The capacity region for the discrete memoryless multipleaccess channel without time synchronization at the transmitters and receivers is shown to be the same as the known capacity region for the ordinary multiple-access channel. The proof utilizes time sharing of two optimal codes for the ordinary multiple-access channel and uses maximum likeliiood decoding over shifts of the hypothesized trans...

The Poisson multiple access channel (MAC) models many-to-one optical communication through an optical fiber or in free space. For this model we compute the capacity region for the two-user case as a function of the allowed peak power. Focusing on the maximum throughput we generalize our results to the case where the users are subjected to an additional average power constraint and to the many u...

Multiple access channel with feedback is an extension of classical MAC, by providing senders with ability to observe the channel output. The capacity region in the general case is not known. This report presents the main results of [1] by Cover and Leung, which is a region of achievable rates exceeding the capacity region of classical MAC (section 3). Since the coding technique used in [1] reli...

Introduction In recent years, the need for high signal-to-noise ratio and fast imaging acquisitions has driven the development of MRI systems with more receive channels. However, such multichannel systems are not always available in current clinical and research MR scanners. Array compression techniques [1-5] with the use of hybrids, Butler matrix or mode-mixing hardware allow the optimal use o...

In future high-speed self-routing photonic networks based on all-optical time division multiplexing (OTDM) it is highly desirable to carry out packet switching, clock recovery and demultplexing in the optical domain in order to avoid the bottleneck due to the optoelectronics conversion. In this paper we propose a self-routing OTDM node structure composed of an all-optical router and demultiplex...

In multiple-input multiple-output (MIMO) systems, channel estimation is of crucial importance to guarantee reliable recovery ultra-high-speed MIMO signals. This paper proposes a novel algorithm for the emerging MIMO-based orthogonal chirp-division multiplexing (OCDM) systems by utilizing unique features OCDM proposed algorithm, set pilot signals designed based on Fresnel basis, which essentiall...

Localization of sources in patients with focal seizure has recently attracted many attentions. In the severe cases of focal seizure, there is a possibility of doing neurosurgery operation to remove the defected tissue. The prosperity of this heavy operation completely depends on the accuracy of source localization. To increase this accuracy, this paper presents a new weighted beamforming method...