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    High-speed self-configuring networks based on cost-effective plug-and-play optical (PPO) nodes
    (The University of Texas at Dallas, 2013-06-18) Fumagalli, Andrae; Hui, Rongqing; Maloberti, F. (Franco); Gregori, Stefano; Cerutti, Isabella, 1973-; Tacca, Marco, 1973-; Eric Jonsson School of Engineering and Computer Science.
    This proposal visualizes a future ad-hoc multi-gigabit network infrastructure connecting a very large number of inexpensive optical nodes. Such nodes will look like today’s Fast Ethernet switches, providing however, 2-3 orders of magnitude higher bandwidth, and larger geographical network coverage. Users will connect nodes using already installed fibers by a simple plug-and-play operation. Once connected, the Plug-and-Play Optical (PPO) nodes will continuously communicate with other nodes for a self-configuration of both network and nodes. An on-board optical micro-lab, advanced transmission models and an intensive signal processing are the key components to build a system that is able to intelligently adjust optical data flows and wavelength selection. The PPO node configuration will account for varying traffic patterns and changing conditions of the optical physical layer, e.g., introduction and removal of PPO nodes, aging of optical components, temperature changes, soft failure of network elements. The objective of this proposal is to identify the required technologies, to study protocols and algorithms, to develop suitable transmission models, to design and fabricate critical parts of an integrated optical micro-lab that will make the envisioned scenario a reality, and to amalgamate all the achieved results for proving the PPO node concept feasibility.
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    Combining cooperative link layer protocols with distributed routing protocols in mobile ad hoc networks – perspectives and performance analysis
    (The University of Texas at Dallas, 2013-06-18) Vijayasankar, Kumaran, 1984-; Kannan, Lakshmi Narasimhan, 1984-; Ilango, Sathya; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.
    In cooperative link layer protocols the use of relay nodes may increase the capacity of the radio links. The study in this paper investigates what (if any) performance gain may be passed onto the routing protocol of a mobile ad hoc network. Two popular routing protocols are considered, AODV and OLSR, as each provides a unique route acquisition mechanism. A distributed procedure to choose the relay node at the link layer is combined with the two routing protocols. Analysis via simulation confirms some expected (and perhaps some other less expected) benefits when using a cooperative link layer protocol in place of a non-cooperative one, e.g., improved delivery ratio, end-to-end delay, and reduced signaling overhead.
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    Optimized transmission power levels in a cooperative ARQ protocol for microwave recharged wireless sensors
    (The University of Texas at Dallas, 2013-06-18) Monti, Paolo, 1973; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.
    The Generic Autonomous Platform for Sensor Systems, or GAP4S, is a maintenance-free wireless sensor network in which the sensor node battery does not need to be replaced. Power is delivered to the sensor node via a microwave signal that is radiated by a base-station. The base-station also acts as the entry point to a wider communication network, e.g., the Internet. This paper describes an automatic repeat request (ARQ) protocol that may be used in GAP4S to yield reliable and fair data transmission from the sensor nodes to the base-station. The protocol takes advantage of cooperative communication, whereby neighboring sensor nodes help during the retransmission process. The transmission power level is optimized at each sensor node to increase the saturation throughput of the ARQ protocol.
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    A link state advertisement (LSA) protocol for optical transparency islands
    (The University of Texas at Dallas, 2013-06-18) Das, Shovan, 1979-; Tabrizi, Reza Roshani, 1976-; Monti, Paolo, 1973-; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.
    Plug and play optical (PPO) nodes can be used to ease the deployment of optical networks. Once plugged, PPO nodes provide all-optical circuits between client nodes to alleviate the electronic processing bottleneck of high speed networks. PPO nodes must self-adjust to changes of the optical physical topology and fiber propagation characteristics, and provide wavelength routing functionalities to client nodes. This paper presents a protocol, the TI-LSA protocol, for physical topology discovery at the PPO node layer, e.g., it may be used to advertise available optical resources and changing conditions of the optical physical layer. The protocol is based on the link state advertisement (LSA) principle and modified to take advantage of the transparency island (TI) properties in the optical data plane. As discussed in the paper, the proposed TI-LSA protocol is a scalable solution to the problem of topology discovery and update in PPO networks when the optical transparency island size is relatively small.
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    A queueing model for PCEP (Path Computation Element Protocol)
    (The University of Texas at Dallas, 2013-06-18) Yu, Juanjuan, 1978-; He, Yue; Wu, Kai; Tacca, Marco, 1973-; Fumagalli, Andrea; Vasseur, Jean-Phillippe; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.
    Path computation elements (PCE’s) are used to compute end-to-end paths across multiple areas. Multiple PCE’s may be dedicated to each area to provide sufficient path computation capacity and redundancy. An open problem is which PCE should be chosen to send the path computation request to, that may be a non trivial problem if PCE’s have uneven processing capacities. This paper presents a product form queueing model to estimate the latencies in path computation while accounting for the arrival rate of path computation requests. The model is used to find the PCE selection policy to minimize the average expected latencies in path computation. The model is validated against two simulation benchmarks obtained using OPNET, i.e., a network of queues and the multi protocol label switching with traffic engineering (MPLSTE) network running the PCE communication protocol (PCEP). The study shows that the use of product form yields approximations that are up to 15% at practical offered loads. Moreover, the PCE selection policy derived under the product form assumption is showed to be effective in minimizing the overall expected latencies in path computation.
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    MAGIC: Mobile Auxiliary Gateways Improve Connectivity of wireless sensor networks
    (The University of Texas at Dallas, 2013-06-18) Fumagalli, Andrea; Maloberti, F. (Franco); Nosratinia, A.; Panahi, I. M.; Saquib, M.; Tacca, Marco, 1973-; Eric Jonsson School of Engineering and Computer Science.
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    A cross layer routing metric with wireless cooperative protocols
    (The University of Texas at Dallas, 2013-06-18) Vijayasankar, Kumaran, 1984-; Kannan, Lakshmi Narasimhan, 1984-; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.
    Cooperative link layer protocols are typically used in single hop networks. In such protocols, a special node called the relay node helps deliver frames from a source to a destination. The performance benefits of cooperation at link layer can be streamlined into multi-hop networks as well. In multi-hop networks, a frame is sent from an original source to the final destination through a series of intermediate nodes. The paper extends the expected transmission time metric — proposed for multi-hop wireless ad hoc networks — to the context of cooperative IEEE 802.11 link layer protocol. The designed metric is called cooperative expected transmission time (CETT). CETT carefully accounts for the higher probability of successful frame transmission and therefore the reduction in expected transmission time brought about by the relay node in the cooperative protocol. CETT jointly optimizes both the route computation and the selection of the cooperative relay at the link layer. Route optimization helps jointly choose the best set of intermediate nodes and cooperation optimization helps choose the best relay node for each link in the multi-hop. As a result, CETT helps distinguish the case wherein it is better to use a node as a relay as compared to using it as an intermediate node. For comparison, the case where cooperation is applied after route computation is also presented. Minimizing the expected transmission time may result in more efficient link utilization and increased overall end-to-end network throughput. It is also shown that joint optimization of route and relay selection is better than finding routes and then applying cooperation.
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    Stochastic preplanned restoration algorithms
    (The University of Texas at Dallas, 2013-06-18) Fumagalli, Andrea; Valcarenghi, Luca, 1972-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.
    The ability of overcoming service interruptions, i.e., resilience, has always been an irremissible requirement for communication networks. Resilient schemes can either reserve in advance network spare resources (protection schemes) or found them upon failure occurrence (restoration schemes). While fixed protection schemes have been extensively used thus far in the telephone industry, the envisioned dynamic Optical Layer (OL) and the lack of flexibility proper of protection schemes are driving network designer to resort to restoration schemes. By dynamically looking for backup paths of spare wavelengths upon failure occurrence, restoration schemes have the potential to yield efficient and flexible resource reservation. However restoration schemes, generally, present long failure recovery time (i.e., the time required to restore the disrupted connections). This is mainly due to the heavy signaling that originates upon failure occurrence. In high capacity WDM networks, the presence of many connections concurrently seeking restoration exacerbates the above problem as, in existing restoration schemes, coordination among restoration attempts may further slow down the process completion. To exploit the flexibility of restoration schemes and decrease their failure recovery time and resource contention, the authors propose a class of fast and efficient path restoration schemes called Stochastic Preplanned Restoration (SPR) schemes. In the SPR schemes each active connection is associated with an agent resident at the connection master node. Communication between agents is not allowed. This permits to reduce the coordination required during the failure recovery process. Distinct restoration paths are precomputed at the connection master node at the time the connection is set up. Upon failure of the connection working path, one of the preplanned paths is randomly selected as restoration path depending on specific probabilities calculated by the connection agent. The proposed schemes require limited signaling upon failure occurrence as coordination among the agents involved in the restoration process is not required. Therefore, the schemes are fast and scalable in terms of number of network nodes, link or fiber capacity, and number of connections. Yet, presented results show that the SPR schemes may considerably decrease the blocking probability of the restoration attempts when compared to other distributed restoration schemes, such as alternate routing, and perform closely to centralized schemes based on ILP solutions.
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    Chromatic dispersion and self-phase modulation in multi-hop multi-rate WDM rings
    (The University of Texas at Dallas, 2013-06-18) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Potasek, Mary J.; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.; New York University. Courant Institute.
    When compared to first generation and single-hop optical networks, multi-hop and multi­rate (M & M) network architectures have the advantage of significantly reducing network design cost under a variety of wavelength-to-terminal cost ratios. This report investigates how fiber chromatic dispersion and self-phase modulation may affect such cost reduction in M & M WDM rings.
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    Voice over IP data collection in inter-vehicular environment: Analysis results
    (The University of Texas at Dallas, 2013-06-18) Petracca, Matteo; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.; Eric Jonsson School of Engineering and Computer Science. Center for Robust Speech Systems.; Politecnico di Torino. Internet Media Group.
    This report contains the analysis results of the experimental VoIP traces collected in November and December 2006 at The University of Texas at Dallas. Starting from the collected traces, two main analyses have been performed. The behavior of VoIP transmissions in an intervehicular scenario has been studied as a function of the bit rate, and as a function of the Data Retry Limit value provided by the CSMA/CA protocol implemented in the IEEE802.11 standards.
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    Cooperative ARQ protocols in slotted radio networks
    (The University of Texas at Dallas, 2013-06-18) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Gupta, Puja, 1980-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.
    In conventional (non-cooperative) automatic repeat request (ARQ) protocols for radio networks, the corrupted data frames that cannot be correctly decoded at the destination are retransmitted by the source. In cooperative ARQ protocols, data frame retransmissions may be performed by a neighboring node (the relay) that has successfully overheard the source’s frame transmission. One advantage of the latter group of ARQ protocols is the spatial diversity provided by the relay. The first delay model for cooperative ARQ protocols is presented in this paper. The model is analytically derived for a simple set of retransmission rules that make use of both uncoded and coded cooperative communications in slotted radio network. The model estimates the delay experienced by Poisson arriving frames, whose retransmissions (when required) are performed also by a single relay. Saturation throughput, frame latency and buffer occupancy at the source, and relay are quantified and compared against two non-cooperative ARQ protocols.
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    Shared protection ILP formulation
    (The University of Texas at Dallas, 2013-06-18) Huang, Wanjun, 1978-; Razo, Miguel; Billenahalli, Shreejith; Sivasankaran, Arularasi; Tang, Limin, 1977-; Vardhan, Hars; Monti, Paolo, 1973-; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.; Royal Institute of Technology. NeGONet Group.
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    Single-source single-relay cooperative ARQ protocols in TDM radio networks
    (The University of Texas at Dallas, 2013-06-18) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Gupta, Puja, 1980-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.; Scuola Superiore Sant’Anna. Center of Excellence for Communication Networks Engineering (CEIRC).
    In conventional (non-cooperative) automatic repeat request (ARQ) protocols for radio networks, the corrupted data frames that cannot be correctly decoded at the destination are retransmitted by the source. In cooperative ARQ protocols, data frame retransmissions may be performed by a neighboring node (the relay) that has successfully overheard the source’s frame transmission. One advantage of the latter group of ARQ protocols is the spatial diversity provided by the relay. The first delay model for cooperative ARQ protocols is derived in this paper. The model is analytically derived for a simple set of retransmission rules that make use of both uncoded and coded cooperative communications in slotted radio networks. The model estimates the delay experienced by Poisson arriving frames, whose retransmissions (when required) are performed also by a single relay. Saturation throughput, data frame latency, and buffer occupancy at both the source and relay are quantified and compared against two non-cooperative ARQ protocols.
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    UTD mote system (UTMOST): improving functionalities in wireless sensor nodes
    (The University of Texas at Dallas, 2013-06-18) Litovsky, Gustavo; Tacca, Marco, 1973-; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science.
    The UTD mote system (UTMOST) is a low power all purpose platform for wireless sensor nodes (WSN) based on off-the-shelf components. UTMOST offers a number of improved functionalities over previously designed platforms, e.g., energy consumption, wireless reprogramming, processing frequency, and storage capability. This paper details how hardware components are selected and integrated to enable such improvements. Experimental measurements demonstrate, among other things, a reduction of 37% in sleep current compared to previous platforms. The proposed design enables extended remote programming and lower maintenance, longer lifetime, and the support of more computational intensive applications.
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    A scalable wavelength assignment algorithm using minimal number of wavelength converters in resilient WDM networks
    (The University of Texas at Dallas, 2013-06-18) Razo, Miguel; Billenahalli, Shreejith; Huang, Wanjun, 1978-; Sivasankaran, Arularasi; Tang, Limin, 1977-; Vardhan, Hars; Tacca, Marco, 1973-; Fumagalli, Andrea; Monti, Paolo, 1973-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.; Royal Institute of Technology. NeGONet Group.
    Careful wavelength assignment (WA) to support lambda services is necessary to reduce the total number of wavelength converters (WCs), which are required every time the wavelength continuity constraint cannot be met in wavelength division multiplexing (WDM) networks. With the successful introduction of reconfigurable optical add-drop multiplexers (ROADMs) and related technologies, WDM networks are now growing in size, both in the number of optical nodes and number of wavelengths supported, thus requiring WA algorithms that scale with the network size. This paper presents a scalable and efficient WA algorithm that aims to reduce the total number of WCs in WDM networks bearing static lambda services. The WA algorithm is applicable to both unprotected and (dedicated) protected lambda services. In the latter case, wavelength continuity constraint between the working and the protection path is taken into account. The WA algorithm is then used to quantify the tradeoff between using tunable optical transceivers versus number of WCs to cope with the wavelength continuity constraint.
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    Plug-and-play optical node architectures and their built-in optical fiber characterization techniques
    (The University of Texas at Dallas, 2013-06-18) Hui, Rongqing; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science.; University of Kansas. Department of Electrical Engineering and Computer Science.
    Cost-effective plug-and-play optical (PPO) nodes may enable a new generation of self-configuring and simple-to-deploy optical networks. Three possible PPO node architectures are discussed in the paper along with their built-in opitcal fiber characterization techniques.
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    Achieving reliable networking for the generic autonomous platform for sensor systems (GAP4S)
    (The University of Texas at Dallas, 2013-06-18) Monti, Paolo, 1973-; Eric Jonsson School of Engineering and Computer Science.
    Networks of wireless integrated sensors are often used to monitor parameters distributed in the environment. These parameters are related to a variety of applications such as security, patient monitoring, chemical and biological hazard detection. Some solutions rely on replaceable batteries with a limited life-time to provide long-term sensor operation. Others envision short transmission range sensors (few meters) that harvest their energy from various environmental sources (e.g., solar, vibrations, acoustic noise). The Generic Autonomous Platform for Sensors (GAP4S) project explores an approach for wireless sensors that is complementary to these and other pre-existing solutions. In GAP4S, the wireless sensor micro-battery is remotely recharged via a microwave signal. Medium transmission ranges in the tens to hundreds of meters are possible. Within these wireless transmission ranges, a base-station collects data transmitted by the sensors and acts as the access point to a wider (typically wired) communication network, e.g., the Internet. The authorized user can, therefore, remotely connect to, monitor, and manage both the sensor network and the individual sensors. An essential component of GAP4S is its end-to-end network reliability solution, which ensures the delivery of data generated at the sensor to the interested user across both the wireless and wired segments. This dissertation investigates ways to achieve reliable networking for GAP4S over both the wireless and the wired segments. A specially designed solution is provided in each segment. In the wireless segment, error-free transmissions from the sensor node to the base-station is achieved using automatic repeat request (ARQ) protocols at layer 2. Two classes of ARQ protocols are designed and compared. The first is the conventional ARQ, whereby the data frame is retransmitted by the originating sensor until successfully received by the base-station. The second class takes advantage of cooperative radio communications, whereby multiple neighboring sensor nodes may combine their efforts during the retransmission process. The ARQ protocols are compared in terms of their saturation throughput, i.e., the maximum data flow that the sensor node can sustain constrained to the available energy amount. In a variety of scenarios--current and future expected circuit energy consumptions--the cooperative ARQ protocols may more than double the saturation throughput when compared to conventional ARQ protocols. Equivalently, it can be said that the energy required to operate the system may be reduced by half. In the wired segment, fault tolerant networking is achieved by means of protection switching at layer 3. Given the increasingly widespread use of Wavelength Division Multiplexed (WDM) backbone networks, the protection switching scheme is designed to operate in conjunction with WDM. Optical circuits are made reliable by means of a Shared Path Protection (SPP) switching scheme. The SPP scheme is generalized to guarantee Differentiated levels of Reliability (DiR) to the user. In the SPP-DiR combined scheme the desired level of reliability may be guaranteed while minimizing the required network resources, i.e., wavelengths. This feature makes it possible to support more optical connections and users when compared to other existing protection switching schemes.
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    Digital subcarrier cross-connects (DSXCs)
    (The University of Texas at Dallas, 2013-06-18) Hui, Rongqing; Huang, Wanjun, 1978; Razo, Miguel; Tacca, Marco, 1973; Fumagalli, Andrea; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.
    Traditional (analog) Frequency Division Multiplexing (FDM) was widely used in the pre-SONET/SDH era, to multiplex transport channels together using spectral diversity. These transport solutions were then gradually abandoned due in part to their low spectral efficiency and with the advent of Time Division Multiplexing (TDM), which lead to synchronous transmission techniques, such as SONET and SDH. Another problem of traditional FDM or Subcarrier Multiplexing (SCM) ─ being analog ─ is its susceptibility to accumulated waveform distortion and crosstalk. For these reasons FDM is not competitive in today’s transport networks. Digital signal processing continues to reach new record high rates, thus enabling Digital Subcarrier Crossconnects (DSXCs) to operate even at the high transmission rates of optical signals. In DSXC, the incoming subcarriers are switched to the outgoing subcarriers by a controlled Radio Frequency (RF) crossbar switch. The power consumption required to switch subcarriers in and out is estimated to be only a fraction of the power dissipated by current TDM and packet switching based transport network solutions. Multiple DSXCs can be combined to design Digital Subcarrier Optical Networks (DSONs) [1], which are a promising energy efficient alternative to current electronic-based transport network techniques, e.g., OTN/SONET/SDH/MPLS-TP. The DSXC’s basic functionalities and modules are introduced and discussed in this paper.
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    An automatic repeat request protocol for cooperative slotted radio networks
    (The University of Texas at Dallas, 2013-06-18) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Gupta, Puja, 1980-; Eric Jonsson School of Engineering and Computer Science. Open Networking Advanced Research (OpNeAR) Laboratory.
    In conventional (non-cooperative) radio networks, the data frames, that are corrupted by errors during the transmission in a fading environment, are retransmitted by the source. In cooperative radio networks, frame retransmission may be performed by a neighboring node that has successfully overheard the source’s frame transmission. The advantage of the latter is the spatial diversity that is provided by the cooperative node. In addition, the retransmitted frame may have incremental redundancy for improved performance. In this paper a simple automatic repeat request (ARQ) protocol is specified that takes advantage of coded cooperative communication in slotted, single-hop radio networks. An exact analytical formulation is presented to compute the delay experienced by Poisson arriving frames whose retransmission (when needed) is performed by one cooperative node. The study reports significant quantitative advantages of the coded cooperation ARQ protocol in terms of both throughput and latency, when compared to non-cooperative ARQ protocols.
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    Single-source single-relay cooperative ARQ protocols in TDM radio networks
    (The University of Texas at Dallas, 2013-06-18) Cerutti, Isabella, 1973-; Fumagalli, Andrea; Gupta, Puja, 1980-; Eric Jonsson School of Engineering and Computer Science.
    In conventional (non-cooperative) automatic repeat request (ARQ) protocols for radio networks, the corrupted data frames that cannot be correctly decoded at the destination are retransmitted by the source. In cooperative ARQ protocols, data frame retransmissions may be performed by a neighboring node (the relay) that has successfully overheard the source’s frame transmission. One advantage of the latter group of ARQ protocols is the spatial diversity provided by the relay. The first delay model for cooperative ARQ protocols is derived in this paper. The model is analytically derived for a simple set of retransmission rules that make use of both uncoded and coded cooperative communications in slotted radio networks. The model estimates the delay experienced by Poisson arriving frames, whose retransmissions (when required) are performed also by a single relay. Saturation throughput, data frame latency, and buffer occupancy at both the source and relay are quantified and compared against two non-cooperative ARQ protocols.