Rana Abbas

Random Access for M2M Communications With QoS Guarantees

We propose a novel random access (RA) scheme with the quality of service (QoS) guarantees for machine-to-machine (M2M) communications. We consider a slotted uncoordinated data transmission period during which machine type communication (MTC) devices transmit over the same radio channel. Based on the latency requirements, MTC devices are divided into groups of different sizes, and the transmission frame is divided into sub-frames of different lengths. In each sub-frame, each group is assigned an access probability based on which an MTC device decides to transmit replicas of its packet or remain silent. The base station employs successive interference cancellation to recover all the superposed packets. We derive the closed-form expressions for the average probability of device resolution for each group, and we use these expressions to design the access probabilities. The accuracy of the expressions is validated through Monte Carlo simulations. We show that the designed access probabilities can guarantee the QoS requirements with high reliability and high energy efficiency. Finally, we show that RA can outperform standard coordinated access schemes as well as some of the recently proposed M2M access schemes for cellular networks.

Analysis on LT codes for unequal recovery time with complete and partial feedback

In this paper, we investigate the impact of feedback in LT codes to guarantee unequal recovery time (URT) for different message segments. We analyze the URT-LT codes using the AND-OR tree for two scenarios: complete and partial feedback. We derive the necessary conditions for these two feedback schemes to achieve the required recovery time. We validate the analysis by simulation and highlight the cases where feedback is advantageous.

Design of Probabilistic Random Access in Cognitive Radio Networks

In this paper, we focus on the design of probabilistic random access (PRA) for a cognitive radio network (CRN). The cognitive base station (CBS) allows the secondary users (SUs) to reuse the sub-channels of the primary users (PUs) provided that the interference of the SUs to the PUs is below a predetermined threshold. PUs transmit over a fixed set of channels with fixed transmission powers that are scheduled by the CBS. With this prior information, CBS optimizes the probabilistic random transmissions of the SUs. In each time slot, SUs transmit over a random number of channels d, chosen uniformly at random, according to a certain degree distribution function, optimized by the CBS. Once the signals of the SUs and PUs are received, CBS then implements successive interference cancellation (SIC) to recover both the SUs’ and PUs’ signals. In the signal recovery, we assume that the PUs’ signals can be recovered if the interference power (IP) of the SUs to the PUs is below a predetermined threshold. On the other hand, we assume the SUs’ signals can be recovered if its received SINR is above a predetermined threshold. We formulate a new optimization problem to find the optimal degree distribution function that maximizes the probability of successfully recovering the signals of an SU in the SIC process under the SINR constraints of the SUs while satisfying the IP constraints of the PUs. Simulation results show that our proposed design can achieve higher success probabilities and a lower number of transmissions in comparison with conventional schemes, thus, significantly improving signal recovery performance and reducing energy consumption.

On SINR-Based Random Multiple Access Using Codes on Graph

We revisit random multiple access (RMAC) for wireless systems with successive interference cancellation (SIC) employed at the access point (AP). We consider an asymptotically large number of users that transmit over a large number of orthogonal sub-channels. In each transmission block, each user chooses a degree

Rateless Coding Scheme Based on Autoregressive-Moving-Average Model over Ka-Band Links

d

Performance analysis and optimization of LT codes with unequal recovery time and intermediate feedback

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Ultra-Reliable Low Latency Cellular Networks: Use Cases, Challenges and Approaches

d

On the performance of massive grant-free NOMA

is a random variable that follows a predefined degree distribution

Random Multiple Access for M2M Communications with QoS Guarantees.

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Short Block-length Codes for Ultra-Reliable Low-Latency Communications.

. Then, users transmit in