KR20010031496A - Radiocommunications system and control device - Google Patents

Abstract

The present invention relates to a wireless communication system and a control device, wherein in a wireless communication system consisting of a wireless cell, data channels implemented in the wireless cell can be distinguished by an assigned spreading code. The spreading code set is specifically assigned to the combined radio cell, in which case the spreading code set is distinguished from the spreading code sets used by adjacent, combined radio cells (code-reuse). The wireless communication system is particularly suitable for use in third generation TD / CDMA mobile wireless networks.

Description

RADIO COMMUNICATIONS SYSTEM AND CONTROL DEVICE}

The concept of ″ transmission ″ includes communication in the form of point-to-point communication and / or transmission and / or reception in the form of point-to-multipoint communication. Typically, for transmission, a transmitting device, a receiving device and / or a processing device are used.

In a radio communication system, information (such as voice, image information or other data) is transmitted via a transmission channel, which in the case of a wireless communication system is made possible through the air interface by using electromagnetic waves. Electromagnetic wavelengths may be transmitted at carrier frequencies in the frequency range provided for each system. In Global System for Mobil Communication (GSM), the carrier frequency is in the 900 MHz range. In future wireless communication systems such as, for example, Universal Mobile Telecommunication System or other third generation systems, frequencies in the approximately 2000 MHz frequency range are provided.

The transmitted electromagnetic waves are attenuated by losses due to reflection, refraction and radiation due to earth curvature. Thus, the reception power provided to the receiving radio station is reduced. The attenuation is dependent on location and, in the case of a moving station, on time.

There is a radio interface between the transmitting radio station and the receiving radio station, through which data transmission is performed using electromagnetic waves. In German patent 195 49 158 a radio communication system using CDMA subscriber separation (CDMA code division multiple access) is known, in which case the air interface additionally makes time multiple subscriber separation (TDMA time division multiple access). Knowing the spreading code of multiple subscribers, the JD method (Joint Detection joint detection) is used to improve the detection of transmitted data. In this case, it is known that at least two data channels can be assigned to one connection via the air interface. Each data channel can be distinguished by an individual spreading code. In addition, the data channel means a logic channel, through which desired data can be transmitted.

It is known in GSM mobile radio networks that data is transmitted as a radio block (Burst burst) and a middle amble with a known symbol is transmitted within the radio block. The middle amble may be used in the sense of a training sequence for tuning a radio station at a receiving side. The receiving station estimates the channel pulse response for the various transmission channels using the middle amble. In GSM mobile radio networks it is also known to integrate adjacent radio cells into one cluster and transmit in different frequency bands within the cluster of different radio cells.

The allocation of spreading codes for CDMA channels can be done in two different ways.

Random generation of spreading code: This has the disadvantage that the spreading code cannot be optimized in terms of its separability.

Fixed spreading code set: This has the disadvantage that CDMA channels assigned the same spreading code are difficult to separate in a certain state.

The present invention relates to a wireless communication system consisting of a radio cell, in particular a mobile radio network and a control device.

1 is a block circuit diagram of a mobile wireless network,

2 is a schematic diagram of a frame structure of an air interface,

3 is a schematic diagram of a radio block configuration;

4 is a schematic diagram of a code cluster consisting of radio cells.

It is an object of the present invention to provide a wireless communication system and a control device for improving the capacitive load of a wireless communication system.

The object is achieved by a wireless communication system having the features of claim 1 and a control device having the features of claim 8. Preferred refinements are given in the dependent claims,

Thus, the present invention is based on the idea that a radio cell in which a spreading code schedule is transmitted in the same frequency band therein forms a subset, wherein the same spreading code is used simultaneously within a radio cell locally adjacent to the subset. It doesn't work. Thus, it becomes possible that a limited number of spreading codes that can be separated well can be used efficiently.

An improvement of the invention also provides that the corresponding middle amble code schedule is executed. This allows a limited number of middle ambles to be allocated efficiently.

Embodiments of the present invention provide that at least one frequency cluster comprises one radio cell. In the wireless communication system of the method composed of radio cells, a data sequence transmitted in one radio cell and having an irrelevant data sequence in terms of time and frequency can be distinguished by an assigned spreading code, and a spreading code set is defined for each radio cell Are allocated to a single code cluster, and the spreading code sets assigned to the wireless cell simultaneously within the code cluster are different.

A further preferred embodiment provides that the air interface further comprises a TDMA configuration.

By this, the transmission resource and the code resource can be fully utilized efficiently and flexibly.

According to the present invention, in the system concept of the third generation mobile wireless network, in particular, by using the JD method (Joint Detection joint detection), where signal detection is made by knowing the spreading code of multiple subscribers, the possibility of separation and the capacity of subscriber signals An important advantage arises for the load.

The invention is subsequently presented in more detail in the preferred examples. The following figures are used to describe preferred embodiments of the present invention.

The wireless communication system shown in FIG. 1 corresponds to a GSM mobile wireless network known in its construction. The mobile wireless network consists of a plurality of mobile switching centers (MSCs), which are cross-coupled with one another side by side or form an entrance to a fixed network (PSTN). The mobile switching center (MSC) is also connected to at least one base station controller (BSC), respectively. Each base station controller BSC again allows access to at least one base station BS. The base station BS is a radio station capable of forming a radio link with a mobile radio station, i. E. Mobile station MS, via an air interface. The radio cell FZ is determined by the range of the base station. The allocation of resources such as codes and frequency bands for radio cells and data sequences to be transmitted may be controlled by a control device such as, for example, a base station controller (BSC).

In Figure 1, for example, three radio links for the transmission of the desired information ni and signaling information si appear between three mobile stations MS and one base station BS, in which case the mobile stations for an increase in data rate. Two data channels DK1 and DK2 are allocated to MS, and one data channel DK3 or DK4 is allocated to other mobile stations MS, respectively. The Operations and Management Center (OMC) implements the control and management of the mobile wireless network or part of the network here. The functionality of this structure is used by the wireless communication system according to the present invention, but can be transferred to other wireless communication systems in which the present invention can be used.

The base station BS is connected to an antenna device consisting of three separate emitting elements. Each individual emitting element emits in the sector direction of the radio cell supported by the base station BS. Alternatively, however, a larger number of separate emitting elements (based on adaptive antennas) may be used, so that spatial subscriber separation according to the SDMA scheme (space division multiple access) may also be used.

The base station (BS) provides the mobile station (MS) with organization information related to a LA location area and a radio cell (radio cell identification). The tissue information is transmitted simultaneously through all individual emitting elements of all antenna devices.

The connection of the desired information ni and signaling information si between the base station BS and the mobile station MS is via a multipath, caused by reflections in buildings, in addition to the directional propagation path. Directional transmission by a particular individual emitting element of the antenna device AE has a greater antenna gain than omnidirectional transmission. Connection quality is improved by directional transmission.

If the mobile station (MS) is in motion, the multiple paths, along with other disturbances, cause the receiving mobile station (MS) to signal over time and overlap the signal components from the various propagation paths of the subscriber signal. Further, it is assumed that subscriber signals of different base stations BS overlap the received signal rx of the frequency channel at the receiving point. The purpose of the receiving mobile station MS is to detect the data symbol d of the desired information ni and the signaling information si and the data of the organization information to be transmitted in the subscriber signal.

2 shows a frame structure of a wireless interface. According to the TDMA configuration, the distribution of time zones is provided in time slots ts, in which case eight time slots ts 1 to ts 8 are combined into one TDMA frame.

The entire frequency range present in the wireless system is divided into two subranges, where one portion is allocated for the uplink connection and the other for the downlink connection. The uplink connection forms a dual wireless connection with the downlink connection, in which case the same or different data rates can be transmitted on the uplink and the downlink. Corresponding to the FDMA component, the partial range is divided into a frequency band, for example, a bandwidth of B = 1.6 Mhz.

A sequence of time slots with the same number of time slots form a physical channel through a TDMA frame of frequency bands and optionally frequency jump function.

The digital data flow to be transmitted over this physical channel is first modulated. The generated data symbols are integrated into operands dt consisting of data sequences. Depending on the part of the CDMA component, the operand is spread by a spreading code, ie a CDMA code. That is, the signal form of a constant bandwidth is modulated by the data sequence. The generated chip sequence is combined with the middle amble and forms a radio block (Burst burst). The middle amble is at least different from the connected entity in the uplink.

The radio block is transmitted in the corresponding physical channel. In order for multiple radio blocks to be transmitted within one physical channel, data sequences of different radio blocks can be spread to different spreading codes individually within the physical channel, whereby the spreading codes can be separated at the receiver. The constant physical channel forms a CDMA channel (CC) with a constant spreading code.

A logic channel, such as a data channel DK or a control channel, is assigned to the CDMA channel CC according to the schematic diagram.

3 shows a radio block of the method for the desired data transmission in operand dt with data symbol d, into which a section with a known middle amble m is inserted. By spreading the operand dt, for example, K data channels DK1, DK2, DK3, ... DKK on the receiving side can be separated by the CDMA component part. A specific amount of energy E per symbol is allocated to each of the data channels DK1, DK2, DK3, ... DKK on the secondary side.

The spread of the individual symbols from the data with the Q chip means that the Q subsection of the duration Tc is transmitted within the symbol period Ts. In this case, the Q chips form individual CDMA codes. The middle amble m is made of L chips similar to the duration Tc. A separate amble m of L composite codes is used at least on the uplink per connection. The necessary M different middle ambles are derived from the base middle ambles of M * W length, in which case the maximum number of subscribers (connections) and the maximum number of expected channel coefficients (W) of the channel pulse response are shown. The connecting individual middle amble m is induced by rotating the base middle amble code to the right through the W * m chips and by periodically spreading to L ≧ (M + 1) * W−1 chips.

By using a common middle amble (m) for multiple data channels (DK1 and DK2) with one connection (V1, V2, V3), more data channels (DK1 and DK2) in the time slot (ts) It is possible to be transmitted.

Also within the time slot ts, a guard time guide of duration Tg is provided for compensation of different signal propagation times through successive time slot ts connections.

For example, the frequency of the mobile station MS or a control channel for time synchronization is supplied to a preset time point in the multi-frame instead of each frame.

Parameters of the air interface are as follows, for example.

Chip Rate: 4.096 Mcps

Frame duration: 10 ms

Number of time slots: 16

Duration of one time slot: 625 ㎲

Diffusion Variable: 16

Modulation Method: QPSK

Bandwidth: 5 MHz

This parameter allows for the best possible blending of the FDD (Frequency Division Duplex) -TDD (Time Division Duplex) -mode for the third mobile radio generation.

The variables can be set differently in the ascending direction MS-> BS (uplink) and in the descending direction (BS-> MS) (downlink).

As noted above, different data channels are based on different spreading codes within the physical channel. Depending on how the spreading code is used, how may spreading code be detected and how the spreading code is distributed, or where there may be no infinite number of spreading codes to which the receiving device can be well separated. It is clear how to be notified.

4 shows how a limited number of spreading codes can be efficiently allocated by a code schedule in a mobile wireless system of the cell method. For example, seven adjacent radio cells FZ, always indicated by six corners, are integrated into one so-called code cluster KC (in this case one frequency cluster FC is represented by one radio cell). Different sets of spreading codes (C1-C7) are used for each radio cell in the code cluster. In a variant embodiment the spreading code is again used for radio cells of adjacent code clusters (code reuse).

Also shown in FIG. 5 is how a limited number of spreading codes can be efficiently allocated by the code schedule in a cellular radio system. For example, seven adjacent radio cells FZ, always indicated by six corners, are integrated into one so-called code cluster KC. Within the code cluster, a different set of frequency bands F1-F7 is used for each radio cell. For example, seven adjacent frequency clusters FC are integrated into one code cluster KC. Within the code cluster, a different set of spreading codes (C1-C7) is used for each frequency cluster. In a variant embodiment the spreading code is again used for radio cells of adjacent code clusters (code reuse).

In the case of the radio communication system composed of radio cells (FZs), radio blocks transmitted in a first radio cell and having no logical relationship in terms of time and frequency are assigned different spreading codes and / or at least partially assigned different middle parts. Can be distinguished by an amble. The spreading code and / or middle amble are not used simultaneously in a second radio cell, but are transmitted to the second radio cell in the same frequency band as the first radio cell, and the second radio cell is near the first radio cell. Located in

In a variant embodiment, the spreading code used for the first radio cell is also used for the adjacent radio cell and is transmitted into the adjacent radio cell in a different frequency band than the first radio cell.

In a further variant embodiment, the spreading code used for the first radio cell is also used for non-adjacent radio cells and is transmitted into the non-adjacent radio cell in the same frequency band as the first radio cell.

In an embodiment, for the distribution of the spreading code set, the distribution of the middle amble set is made corresponding to the above scheme. The formation of code clusters related to the middle amble may of course be independent of the formation of code clusters related to spreading codes, in which case the code clusters are not necessarily associated with the same frequency cluster.

The spreading code set or the middle amble set may be detected from the base code at a radio station (MS, BS) or a control device (BSC) to which the radio station is assigned. The allocation of spreading code sets or middle amble sets for individual radio cells may be made by the central control unit (OMC) and / or the decentralized control unit (BSC). In addition, the allocation of the spreading code set or the middle amble set and the frequency resource set and the time resource set for the data channel may be made by the central control device (BSC).

In another variant embodiment, the spreading code set and the middle amble set are queried from a memory device that may be in the control device BSC.

In a further variant embodiment, the allocation of the spreading code set and the middle amble set is made dynamically by the central control unit (OMC). In addition, the spreading code set and the middle amble set are certainly preset in assembling and disassembling the mobile radio system.

In addition, the modified embodiment may be implemented only in the middle amble code schedule, not the spreading code schedule.

An additional embodiment of the present invention provides that only one frequency band is assigned to at least one radio cell.

In the use of the present invention, in the third generation mobile radio system, especially when using the JD method (Joint Detection joint detection), the detection of the signal is made from spreading code information of multiple subscribers, and the possibility of separation of subscriber signals and the workload of capacitance There is a significant advantage that arises. In the above embodiment, a joint detection receiving apparatus is provided to a radio station (MS, BS), in which case the joint detection method is implemented by a digital signal processor.

Mobile wireless networks with a combination of FDMA, TDMA, and CDMA provided in the above embodiments are suitable for the needs for third generation systems. The mobile radio network is particularly suitable for implementations consisting of GSM mobile radio networks and requiring low cost.

Claims (17)

In a wireless communication system composed of a radio cell (FZ), a) one frequency band set F is assigned to each radio cell FZ for data transmission, b) multiple radio cells (FZ) are integrated into one frequency cluster, c) frequency band sets F1-F7 assigned to the radio cell FZ within one frequency cluster are different, d) data sequences that are transmitted to one radio cell (FZ) and which have no OR in terms of time and frequency can be distinguished by a spreading code assigned thereto, e) one spreading code set (C) is assigned to each frequency cluster, f) multiple frequency clusters (FC) are integrated into one code cluster (KC), g) spreading code sets C1-C7 simultaneously assigned to frequency cluster FC within code cluster KC. The method of claim 1, a) at least partially different middle ambles (m) are assigned to a radio block transmitted in one radio cell (FZ) over an air interface and having no OR in terms of time and frequency, b) one middle amble set is allocated to each frequency cluster FC, c) multiple frequency clusters (FC) are integrated into one code cluster (KC), d) A set of middle ambles assigned to a frequency cluster FC within a code cluster KC is different. The method of claim 1, wherein At least one frequency cluster (FC) comprises only one radio cell (FZ). In a wireless communication system composed of a radio cell (FZ), a) data sequences transmitted in one radio cell (FZ) that are not OR in terms of time and frequency can be distinguished by assigned spreading codes b) spreading code set (C) is assigned to each radio cell (FZ), c) multiple radio cells (FZ) are integrated into one code cluster (KC), d) A spreading code set (C1-C7) which is simultaneously allocated to a radio cell (FZ) in a code cluster (KC) is different. The method of claim 4, wherein a) at least partially different middle ambles (m) are assigned to a radio block transmitted in one radio cell (FZ) over an air interface and having no OR in terms of time and frequency, b) one middle amble set is assigned to each radio cell (FZ), c) multiple radio cells FZ are integrated into one code cluster KC, d) A set of middle ambles simultaneously assigned to a radio cell FZ in a code cluster KC are different. The method of claim 1, wherein Wireless communication system, characterized in that the adjacent frequency cluster (FC) or radio cell (FZ) is integrated into one code cluster (KC). The method of claim 1, wherein The formation of a code cluster (KC) related to the middle amble and the formation of a code cluster (KC) related to the spreading code can be made independently of each other. The method of claim 1, wherein And wherein the wireless interface further comprises a TDMA component. The method of claim 1, wherein A radio station (MS, BS) detects received signals by a joint detection method. By assigning the frequency band and spreading code used for data transmission to the radio cell FZ by the control apparatus BSC, a) each radio cell (FZ) is assigned a set of frequency bands for data transmission, b) multiple radio cells (FZ) are integrated into one frequency cluster (FC), c) the set of frequency bands assigned to the radio cell FZ within one frequency cluster FC are different, d) data sequences transmitted to one radio cell (FZ) and which have no OR in terms of time and frequency can be distinguished by assigned spreading codes, e) one middle amble set is assigned to each frequency cluster FC, f) multiple frequency clusters (FC) are integrated into one code cluster (KC), g) A spreading code set assigned simultaneously to the frequency cluster FC within the code cluster KC is different. The method of claim 10, By assigning the frequency band, middle amble and spreading code used for data transmission to the radio cell FZ by the control apparatus BSC, a) a middle amble is assigned at least partially different to a radio block transmitted in one radio cell (FZ) over an air interface and which has no OR in terms of time and frequency, b) one middle amble set is allocated to each frequency cluster FC, c) multiple frequency clusters (FC) are integrated into one code cluster (KC), d) A control device characterized in that the set of middle ambles assigned to the frequency cluster FC within the code cluster KC is different. The method according to claim 10, wherein By assigning the middle amble and spreading code used for data transmission to the radio cell FZ by the control apparatus BSC, At least one frequency cluster (FC) comprises only one radio cell (FZ). By assigning a spreading code used for control device (BSC) data transmission to the radio cell (FZ), a) a sequence of data transmitted in one radio cell (FZ) and having no OR in terms of time and frequency can be distinguished by an assigned spreading code, b) spreading code set (C) is assigned to each radio cell (FZ), c) multiple radio cells (FZ) are integrated into one code cluster (KC), d) The control device characterized in that the spreading code set (C1-C7) simultaneously assigned to the radio cell (FZ) in the code cluster (KC) is different. The method of claim 13, By assigning the middle amble and spreading code used for data transmission to the radio cell FZ by the control apparatus BSC, a) a middle amble (m) at least partially different from a radio block transmitted over a radio interface to one radio cell (FZ) and having no OR in terms of time and frequency, b) one middle amble set is assigned to each radio cell (FZ), c) multiple radio cells FZ are integrated into one code cluster KC, d) A control device characterized in that the set of middle ambles assigned to the radio cells FZ simultaneously in the code cluster KC are different. The method according to claim 10, wherein By assigning the frequency band, middle amble and spreading code used for data transmission to the radio cell FZ by the control apparatus BSC, Control device characterized in that the adjacent frequency clusters (FC) or radio cells (FZ) are integrated into one code cluster (KC). The method according to claim 10, By assigning the frequency band, middle amble and spreading code used for data transmission to the radio cell FZ by the control apparatus BSC, The formation of the code cluster KC related to the middle amble and the formation of the code cluster KC related to the spreading code can be performed independently of each other. The method according to claim 10 to 16, By assigning the frequency band, the middle amble and the time slot ts used by the control device BSC to the data transmission to the radio cell FZ, Control device, characterized in that the wireless interface further comprises a TDMA component.