In this paper, we investigate iterative interference alignment (IA) approaches for multi-input multi-output (MIMO) multicell communication systems. We proposed an iterative reweighted least square (IRLS) approach for MIMO interference channel in single-cell scenario. The basic contribution of this paper is to extend the proposed IRLS algorithm to the more practical case of aligning co-channel interference signals in orthogonal frequency division multiple access (OFDMA) based cellular systems. The simulation results show that the proposed approach achieves a superior total system sum-rate than both the conventional Orthogonal-Minimum Leakage (OR-ML) and the Orthogonal-Maximum Signal to Interference Noise Ratio (OR-MSINR) approaches.

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This letter proposes a hybrid scheme for instantaneous recovery 1+1 protection route design for all possible source-destination pairs in a network. In the proposed scheme two different coding aware scenarios, namely the TS (traffic splitting) scenario and the 2SD (two sources and a common destination) scenario, are used intelligently according to the largest effective gain first policy. We compare the total costs of all the working and protection paths obtained by the proposed scheme, the TS scenario, and the 2SD scenario. Numerical results observe that the proposed scheme achieves more resource saving than the TS or 2SD scenario in our examined networks.

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Skip Graph is a promising candidate algorithm for large scale distributed systems. The principal feature is range query functionality, but Skip Graph does not have a definite method of multicasting inside ranges designated by query issuers. Even though several simple ways can be considered, they are inefficient regarding the latency or traffic volume. In this letter, we first introduce Multi-Range Forwarding (MRF) used in Multi-key Skip Graph. MRF can be used even in normal Skip Graph, and is efficient compared to the simple ways. Second, we propose a method named Split-Forward Broadcasting (SFB). We analytically evaluate SFB and explain that SFB can roughly halve the average number of hops of MRF.

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In K-best sphere decoding algorithm (KB), the number of survivor paths K, can be integer values in all tree levels. A certain complexity is provided for each value of K. In this letter, a variant of the K-best sphere decoding algorithm for uncoded MIMO channels is proposed, namely, flexible fractional K-best algorithm (FFKB). The FFKB provides a degree of freedom in complexity in-between the discreet complexities of the traditional KB. Through the offline calculations, the FFKB determines the best operation mode for KB relative to the hardware capability from the complexity point of view.

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We propose a deterministic blocker tag (BT) detection in UHF RFID-based inventory management system. A reader lets tags respond in the specified slots and compares the expected and observed status of each slot. The response slot is determined by using a random number, a frame length, and tag’s ID. Our scheme immediately detects a BT if the expected status is different from the observed status. We show the efficiency of our scheme by computer simulation.

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