This letter investigates the training convergence in range-based cooperative positioning with stochastic positional knowledge. Firstly, a closed-form of squared position-error bound (SPEB) is derived with error-free ranging. Using the derived closed-form, it is proved that the SPEB reaches its minimum when at least 2 out of N (> 2) agents send training sequences. Finally, numerical results are provided to elaborate the theoretical analysis with zero-mean Gaussian ranging errors.

Multicast delivery in heterogeneous wireless networks requires careful coordination, in order to take full advantage of the resources such an interworking network environment can offer. Effective coordination, however, may require interworking signaling from coordinating network entities to receivers of a multicast service. Scalable delivery of such signaling is of great importance, since a large number of receivers may be interested in a multicast service. This paper therefore investigates the use of a multicast signaling channel (MSCH) to carry such interworking signaling in a scalable manner. Applications of interworking signaling for multicast service delivery in heterogeneous wireless networks are presented, motivating the need for an MSCH. Then a comparative study is performed analysing potential benefits of employing an MSCH for signaling message delivery compared to conventional unicast signaling. The analysis reveals that the benefits of the MSCH depend mainly on the selection of an appropriate signaling network to carry the MSCH and also on efficient addressing of a subset of receivers within the MSCH. Based on the findings, guidelines for the selection of a suitable signaling network are provided. Furthermore a novel approach is proposed that allows efficient addressing of a subset of receivers within a multicast group. The approach minimizes the required signaling load on the MSCH by reducing the size of the required addressing information. This is achieved by an aggregation of receivers with common context information. To demonstrate the concept, a prototype of the MSCH has been developed and is presented in the paper.

Cognitive radio provides a feasible solution for alleviating the lack of spectrum resources by enabling secondary users to access the unused spectrum dynamically. Spectrum sensing and learning, as the fundamental function for dynamic spectrum sharing in 5G evolution and 6G wireless systems, have been research hotspots worldwide. This paper reviews classic narrowband and wideband spectrum sensing and learning algorithms. The sub-sampling framework and recovery algorithms based on compressed sensing theory and their hardware implementation are discussed under the trend of high channel bandwidth and large capacity to be deployed in 5G evolution and 6G communication systems. This paper also investigates and summarizes the recent progress in machine learning for spectrum sensing technology.

This letter presents a novel opportunistic cooperative positioning approach for orthogonal frequency-division multiple access (OFDMA) systems. The basic idea is to allow idle mobile terminals (MTs) opportunistically estimating the arrival timing of the training sequences for uplink synchronization from active MTs. The major advantage of the proposed approach over state-of-the-arts is that the positioning-related measurements among MTs are performed without the paid of training overhead. Moreover, Cramer-Rao lower bound (CRLB) is utilized to derive the positioning accuracy limit of the proposed approach, and the numerical results show that the proposed approach can improve the accuracy of non-cooperative approaches with the a-priori stochastic knowledge of clock bias among idle MTs.

This paper presents a novel approach for mobile positioning in IEEE 802.11a wireless LANs with acceptable computational complexity. The approach improves the positioning accuracy by utilizing the time and frequency domain channel information obtained from the orthogonal frequency-division multiplexing (OFDM) signals. The simulation results show that the proposed approach outperforms the multiple signal classification (MUSIC) algorithm, Ni's algorithm and achieve a positioning accuracy of 1 m with a 97% probability in an indoor scenario.

Software radio promises to bring unparalleled flexibility and reconfigurability to wireless systems, with enormous commercial potential. As the next decade progresses SDR is expected by many to emerge as the dominant design in the commercial wireless marketplace. However, significant practical issues associated with security and regulation exist which, if not adequately addressed, could threaten to result in regulatory hurdles precluding, or at least delaying, its deployment--a regulator could be understandably hesitant about authorising the operation of a handset whose radio emissions can be determined by an end user downloading and using unproven software from an arbitrary source post-purchase. In this article we describe the Reconfiguration Management Architecture--a pragmatic technological approach, developed within the framework of Mobile VCE research, that offers solutions to this and other associated SDR problems. The RMA approach fully acknowledges and builds upon the necessary interaction between the user terminal and the network to allow full validation of a reconfigured user device prior to realtime operational authorisation. Such an architecture allows responsibility for validation to be delegated and assigned by a national regulator to, for example, a mobile network operator. Such a capability can, in turn, facilitate the creation and growth of an open market in downloadable software provision, which itself promises to encourage rapid development of new capabilities, applications and innovation. New business models and revenue streams may be expected to result. This article describes the basic technical concepts associated with the RMA, explaining the key functionalities residing within the terminal and the network and their interrelationships. The RMA is presently being evaluated as part of the SDR Forum's security and architecture work. It promises to provide realistic solutions that could accelerate the successful commercial deployment and rollout of SDR technology to the benefit of the industry, across the whole value chain.