JPS63129727A - Mobile body communication system - Google Patents

Abstract

PURPOSE:To realize a high quality digital line by providing the diversity effect even to a line from a mobile station to a base station. CONSTITUTION:A radio F2 sent from a mobile station to a base station is converted into a wave F3 by a hybrid 6, a local oscillator 14, a mixer 15 and a band pass filter 16 and sent to a leakage coaxial cable in a direction opposite to a direction sending the wave F2. On the other hand, the hybrid 6, a receiver 17 receiving the wave F3 and a base station reception synthesizer 18 are added in addition to the receiver receiving a wave F2 in the base station and diversity reception is applied also as to the line from the mobile station to the base station. Thus, even if an obstacle 13 exists between the mobile station antenna 11 and the leakage coaxial cable 1 and the F2 radio wave is shielded, the information is received by the F3 radio wave to attain the communication with high quality without incurring the increase in the bit error rate in the digital communication.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a one-way system that is suitable for mobile digital communication [Prior Art] system"(
This is a system diagram of the LCX mobile station device described on page 119 of Yasuo Watari (written by Yasuo Watari), where (11 is LCX, (21 is
is a repeater that compensates for the loss of LCXIII, (3) is a base station transmitter, (41 is a base station receiver, (5) is a base station demultiplexer, 161 is a hybrid for distribution and combination, (7) is a mobile station transmitter, 18+ is a mobile station splitter, (9) is a mobile station receiver, (1 (l is a mobile station reception combiner, (Iυ is a mobile station antenna, a2 is a high frequency switch, and Q31 is an obstacle. , ■ is a moving object.

Next, I will explain the busyness of the operation. The radio waves F1 in the direction of movement from the base transmitted by the base station transmitter (3) are sent to the base station branching filter (5), hybrid +61. LC! It becomes a leaked radio wave through Yllll and reaches the antennas installed on both sides of the moving body (to).

Furthermore, the radio wave F1 passes through the mobile station demultiplexer +81, and is duplicated at the mobile station receiver (separately, RDI (received data) and RT
t (reception clock), and finally, the reception synthesizer 4 extracts only RD and RT, which have stronger reception electric fields.

Next, the radio wave F2 sent from the mobile station transmission WA (71) in the direction of the base is determined by the high frequency switch a, and the antenna system in the sending direction is determined by the high frequency switch a. The high frequency switch a2 automatically selects the one with the stronger electric field.) Mobile station duplexer (8), antenna αB, L
CXtll, hybrid (6), base station duplexer (5)
After that, it enters the base station receiver +41 and is demodulated and sent to RD2.
and RT2.

Digital communication is performed between the base station and the mobile object in the manner described above.

[Problem that the invention seeks to solve]

Conventional mobile digital communication equipment was configured as described above, so for radio waves from the base station to the mobile station,
Space diversity reception can be performed using multiple antennas of the mobile station, but diversity reception cannot be performed for the radio waves from the mobile station to the base station, and there may be obstacles such as C13 between the LCXll and the mobile station antenna ←υ. When this exists, the electric field level drops, causing problems such as worsening the BER (bit error rate) of digital communications.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a mobile communication system that can perform diversity reception even for radio waves directed from a mobile station to a base station.

[Means for solving problems]

The mobile communication system according to the present invention frequency-converts radio waves sent from a mobile station to a base station, transmits the radio waves before and after the frequency conversion separately via two LGXs, and at the base station, space and frequency It is designed to perform diversity reception.

[Effect]

The diversity reception in this invention improves GGA in digital communication, that is, realizes a high quality digital line.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, I is a local oscillator, I is a mixer, and (le
is a bandpass filter, (l?) is the base station receiver for the new frequency (F3), and a& is the base station receive combiner.

Next, the operation will be explained. The diversion method from the base station to the mobile station is the same as in the prior art.

Conventionally, the direction from the mobile station to the base station was switched using a high frequency switch, and the radio wave F2 was sent out only in one direction. However, in the present invention, F2 is transmitted using a hybrid (61, local oscillator housing, mixer (14)). , and a band-pass filter αe to convert it into F3, and send it out to one side (the opposite direction to the direction in which F2 was sent out).

On the other hand, at the base station, in addition to the conventional receiver (4) that receives F2, there is also a receiver m (4) that receives hybrid f61 and F3.
Iη and a base station reception combiner Cl8), and diversity reception is performed on the link from the mobile station to the base station as well as the link from the base station to the mobile station.

In this way, by adding the diversity reception function to the line from the mobile station to the base station, even if there is an obstacle C13 between the mobile station antenna Uυ and LCXIII and the F2 radio waves are blocked, the F3 radio waves will be transmitted. This allows high-quality communication to be performed without increasing the BER in digital communication.

In the above embodiment, a one-way system from the mobile station to the base station of the communication line using LCX was explained.
Even if this is applied to a general space wave type communication line, the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, in the communication line using LCX, the line from the mobile station to the base station also has a diversity effect, so that in bidirectional communication between the base station and the mobile station, the HER This has the effect of configuring a good digital communication line.

[Brief Description of the Drawings] Fig. 1 is a system diagram of a one-way LCXCX bidirectional communication system according to an embodiment of the present invention, and Fig. 2 is a system diagram of a conventional LC
FIG. 2 is a system diagram showing X-scheme two-way communication. (11 is LCX, (21 is repeater, 13+ is base station transmitter, (4) is base station receiver, (5) is base station demultiplexer, (
61 is a hybrid, (7) is a mobile station transmitter, (8) is a mobile station demultiplexer, (9J is a mobile station receiver, concave is a mobile station reception combiner, αυ is a mobile station antenna, (13 is an obstacle) , (14
) is a local oscillator, 9 is a mixer, (lE9 is a bandpass filter, η is a base station receiver, and u8 is a base station receiver combiner. In addition, the same reference numerals in the figures indicate the same or equivalent parts. show.

Claims (1)

[Claims] In a mobile communication system in which two LCXs (leaky coaxial cables) are laid along the travel path of a mobile body and communication is carried out between the mobile body and a base station via the LCX, the mobile body communicates with the base station. A mobile communication system characterized in that a transmission signal to a base station is frequency-converted, the transmission signals before and after the frequency conversion are transmitted separately through the two LCXs, and diversity reception is performed at the base station.