Semi-blind transmit antenna array device using feedback information and method thereof in a mobile communication system

Abstract

There is provided a transmit antenna array device with at least two antennas and a method thereof in which a transmission beam is appropriately formed based on a weight vector to be transmitted to a specific mobile station in a mobile communication system. For this purpose, a base station device has a reverse processor for processing a reverse signal received through the antenna array, a forward fading information extraction unit for extracting forward fading information from the received reverse signal, a beam formation controller for generating a weight vector for formation of a transmission beam using the forward fading information and the received reverse signal, and a forward processor having a transmission beam generator for generating a transmission beam for a transmission message based on the weight vector. A mobile station device has a forward processor for processing a received forward signal, a forward fading estimator for estimating forward fading information of the forward signal for each path, a forwarding fading encoder for combining the estimated forward fading information and encoding the combined forward fading information, and a reverse processor for multiplexing the encoded forward fading information with a transmission message and feeding back the forward fading information in the multiplexed signal to a base station.

Description

PRIORITY [0001] This application is a Divisional of U.S. application Ser. No. 09 / 802,165, filed on Mar. 8, 2001, which claims priority to an application entitled “Semi-Blind Transmit Antenna Array Device Using Feedback Information and Method Thereof in Mobile Communication System” filed in the Korean Industrial Property Office on Mar. 8, 2000 and assigned Serial No. 2000-11617, the contents of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to an antenna array device and a method thereof in a mobile communication system, and in particular, to a device and method for forming a transmission beam. [0004] 2. Description of the Related Art [0005] As the number of mobile subscribers drastically increases, the capacity of the mobile communication systems approaches a saturation point. This means that mobile communication systems are in need of more advanced applications to increase the sy...

AI Technical Summary

Benefits of technology

The present invention provides a device and method for forming a transmission beam in a mobile communication system by calculating an optimal weight vector based on forward fading information feedback from a mobile station in a base station using a forward antenna array. The device can estimate forward fading information from a signal received on a forward channel and transmit the information to a base station on a reverse channel in a mobile station of a mobile communication system using an antenna array. The device is suitable for a mobile communication system where a feedback delay time is short and a mobile station roams at a movement speed that is not greatly changed. The device can selectively use a mixed forward beam formation scheme based on the movement speed of a mobile station and the feedback delay time. The invention allows for efficient beam formation and improves communication quality in a mobile communication system.

Problems solved by technology

In this situation, when a transmission is performed toward a desired specific mobile station through a dedicated channel, as opposed to a situation where transmission to all mobile stations is performed using a base station transmission antenna through a common channel, much of the radiation energy except radiation energy for the specified mobile station is useless and the unnecessary radiation energy becomes interference signals to other mobile stations.

The reason for assuming that a single antenna is used in the mobile station is that the mobile station does not typically use an antenna array due to limitations of cost, size, and mobility.

Despite the advantage of simple structure, the Raleigh transmission antenna array using a single path is not feasible for a multi-path system.

The issue is how to determine weights (different from weight vectors).

Thus, it is no use analyzing a received reverse signal to obtain the instant fading coefficient of the forward channel.

However, the blind beam formation has a slightly lower performance than the non-blind beam formation using an optimal weight vector calculated by Eq.

While the Thompson antenna array structure can be used as a transmission antenna array system in a multi-path environment, the use of an average fading power makes it impossible to calculate a precise weight vector.

The limitation of the Thompson antenna array in calculating a precise weight vector decreases the performance of the antenna array system.

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