coding requires Pe−3 Times fewer operations on average than random linear network coding with the same field size.

  • ISIT - Systematic network coding for Time-Division Duplexing
    2010 IEEE International Symposium on Information Theory, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We present a systematic network coding approach for Time-Division Duplexing channels. In particular, we study the case of a node transmitting to a single receiver. We show that the use of systematic network coding using XORs can provide the same or close to the same performance in terms of completion Time as a random linear network coding scheme that uses a large field size, with the added advantage of requiring fewer and simpler operations during the decoding process. We show that the average computation required to decode using systematic network coding in an erasure channel grows as O(M3Pe3), where M is the number of original packets being coded together, and Pe is the packet erasure probability. This means that systematic network coding requires Pe−3 Times fewer operations on average than random linear network coding with the same field size.

  • GLOBECOM - Online Network Coding for Time-Division Duplexing
    2010 IEEE Global Telecommunications Conference GLOBECOM 2010, 2010
    Co-Authors: Daniel E Lucani, Muriel Medard, Milica Stojanovic
    Abstract:

    We study an online random linear network coding approach for Time Division Duplexing (TDD) channels under Poisson arrivals. We model the system as a bulk-service queue with variable bulk size and with feedback, i.e., when a set of packets are serviced at a given Time, they might be reintroduced to the queue to form part of the next service batch. We show that there is an optimal number of coded data packets that the sender should transmit back-to-back before stopping to wait for an acknowledgement from the receiver. This number depends on the latency, probability of packet erasure, degrees of freedom at the receiver, the size of the coding window, and the arrival rate of the Poisson process. Random network coding is performed across a moving window of packets that depends on the packets in the queue, design constraints on the window size, and the feedback sent from the receiver. We study the mean Time between generating a packet at the source and it being ``seen", but not necessarily decoded, at the receiver. We also analyze the mean Time between a decoding event and the next, defined as the decoding of all the packets that have been previously ``seen" and those packets involved in the current window of packets. Inherently, a decoding event implies an in-order decoding of a batch of data packets. We present numerical results illustrating the trade-off between mean delay and mean Time between decoding events.

C.-e.w. Sundberg - One of the best experts on this subject based on the ideXlab platform.

  • Shared Time-Division Duplexing (STDD): impact of runlengths of dropped packets and fast-speech activity detection
    IEEE Transactions on Vehicular Technology, 1998
    Co-Authors: H.c. Papadopoulos, C.-e.w. Sundberg
    Abstract:

    Shared Time-Division Duplexing (STDD) is a proposed high-quality low-delay multiple-access technique for microcellular systems. By sharing Time slots in both directions of transmission, it provides a considerable increase in capacity over Time-Division systems with speech activity detection (SAD) with relatively few users per carrier frequency. We investigate the temporal robustness of Time-Division multiple access (TDMA) with TDD/SAD and STDD. We specifically consider the statistics of the runlength of dropped packets for each scheme and show that although STDD is superior to TDMA/TDD/SAD when both systems are operating at full capacity, both systems suffer from long periods of dropped packets. We introduce circular interleaving as a method of reducing the average runlength of dropped packets. Fast SAD (FSAD) is also considered. We obtain a novel model that describes (FSAD) speech for a pair of users by merging two existing models: one for (slow) SAD on-off speech for a pair of users and one describing FSAD speech of a single user. It is concluded based on this model that FSAD results in a considerable increase in the capacity over systems with slow SAD as well as in shorter average runlengths of dropped packets. A number of numerical results are included, especially for the short frame length of 2 ms. We note that FSAD yields a further capacity gain of about 20% beyond that of STDD with slow SAD.

  • Reduction of mixed cochannel interference in microcellular shared Time-Division Duplexing (STDD) systems
    IEEE Transactions on Vehicular Technology, 1998
    Co-Authors: H.c. Papadopoulos, C.-e.w. Sundberg
    Abstract:

    Shared Time-Division Duplexing (STDD) is an attractive candidate for high-quality low-delay multiple access in microcellular systems. STDD provides a considerable increase in capacity over conventional Time-Division systems with conventional speech activity detection (SAD). By sharing Time slots in both directions of transmission, large statistical multiplexing gains are obtained, even with a moderate number of users per carrier. We show by means of theory that STDD is superior to conventional Time-Division multiple access (TDMA) as well as TDMA/TDD/SAD in terms of capacity. We furthermore demonstrate how a type of mixed cochannel interference particular to STDD can be reduced or almost eliminated by means of directional antennas at the base stations for both reception and transmission, combined with appropriate organization of the Time burst. The concept of partially shared TDD (PSTDD) is also introduced, and the tradeoff between capacity gains by means of statistical multiplexing and packets dropped due to interference is studied by means of analysis. To illustrate the introduced concepts and methodology of evaluation, a number of numerical results are given for a frame length of 2 ms. Statistical multiplexing gains of the order of 100% over TDMA are obtained with 40 speech slots per frame and a packet dropping rate of 0.1%.

  • Shared Time Division Duplexing: an approach to low-delay high-quality wireless digital speech communications
    IEEE Transactions on Vehicular Technology, 1994
    Co-Authors: Wai-choong Wong, C.-e.w. Sundberg, N. Seshadri
    Abstract:

    Various strategies to provide low-delay high-quality digital speech communications in a high-capacity wireless network are examined. Various multiple access schemes based on Time-Division and packet reservation are compared in terms of their statistical multiplexing capabilities, sensitivity to speech packet dropping, delay, robustness to lossy packet environments, and overhead efficiency. In particular, a low-delay multiple access scheme, called shared Time-Division Duplexing (STDD) is proposed. This scheme allows both the uplink and downlink traffic to share a common channel, thereby achieving high statistical multiplexing gain even with a low population of simultaneous conversations. The authors also propose a choice of low delay, high quality speech coding and digital modulation systems based on adaptive DPCM, with QDPSK or pseudo-analog transmission (skewed DPSK), for use in conjunction with the STDD multiple access protocol. The choice of the alternative systems depends on required end-to-end delay, recovered speech quality and bandwidth efficiency. Typically, with a total capacity of 1 MBaud, 2 ms frame and 8 kBaud speech coding rate, low delay STDD is able to support 48 pairs of users compared to 38, 35, and 16 for TDMA with speech activity detection, basic TDMA and PRMA respectively. This corresponds to respective gains of 26%, 37% and 200%. >

  • Shared Time Division Duplexing
    Proceedings of ICCS '94, 1
    Co-Authors: Wai-choong Wong, C.-e.w. Sundberg, N. Seshadri
    Abstract:

    Various multiple access schemes based on Time-Division and packet reservation are compared in terms of their statistical multiplexing capabilities, sensitivity to speech packet dropping, delay, robustness to lossy packet environments, and overhead efficiency. In particular, the authors propose a low-delay multiple access scheme, called shared Time-Division Duplexing (STDD), which allows both the uplink and downlink traffic to share a common channel, thereby achieving high statistical multiplexing gain even with a low population of simultaneous conversations. Typically with a total capacity of 1 Mbaud, 2 ms frame and 8 kbaud speech rate, low delay STDD is able to support 48 pairs of users compared to 38, 35 and 16 for TDMA with speech activity detection, basic TDMA and PRMA respectively. This corresponds to respective gains of 26%, 37% and 200%. >

  • Shared Time Division Duplexing (STDD) with fast speech activity detection
    Proceedings of ICC SUPERCOMM '96 - International Conference on Communications, 1
    Co-Authors: H.c. Papadopoulos, C.-e.w. Sundberg
    Abstract:

    Motivated by a desire to provide low delay, high quality digital speech communications in a high capacity wireless network, an access method was introduced to achieve these requirements. Such wireless systems are primarily targeted for indoor environments, as well as outdoor microcell environments. We concentrate our efforts on Time Division multiple access (TDMA) systems with Time Division Duplexing (TDD). Shared Time Division Duplexing (STDD), provides a considerable increase in capacity over the conventional Time Division systems with speech activity detection (SAD) even with a moderate number of users per carrier. The key idea in STDD is sharing Time slots in both directions of transmission. Fast speech activity detection (FSAD) is considered. We obtain a novel model that describes (FSAD) speech for a pair of users, by merging two existing models, one for (slow) SAD on-off speech for a pair of users, and one describing FSAD speech of a single user. It is concluded, based on this model, that the use of FSAD results in an increase of approximately 20% in capacity over systems with slow speech activity detection, as well as in much shorter runlengths of dropped packets. Numerical results are included for a short frame length of 2 ms.

Klaus I. Pedersen - One of the best experts on this subject based on the ideXlab platform.

  • cross link interference suppression by orthogonal projector for 5g dynamic tdd urllc systems
    arXiv: Signal Processing, 2020
    Co-Authors: Ali A. Esswie, Klaus I. Pedersen
    Abstract:

    Dynamic Time Division Duplexing (TDD) is envisioned as a vital transmission technology of the 5G new radio, due to its reciprocal propagation characteristics. However, the potential cross-link interference (CLI) imposes a fundamental limitation against the feasibility of the ultra-reliable and low latency communications (URLLC) in dynamic-TDD systems. In this work, we propose a near-optimal and complexity-efficient CLI suppression scheme using orthogonal spatial projection, while the signaling overhead is limited to B-bit, over the back-haul links. Compared to the state-of-the-art dynamic-TDD studies, proposed solution offers a significant improvement of the URLLC outage latency, e.g., -199% reduction, while boosting the achievable capacity per the URLLC packet by +156%.

  • semi static radio frame configuration for urllc deployments in 5g macro tdd networks
    arXiv: Signal Processing, 2020
    Co-Authors: Ali A. Esswie, Klaus I. Pedersen, Preben Mogensen
    Abstract:

    Dynamic Time Division Duplexing (TDD) is one of the major novelties of the 5G new radio standard. It notably improves the network resource utilization with sporadic directional packet arrivals. Although, the feasibility of the ultra-reliable and low-latency communications (URLLC) within such deployments is critically challenged, mainly due to the cross-link interference (CLI). In this work, we propose a semi-static and computationally-efficient TDD radio frame adaptation algorithm for 5G macro deployments. Particularly, we first identify the quasi-static variance of the cross-cell traffic buffering performance, with various CLI co-existence conditions. Accordingly, a common radio frame pattern is dynamically estimated based on the filtered multi-cell traffic statistics. Our system-level simulation results show that the proposed solution achieves a highly improved URLLC outage performance, i.e., offering 40% reduction gain of the achievable URLLC outage latency compared to perfect static-TDD, and approaching the optimal interference-free flexible-TDD case; though, with a significantly lower control overhead size.

  • On the Ultra-Reliable and Low-Latency Communications in Flexible TDD/FDD 5G Networks
    arXiv: Signal Processing, 2019
    Co-Authors: Ali A. Esswie, Klaus I. Pedersen
    Abstract:

    The ultra-reliable and low-latency communication (URLLC) is the key driver of the current 5G new radio standardization. URLLC encompasses sporadic and small-payload transmissions that should be delivered within extremely tight radio latency and reliability bounds, i.e., a radio latency of 1 ms with 99.999% success probability. However, such URLLC targets are further challenging in the 5G dynamic Time Division Duplexing (TDD) systems, due to the switching between the uplink and downlink transmission opportunities and the additional inter-cell cross-link interference (CLI). This paper presents a system level analysis of the URLLC outage performance within the 5G new radio flexible TDD systems. Specifically, we study the feasibility of the URLLC outage targets compared to the case with the 5G frequency Division Duplexing (FDD), and with numerous 5G design variants. The presented results therefore offer valuable observations on the URLLC outage performance in such deployments, and hence, introducing the state-of-the-art flexible-FDD technology.

  • VTC Spring - Inter-Cell Radio Frame Coordination Scheme Based on Sliding Codebook for 5G TDD Systems
    2019 IEEE 89th Vehicular Technology Conference (VTC2019-Spring), 2019
    Co-Authors: Ali A. Esswie, Klaus I. Pedersen
    Abstract:

    The fifth generation (5G) of the wireless communication networks supports wide diversity of service classes, leading to a highly dynamic uplink (UL) and downlink (DL) traffic asymmetry. Thus, dynamic Time Division Duplexing (TDD) technology has become of a significant importance, due to its radio frame flexibility. However, fully dynamic TDD systems suffer from potentially severe inter-cell cross link interference (CLI). In this paper, we propose a novel inter-cell radio frame coordination (RFC) scheme based on sliding codebook for fully dynamic TDD 5G networks. Proposed coordination scheme simultaneously addresses two optimization objectives of minimizing the average CLI while reliably maximizing the achievable DL/UL capacity, by virtually extending the RFC degrees of freedom through a sliding phase-offset RFC codebook design. Compared to the state-of-the-art TDD studies, the proposed scheme shows significantly improved ergodic capacity, i.e., at least 140% gain under both the TCP and UDP protocols, and with much less signaling overhead, limited to B-bit. The paper offers valuable insights about how to most efficiently pre-mitigate potential CLI in Macro TDD systems.

  • Quasi-Dynamic Frame Coordination for Ultra-Reliability and Low-Latency in 5G TDD Systems
    2019 IEEE International Conference on Communications Workshops (ICC Workshops), 2019
    Co-Authors: Ali A. Esswie, Klaus I. Pedersen, Preben Elgaard Mogensen
    Abstract:

    The fifth generation (5G) mobile technology features the ultra-reliable and low-latency communications (URLLC) as a major service class. URLLC applications demand a tight radio latency with extreme link reliability. In 5G dynamic Time Division Duplexing (TDD) systems, URLLC requirements become further challenging to achieve due to the severe and fastvarying cross link interference (CLI) and the switching Time of the radio frame configurations (RFCs). In this work, we propose a quasi-dynamic inter-cell frame coordination algorithm using hybrid frame design and a cyclic-offset-based RFC code-book. The proposed solution adaptively updates the RFCs in Time such that both the average CLI and the user-centric radio latency are minimized. Compared to state-of-the-art dynamic TDD studies, the proposed scheme shows a significant improvement in the URLLC outage latency, i.e. ~ 92% reduction gain, while boosting the cell-edge capacity by ~ 189% and with a greatly reduced coordination overhead space, limited to B-bit.