WO2006037258A1

WO2006037258A1 - A ofdm and ofdma coexistence system and a cooperation method thereof

Info

Publication number: WO2006037258A1
Application number: PCT/CN2004/001145
Authority: WO
Inventors: Ning Wang; Hexing Liu; Xiang Gao; Ying Liu; Yanwei Wu; Jiying Xiang
Original assignee: Zte Corporation
Priority date: 2004-10-09
Filing date: 2004-10-09
Publication date: 2006-04-13
Also published as: CN101015149A; CN101015149B

Abstract

A OFDM and OFDMA coexistence system and a cooperation method thereof, the coexistence system comprises : at least a OFDM or OPDMA terminal for receiving downlink information from a BS system and transmitting uplink information based on the indication of the BS; and a BS system for receiving the uplink information from the OFDM or OPDMA terminal and transmitting corresponding downlink information , the frame struq,ture of OFDM and OPDMA coexistence is realized by constituting the OFDM land OPDMA data which are in the same frequency band in TDMA fashion then the OFDM and OPDMA coexistence is realized The BS system may be a BS system with a double MAC structure or an inosculated MAC structure or a superimpose structure , and the appropriate frame structure of the OFDM and OPDMA coexistence system is realized by the BS system , then the appropriate frame structure ensures that the air interface is compatible with two different TDMA systems so that the benefit of the investor and user can be protected at the maximum extent.

Description

Coexistence system of OFDM and OFDMA and cooperative working method thereof

The invention relates to a coexistence system of two time division systems and a method for realizing different time division systems to work together, in particular to an orthogonal frequency division multiplexing (OFDM) and orthogonal frequency division multiple access (OFDM) (OFDMA, orthogonal frequency division multiplexing access) The coexistence system of these two different time division systems and their cooperative working methods. Background technique

Orthogonal Frequency Division Multiplexing (OFDM) is a common time division system with high spectrum utilization and is suitable for wireless data transmission.

The structure of the traditional OFDM system transceiver is shown in Figure 1. This uses digital modulation, such as QPSK (quadrature phase shift keying) and QAM (quadrature amplitude modulation). The encoding method can take many forms, such as RS (Reed-Solomon) code, BTC (Block Turbo Code) code, CTC (Conventional Turbo Code) code, and the like. In Fig. 1, a structure 100 of a transmitter, a structure 200 of a receiver is included. After the signal is encoded and interleaved, digitally modulated, the pilot is inserted, and the inverse fast Fourier transform (IFFT operation) is performed after serial-to-parallel conversion, and then subjected to parallel-serial conversion, and sent to the radio unit for processing and sent to the transmitting antenna. The purpose of inserting the cyclic prefix and the force window here is to overcome the multipath interference and to facilitate the fast Fourier transform (FFT operation) on the receiver side to reduce the spur of the transmitted signal. The receiving process is: after the RF-transformed signal from the receiving antenna is subjected to A/D processing, converted into digital information, serial-to-serial converted, FFT operation and parallel-to-serial conversion are performed, channel estimation and channel correction are performed, and digital is performed. Demodulation, deinterleaving and decoding, complete the processing.

The generalized OFDM system includes both OFDM and OFDMA systems. The basic principle of OFDMA is similar to OFDM. The other two regions are that the burst allocation of the OFDMA system is performed in the two-dimensional interval of time and frequency, while the OFDM system bursts. Assignments are only allocated on the time dimension. Compared with the traditional OFDM system, the OFDMA system has more flexible bandwidth allocation and is more suitable for cellular networking, and thus has attracted more and more attention.

In the IEEE802.16 standard, although the two technologies of OFDM and OFDMA are adopted, in the existing standards, the two technologies are relatively independent, and there is no cooperation for the two systems in the standard. Work is clearly defined. From the perspective of compatibility, it is necessary to study the cooperative work of OFDM system and OFDMA system, so that future systems can support both OFDM and OFDMA technologies to protect the interests of investors and users.

The IEEE 802.16 standard specifies the protocol stack structure of the base station system data/control plane, as shown in Figure 2. The protocol stack includes two parts, the MAC layer and the PHY layer. The MAC layer is further divided into a CS sublayer (Convergence Sublayer), a CPS sublayer (Common Part Sublayer), and a Security Sublayer from top to bottom in the protocol stack. Three parts. The CS sublayer is responsible for receiving the upper layer data, dividing the external network service data unit and respectively associated with the appropriate MAC traffic flow and CID (Connection Identifier) and completing the load header compression; the CPS sublayer completes system access, bandwidth allocation, resource scheduling , connection establishment and maintenance functions; security sub-layer to complete the functions of authentication, key management and encryption and decryption; physical layer to achieve data encoding and transmission and transmission.

For OFDM and OFDMA coexistence systems, the conventional protocol stack cannot meet the compatibility of OFDM and OFDMA, so the base station system structure of OFDM and OFDMA coexistence systems needs to be redesigned.

In addition, the OFDM system adopts multi-carrier technology to convert the high-speed data stream through serial-to-parallel conversion, so that the duration of the data symbols on each sub-carrier is relatively increased, so that the time dispersion of the wireless channel can be effectively reduced (ISI) (InterSymbol Interference, Inter-symbol interference), which reduces the complexity of the equalization in the receiver, and even avoids the use of an equalizer, eliminating the adverse effects of ISI only by inserting a cyclic prefix. There is orthogonality between the subcarriers of the OFDM system, which allows the spectrum of each subcarrier to overlap each other, so the OFDM system can make maximum use of the spectrum resources compared with the conventional frequency division multiplexing system.

FIG. 3 is a time domain waveform diagram of an OFDM symbol using a cyclic insertion prefix in the prior art. In Figure 3, Tb represents the effective symbol period in the OFDM signal, Tg is the inserted cyclic prefix, the content of Tg is the copy of the last part of the content in the Tb period, and Ts is the period of the entire OFDM symbol. As long as the length of the cyclic prefix is greater than the maximum delay spread of the OFDM symbol, the orthogonality of each subcarrier within an OFDM symbol will still be guaranteed. Therefore, multipath interference can be overcome by periodically inserting the cyclic prefix Tg.

The IEEE 802.16 working group uses OFDM and OFDMA techniques as implementations of fixed broadband wireless access. FIG. 4 and FIG. 5 respectively show the OFDM frame structure and the frame structure of OFDMA in the TDD (Time Division Duplex) mode in the IEEE802.16a protocol. In FIG. 4, one OFDM frame includes one downlink subframe and one uplink subframe. A downlink subframe includes only one downlink PHY PDU (Physical Protocol Data Unit). One uplink subframe includes a contention interval for initial Ranging and bandwidth requests and one or more uplink PHY PDUs, each of which is transmitted by a different terminal. The downstream PHY PDU starts with a long prefix and is used for physical layer synchronization. The prefix is followed by a FCH (Frame Control Header) burst. If a DL-MAP (Downlink Map) message is sent in the current frame, it will be the first MAC (Medium Access Control) PDU after the FCH, and the FCH is followed by one or more downlink bursts. Each burst can be transmitted using a different Burst Profile. Each downlink burst includes an integer number of OFDM symbols.

In Figure 5, an 0FDMA frame includes one downlink subframe and one uplink subframe, and the first two channels transmitted in the first data symbol of the downlink 0FDMA subframe are FCH. The Ranging subchannel indicated in the UL-MAP message is included in the uplink 0FDMA subframe for Ranging processing and bandwidth application.

In the prior art, there is no method for effectively implementing the cooperation between the OFDM system and the 0FDMA system. The most recent method is in US Pat. No. 6,567,374, "Data and pilot mapping in an OFDM system" and US 6,535,501 "Transmission method and transmission apparatus for transmitting signals on the basis of a OFDM/TDMA-system in a GSM/system". A method for mapping OFDM symbols into GSM time slots is proposed, in which the cyclic prefix and subcarrier spacing of OFDM need to be modified accordingly in order to adapt to the requirements of the GSM time slot.

Therefore, in order to enable the future system to support both 0FDM and OFDMA technologies to maximize the protection of investors and users, it is necessary to design a frame structure that satisfies the requirements of the 0FDM and OFDMA coexistence systems and the base station that implements the frame structure. The system, in turn, is compatible with OFDM and OFDMA systems. Invention disclosure

The main object of the present invention is to provide an OFDM and OFDMA coexistence system and a cooperative working method thereof, which ensures compatibility of the air interface with the two systems by constructing a reasonable frame format, and implements OFDM and OFDMA through a reasonable base station structure. The construction of the frame structure of the coexistence system, and thus the compatibility of OFDM and OFDMA and the realization of two different time systems of OFDM and OFDMA Work together to maximize the protection of the interests of investors and users.

In order to achieve the above object, the present invention proposes a coexistence system of OFDM and OFDMA, which is characterized in that it comprises:

At least one terminal of the OFDM or OFDMA system, configured to receive downlink information from the base station system and send uplink information according to the indication of the base station;

a base station system, configured to receive uplink information from an OFDM or OFDMA system terminal and send corresponding downlink information, where the base station system further includes:

a MAC layer, configured to receive data from an OFDM or OFDMA system terminal, and construct a frame structure in which OFDM and OFDMA coexist in a time division manner by OFDM and OFDMA data in the same frequency band, and distribute the frame structure to the physical layer;

A physical layer includes an OFDM physical layer module and an OFDMA physical layer module, configured to separately code and modulate OFDM or OFDMA data and transmit according to resources allocated by the MAC layer.

The foregoing OFDM and OFDMA coexistence system is characterized in that the MAC layer of the base station system has a dual MAC structure, which includes:

Separate OFDM MAC layer modules and OFDMA MAC layer modules for respectively receiving and processing OFDM and OFDMA data to complete all functions of the legacy MAC layer;

The lower layer adaptation module is respectively connected to the OFDM MAC layer module, the OFDMA MAC layer module and the OFDM physical layer module and the OFDMA physical layer module located at the upper layer thereof, and is used for completing system mixed frame construction, resource allocation, and data. Transmission and other functions.

The foregoing OFDM and OFDMA coexistence system is characterized in that the MAC layer further includes an upper layer adaptation module, configured to separately distribute the upper layer data packets to the OFDM MAC layer module or the OFDMA MAC layer module according to the receiving object.

The foregoing OFDM and OFDMA coexistence system is characterized in that the MAC layer distributes the upper layer data packets to the OFDM MAC layer module or the OFDMA MAC layer module according to the receiving object through the router outside the base station system.

The foregoing OFDM and OFDMA coexistence system is characterized in that the lower layer adaptation module performs all information interactions with the MAC layer module and the physical layer module, including data and related resource scheduling messages.

The foregoing OFDM and OFDMA coexistence system is characterized in that the lower layer adaptation module Only the related resource scheduling messages are exchanged with the MAC layer module and the physical layer module, and the data interaction is directly performed between the MAC layer module and the physical layer module.

The foregoing OFDM and OFDMA coexistence system is characterized in that: the OFDM MAC layer module is composed of an OFDM CS sublayer module, an OFDM CPS sublayer module, and an OFDM security sublayer module that are sequentially connected; the OFDMA MAC layer module The OFDM A CS sublayer module, the OFDMA CPS sublayer module, and the OFDMA security sublayer module are sequentially connected, wherein

The OFDM CS sublayer module and the OFDMA CS sublayer module are respectively used to perform classification and packing of OFDM and OFDMA data processed by the upper layer adaptation module;

The OFDM CPS sublayer module and the OFDMA CPS sublayer module are respectively configured to process data output by the OFDM CS sublayer module and the OFDMA CS sublayer module, and construct a frame structure capable of realizing OFDM and OFDMA coexistence in a time division manner, and complete the system. Core MAC functions, including system access, bandwidth allocation, resource scheduling, connection establishment and maintenance;

The OFDM security sublayer module and the OFDMA security sublayer module are respectively configured to process data outputted by the OFDM CPS sublayer module and the OFDMA CPS sublayer module, and implement functions such as system authentication, key management, and data encryption and decryption.

The foregoing OFDM and OFDMA coexistence system is characterized in that the MAC layer of the base station system adopts a converged MAC structure, including:

a CS sublayer module for uniformly classifying and packing OFDM and OFDMA data;

An OFDM CPS sub-layer non-reuse module and an OFDMA CPS sub-layer non-reuse module for separately processing OFDM and OFDMA data output by the CS sub-layer module, and implementing a non-reusable portion of the CPS processing of OFDM and OFDMA;

The CPS reuse module is configured to uniformly process the OFDM and OFDMA data output by the CS sublayer module, and implement the processing of the reusable part and the uniform resource scheduling part in the CPS processing of the OFDM and the OFDMA;

The security sublayer module is connected to the OFDM CPS sublayer non-reuse module, the OFDMA CPS sublayer non-reuse module, and the CPS reuse module, and is used for unified authentication, key management, data encryption and decryption, etc. of the OFDM and OFDMA systems. The management function is connected to the OFDM physical layer module and the OFDMA physical layer module, and is configured to distribute the processed data to the OFDM physical layer module and the OFDMA physical layer module.

The foregoing OFDM and OFDMA coexistence system is characterized in that the base station system uses a stack Additive structure, including independent

An OFDM base station system, configured to receive uplink information from an OFDM system terminal and transmit corresponding downlink information thereto; the OFDM base station system includes an OFDM MAC sublayer module of a MAC layer and an OFDM physical layer module of a physical layer;

An OFDMA base station system, configured to receive uplink information from an OFDMA system terminal and send corresponding downlink information thereto; the OFDMA base station system includes an OFDMA MAC sublayer module of a MAC layer and an OFDMA physical layer module of a physical layer;

The OFDM base station system and the OFDMA base station system exchange information at the MAC layer through the interface to determine the transmission order of the two base station systems.

In order to achieve the above object, the present invention also provides a method for cooperative operation of an OFDM and OFDMA coexistence system, which is applied to a coexistence system of OFDM and OFDMA, the coexistence system comprising at least one terminal of OFDM or OFDMA system, and a base station system The feature is that the method includes the following steps:

The base station system constructs the OFDM and OFDMA data of the same frequency band into a frame structure capable of coexisting OFDM and OFDMA in a time division manner, including respective uplink and downlink subframes;

The base station system sets the overhead information of the OFDMA and the OFDM respectively, and the allocation information of the respective uplink and downlink subframes is indicated in the overhead information;

The base station system sends downlink data such as synchronization information, overhead information, and load in the OFDMA downlink subframe according to the requirements of the OFDMA system, and sends downlink information such as synchronization information, overhead information, and load in the OFDM downlink subframe according to the requirements of the OFDM system;

The terminal receives the downlink synchronization information and the overhead information of the corresponding system, implements downlink synchronization with the base station, and acquires allocation information of the corresponding uplink and downlink subframes;

The terminal receives the downlink load data at the location specified by the base station according to the received overhead information. The terminal sends the uplink data at the location specified by the base station according to the received overhead information.

The foregoing method for cooperating OFDM and OFDMA coexistence systems is characterized in that the process of constructing a coexistence frame structure by the base station system includes the following steps:

The base station divides the frame into two parts on the time axis, one part is used for transmitting the downlink subframe, and the other part is used for receiving the uplink subframe;

The base station divides the downlink subframe into two parts on the time axis, one part is used for transmitting the OFDMA downlink subframe, and the other part is used for transmitting the OFDM downlink subframe; The base station divides the uplink subframe into two parts on the time axis, one part for transmitting the OFDMA uplink subframe and the other part for transmitting the OFDM uplink subframe.

The foregoing method for cooperating the OFDM and the OFDMA coexistence system is characterized in that: part of the OFDM uplink or downlink subframe may be used for the OFDMA uplink or downlink subframe as needed, and part of the OFDMA uplink or downlink subframe may also be used. Lend to OFDM uplink or downlink subframes as needed.

The above method for cooperating OFDM and OFDMA coexistence systems is characterized in that the process of constructing a coexistence frame structure by the base station system comprises the following steps: the base station divides the frame into two parts on the time axis, one part for transmitting the OFDMA frame, and the other part for transmitting the OFDMA frame, and the other part Used to transmit OFDM frames;

The base station divides the OFDMA frame into two parts on the time axis, one part is used for transmitting the OFDMA downlink subframe, and the other part is used for receiving the OFDMA uplink subframe;

The base station divides the OFDM frame into two parts on the time axis, one for transmitting the OFDM downlink subframe and the other for receiving the OFDM uplink subframe.

The foregoing method for cooperating OFDM and OFDMA cooperating systems is characterized in that a part of the OFDM subframe can be used for the OFDMA subframe as needed, and a part of the OFDMA subframe can also be borrowed for the OFDM subframe as needed.

The base station divides the frame into two parts on the time axis, one part is used for transmitting the OFDMA downlink subframe, and the other part is used for receiving the OFDMA uplink subframe;

The base station allocates a region in the OFDMA downlink subframe for transmitting the OFDM downlink subframe. The base station allocates a region in the OFDMA uplink subframe for receiving the OFDM uplink subframe. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a block diagram of an existing OFDM system;

2 is a schematic diagram of a protocol structure on a system data/control plane in the IEEE802.16 standard in the prior art;

3 is a time domain waveform diagram of an OFDM signal with a cyclic prefix added in the prior art;

4 is a schematic structural diagram of an OFDM frame in the prior art; FIG. 5 is a schematic structural diagram of an OFDMA frame in the prior art; FIG.

6 is a schematic diagram of a frame structure of a time division system commonly used in the prior art;

7A is a schematic diagram of a frame structure of a first embodiment of a method for cooperatively operating an OFDM and OFDMA coexistence system according to the present invention;

7B is a schematic diagram of another frame structure of a first embodiment of a method for cooperatively operating an OFDM and OFDMA coexistence system according to the present invention;

8 is a schematic diagram of a frame structure of a second embodiment of a method for cooperatively operating an OFDM and OFDMA coexistence system according to the present invention;

9 is a schematic diagram of a frame structure of a third embodiment of a method for cooperatively operating an OFDM and OFDMA coexistence system according to the present invention;

10A is a schematic structural diagram of a base station system having a dual MAC structure in a first embodiment of a frame for implementing an OFDM and OFDMA coexistence system according to the present invention;

FIG. 10B is another schematic structural diagram of a base station system with dual MAC structure according to a first embodiment of an OFDM and OFDMA coexistence system according to the present invention; FIG.

11 is a schematic structural diagram of a base station system having a fused MAC structure according to a second embodiment of the OFDM and OFDMA coexistence system of the present invention;

12 is a schematic structural diagram of a superposed base station system according to a third embodiment of the OFDM and OFDMA coexistence system of the present invention;

13A is a schematic diagram of a network structure of an alternative base station according to the present invention;

13B is a schematic structural diagram of a superposed base station network according to the present invention;

FIG. 13C is a schematic diagram of another superposed base station network architecture according to the present invention. The best way to implement the invention

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

The frame structure of a common time division system is as shown in FIG. 6. One frame includes one downlink subframe and one uplink subframe, and the uplink or downlink subframe includes multiple slots for data transmission, downlink subframes and uplink subframes. The transition interval between them is called a TGW (transition transition gap), and the transition interval between an uplink subframe and a downlink subframe is called RTG (receive transition gap).

Due to the significant difference in implementation between OFDM and OFDMA techniques, it is difficult to directly achieve compatibility between physical layers. But since both systems are time division systems, when OFDM and OFDMA systems Using the same frequency band day t, they can achieve coexistence in the frame structure in a time division manner. 7A, 7B and 8, and 9 show the system frame structure of three simultaneously compatible OFDM and OFDMA terminals. [Note: These three frame configurations are applicable to the base station systems of the three configurations described later.) The following description will be respectively made.

As shown in FIG. 7A, in the first frame structure, a frame is first divided into a downlink subframe and an uplink subframe, and the uplink/downlink subframes are respectively combined by the OFDMA subframe and the OFDM subframe in a time division manner. Thus, for example, as shown in Fig. 7A. The downlink subframe is divided into an OFDMA downlink subframe and an OFDM downlink subframe, and the uplink subframe is divided into an OFDMA uplink subframe and an OFDM uplink subframe. For an OFDMA terminal, it sees a complete OFDMA frame. The time slot occupied by the OFDM downlink subframe can be regarded as part of the TTG in the OFDMA frame or an area already allocated in the OFDMA downlink subframe. The OFDM uplink subframe The occupied time slot can also be regarded as a part of the RTG in the OFDMA frame or an area already allocated in the OFDMA uplink subframe. The area occupied by the TTG, RTG or OFDM subframe may be indicated in the overhead message in the OFDMA subframe. For an OFDM terminal, it also sees a complete OFDM frame. The time slot occupied by the OFDMA uplink subframe can be regarded as a part of the TTG in the OFDM frame or an area already allocated in the OFDM downlink subframe. The OFDMA downlink subframe The occupied time slot can be seen as part of the RTG in the OFDM frame. The time slot occupied by the TTG or OFDMA subframe may be indicated in the overhead message in the OFDM subframe. The communication process of the OFDM or OFDMA terminal is exactly the same as the conventional method. They can obtain the starting position of the downlink frame by searching the prefix, and obtain the starting position of the uplink frame by using the overhead message.

If there are few OFDM users, in order to improve the spectrum utilization efficiency, a part of the uplink and downlink OFDM subframes may be used for the transmission of OFDMA data. At this time, FIG. 7A becomes FIG. 7B, and the OFDM and OFDMA terminals are processed at this time. Similar to the previous description. In the example of FIG. 7A, the position of the OFDMA subframe and the position of the OFDM subframe are also interchangeable, and the processing manner of the terminal is basically the same as that of the foregoing, and will not be described in detail herein. The advantage of this embodiment is that the OFDMA subframe and the OFDM subframe are completely independent, and the communication requirements of the OFDMA and the OFDM system can be satisfied simultaneously without changing the implementation of the two systems.

In the second frame structure, an OFDM subframe and an OFDMA subframe are combined in a time division manner in one frame. As shown in FIG. 8, one frame includes one OFDM subframe and one OFDMA subframe, and one OFDM subframe includes one lower if. An OFDM subframe and an uplink OFDM subframe, one OFDMA subframe includes one downlink OFDMA subframe and one uplink OFDMA subframe. For OFDM terminals, it looks A complete OFDM frame is obtained. The time slot occupied by the OFDMA subframe is regarded as a part of the RTG in the OFDM frame or the burst allocated by the uplink OFDM subframe. The time slot occupied by the RTG or OFDMA subframe is determined by the OFDM system. Opening the message instructions. For an OFDMA terminal, it also sees a complete OFDMA frame. The time slot occupied by the OFDM subframe can be regarded as part of the RTG in the OFDMA frame or the burst allocated by the uplink OFDMA subframe, occupied by the RTG or OFDM subframe. The time slot is indicated by the overhead message of the OFDMA system. The difference between this embodiment and the above-mentioned first embodiment lies in the overhead of requiring additional uplink/downlink conversion time between the upper fi downlink subframes of OFDM or OFDMA. The OFDM sub-frame and the OFDMA subframe of this embodiment may also be interchanged, that is, the OFDMA subframe is first, and the OFDM subframe is after, because there is no difference in implementation and processing, and no further description is made.

In the third frame structure, the data area (excluding the prefix) in the OFDMA uplink/downlink frame is divided into a continuous frequency band for the uplink/downlink frame transmission of the OFDM system, and the position of the OFDM frequency band in the OFDMA band can be based on actual conditions. The situation is adjusted. As shown in FIG. 9, the OFDM subframe and the OFDMA subframe respectively have their own independent uplink and downlink subframes. In order to prevent OFDM data and OFDMA data from interfering with each other, a certain guard band needs to be allocated around the OFDM subframe frequency band. This scheme is applicable to the case where the OFDM system and the OFDMA system use the same frequency band but different bandwidths and the OFDMA system adopts the continuous subcarrier allocation mode. In this embodiment, the OFDMA system actually plays the role of the OFDM data bearer. The advantage of this embodiment is that when the bandwidths of the two systems are different, the spectrum utilization is high. The disadvantage is that when the OFDMA subcarriers adopt the discontinuous division mode, the system cannot implement the system.

For all frame structures, depending on the actual situation of the OFDM system (such as different requirements of resource utilization and implementation complexity), the above different OFDMA frame structures can be selected to ensure that the upgraded OFDMA system satisfies both OFDM simultaneously. Communication requirements with OFDMA terminals.

For a coexistence system of OFDM and OFDMA, a reasonable frame format guarantees the compatibility of the air interface to the two systems. In addition, it is necessary to design a reasonable base station structure to realize the coexistence system frame of OFDM and OFDMA.

In the present invention, the OFDM and OFDMA coexistence system includes: at least one OFDM or OFDMA terminal for receiving downlink information from a base station system and transmitting uplink information according to a base station indication; and a base station system for receiving from Uplink information of an OFDM or OFDMA system terminal and transmitting corresponding downlink information, the base station system includes: a MAC layer, used for Receiving data from an OFDM or OFDMA system terminal, processing the OFDM or OFDMA data separately, and distributing the processed data to the physical layer; and a physical layer including the OFDM physical layer module and the OFDMA physical layer module, The OFDM or OFDMA data is separately coded and transmitted and transmitted according to resources allocated by the MAC layer.

As described above, in order to achieve compatibility with OFDM and OFDMA systems in the frame format, the OFDM and OFDMA coexistence systems can adopt the following three structures:

In the first configuration, the base station system adopts a dual MAC structure. As shown in FIG. 10A or FIG. 10B, the base station system includes the following modules:

The upper layer adaptation module is configured to separately distribute the upper layer data packet to the OFDM CS sublayer module or the OFDMA CS sublayer module according to the receiving object. In a specific case, the module can also be implemented by a router outside the base station, and the base station system will not include the module;

An OFDM CS sublayer module and an OFDMA CS sublayer module, which are used to perform classification and packing of OFDM and OFDMA data processed by the upper layer adaptation module;

An OFDM CPS sublayer module and an OFDMA CPS sublayer module, which are respectively used to process data output by the OFDM CS sublayer module and the OFDMA CS sublayer module, respectively (Note: the construction of the frame structure is performed in the CPS sublayer module, Not implemented in the CS layer) They complete the core MAC functions of the system, such as system access, bandwidth allocation, resource scheduling, connection establishment and maintenance, etc.

OFDM security sublayer module and OFDMA security sublayer module, which are respectively used to process data outputted by the OFDM CPS sublayer module and the OFDMA CPS f layer module, which implement system authentication, key management, and data encryption and decryption. Waiting for

A lower layer adaptation module, which is followed by an OFDM Security Sublayer Module and an OFDMA Security Sublayer Module. Responsible for completing system mix frame construction, resource allocation, data transfer and other functions;

An OFDM physical layer module and an OFDMA physical layer module, where the layer is used for coding and modulating OFDM and OFDMA data respectively, and transmitting according to resources allocated by the lower layer adaptation module;

The processing of the upper layer data packet by the upper layer adaptation module is respectively sent to the OFDM CS sublayer module or the OFDMA CS sublayer module for processing according to the receiving object. The data processed by the OFDM CPS sublayer module and the security sublayer module or the OFDMA CPS sublayer module and the security sublayer module are processed by the lower layer adaptation module to complete the functions of mixed frame construction, resource allocation and scheduling, data transmission, etc., and then pass through OFDM respectively. The physical layer module or the OFDMA physical layer module performs code modulation and transmits, as shown in FIG. 10A. The information flow between the modules in Figure 10A is represented by the arrows shown in the figure, the module The information flow between the data stream sent by the uplink and the downlink and the message stream of the 5: between the modules. In order to reduce the processing load of the lower layer adaptation module, the dual MAC structure shown in FIG. 10A can also be changed to that shown in FIG. 10B. In FIG. 10B, the information flow between the modules includes three types, and 2 is data and messages. Information flow, 3 is the data stream, and 4 is the message stream. The interaction between the lower layer adaptation module and the OFDM MAC layer module, the OFDMA MAC layer module, the OFDM physical layer module, and the OFDMA physical layer module is only a message flow for resource allocation and scheduling, and the OFDM MAC layer module or the OFDMA MAC layer The data stream output by the module is sent directly to the OFDM physical layer module or the OFDMA physical layer module. In the base station system of the structure, there is a completely independent OFDM corresponding processing module and an OFDMA corresponding processing module, so the implementation is relatively simple.

In the second structure, the base station system adopts a converged MAC structure. As shown in Fig. 11, the base station system includes the following modules:

CS sub-layer module, which is used for uniformly classifying and packaging OFDM and OFDMA data;

OFDM CPS sub-layer non-reuse module and OFDMA CPS sub-layer reuse module; the two modules respectively process OFDM and OFDMA data output by the CS sub-layer module, which implement a part of the difference between CPS processing of OFDM and OFDMA;

CPS reuse module, which uniformly processes the CS sub-layer module output S J OFDM and OFDMA data, and the reuse module combines the same part of OFDM and OFDMA in CPS processing and the part of unified resource scheduling;

Security sublayer module, which is used to uniformly implement functions such as authentication, key management, and data encryption and decryption of OFDM and OFDMA systems;

An OFDM physical layer module and an OFDMA physical layer module, which are used to separately code and modulate OFDM and OFDMA data and transmit according to resources allocated by the CPS reuse module.

The upper layer data is processed by the unified CS sublayer module and then processed to perform corresponding CPS processing. The reusable parts (such as resource allocation and scheduling) in the CPS processing are uniformly processed in the CPS reuse module, and the non-reusable parts in the CPS processing are processed. It is processed by the OFDM CPS sublayer non-reuse module and the OFDMA CPS sublayer non-reuse module, respectively. The security sublayer module performs unified encryption, decryption and security management on the data output by the OFDM CPS sublayer non-reuse module and the OFDMA CPS sublayer non-reuse module. The OFDM physical layer module and the OFDMA physical layer module are separately transmitted according to the scheduling information in the CPS reuse module. The base station system that combines the MAC structure maximizes the reuse between the OFDM and OFDMA modules, and fuses the same modules or modules that require joint scheduling. For modules with large differences, such as some MAC messages, they are processed separately, so they are more efficient.

In the third embodiment, the base station system may also adopt a structure of a superposition manner, as shown in FIG. 12, including an OFDM base station system, configured to receive uplink information from an OFDM system terminal and send corresponding downlink information thereto; a base station system, configured to receive uplink information from an OFDMA standard terminal and send corresponding downlink information thereto. The OFDM system and the OFDMA system are independent of each other, and have a certain interface (there is no special requirement for the interface, as long as the interaction of the relevant parameters is completed) to meet the needs of the interaction between the MAC layer of the OFDM system and the MAC layer of the OFDMA system. The order of transmission of the two base station systems is determined. The MAC layer includes a CS, a CPS, and a security sublayer module, and the process of constructing the frame structure is implemented in the CPS. The information exchanged by the interface mainly includes the start and end slots of the OFDM subframe, the start junction slot of the OFDMA subframe, and the like. The information interaction between the OFDM system and the OFDMA system can also be guaranteed by the setting in the background, but this method is less flexible in implementation.

For the above three implementation manners, there may be two base station networking modes, that is, a replacement network architecture and a superimposed network architecture.

The area of the network architecture of the base station of the dual MAC structure and the base station of the fused MAC structure is only the internal implementation of the base station system, and can be represented by Fig. 13A. 11 is an OFDM terminal, 12 is an OFDMA terminal, and 13 is a base station system with a dual MAC structure or a fused MAC structure. For a base station system with dual MAC structure, the data sent to 11 and 12 is processed by two completely independent systems after being easily distinguished by the adaptation layer. For a base station system with a converged MAC structure, the data sent to 11 and 12 is uniformly processed by 13, and the time-sharing transmission of OFDM and OFDMA data is realized by the CPS reuse module therein.

For a base station system employing a superimposed structure, there are two possible implementations of the network architecture, as shown in Figures 13B and 13C. In FIG. 13B, 21 is an OFDM terminal, 22 is an OFDM terminal, 23 is a base station system of OFDM; 24 is a base station system of OFDMA, where 23 and 24^; two separate entities can be placed in the same location, 23 and 24 The core network is independently accessed to support different terminals 21 and 22, and the interface between 23 and 24 completes the message interaction between 23 and 24 to form a timing match on the transmission of the OFDM base station and the OFDMA base station. In Fig. 13C, 31 is an OFDM terminal, 32 is an OFDMA terminal, 33 is a base station system of OFDM; and 34 is a base station system of OFDM. The difference between FIG. 13B and FIG. 13C is that the base station 33 does not directly access the core network, and the base station The interface between the network 33 and the base station 34 requires both simple information interaction and data transmitted by the base station 33 to the core network. Therefore, in the two implementation manners, the design of the interface should have different requirements.

According to the actual situation of the OFDM and OFDMA coexistence system, the above different base station system structure and network architecture implementation manner are selected, and the system can be conveniently compatible with the OFDM system and the OFDMA system.

In combination with the above-described frame structure and base station system of the OFDM and OFDMA coexistence system, the method of cooperating the coexistence systems of the present invention will be described in detail below.

Method one includes the following steps:

The base station divides the downlink subframe into two parts on the time axis, one part is used for transmitting the OFDMA downlink subframe, and the other part is used for transmitting the OFDM downlink subframe, wherein part of the OFDM uplink or downlink subframe can be loaned to the OFD.MA uplink as needed. Or the downlink subframe is used, and part of the OFDMA uplink or downlink subframe may also be used for OFDM uplink or downlink subframes as needed;

The base station divides the uplink subframe into two parts on the time axis, one part is used for transmitting the OFDMA uplink subframe, and the other part is used for transmitting the OFDM uplink subframe;

The base station sets the overhead information of OFDMA and OFDM respectively, and indicates the allocation of the respective uplink and downlink subframes in the overhead information;

The base station transmits downlink data such as synchronization information, resale information, and load according to the requirements of the OFDMA system in the OFDMA downlink subframe, and transmits downlink information such as synchronization information, overhead information, and load in the OFDM downlink subframe according to the requirements of the OFDM system;

Method two, including the following steps:

The base station divides the frame into two parts on the time axis, one part for transmitting the OFDMA frame and the other part for transmitting the OFDM frame;

The base station divides the OFDMA frame into two parts on the time axis, one part is used for transmitting the OFDMA downlink subframe, and the other part is used for receiving the OFDMA uplink subframe; The base station divides the OFDM frame into two parts on the time axis, one part is used for transmitting the OFDM downlink subframe, and the other part is used for receiving the OFDM uplink subframe; wherein, part of the OFDM subframe can be borrowed for the OFDMA subframe as needed, the OFDMA sub- A part of the frame may also be borrowed for use by the OFDM subframe as needed;

The base station sets the overhead information of the OFDMA and the OFDM according to the allocation of the frame, and indicates the allocation of the uplink and downlink subframes in the overhead information;

The base station sends downlink data such as synchronization information, sales information, and load in the OFDMA downlink subframe according to the requirements of the OFDMA system;

The base station transmits downlink data such as synchronization information, overhead information, and load in the OFDM downlink subframe according to the requirements of the OFDM system;

Method three includes the following steps:

The base station allocates a region in the OFDMA downlink subframe for transmitting the OFDM downlink subframe. The base station allocates a region in the OFDMA uplink subframe for receiving the OFDM uplink subframe. The base station sets the overhead information of the OFDMA according to the allocation of the frame, and indicates the allocation of the uplink and downlink subframes in the overhead information in the overhead information;

The base station sets the OFDM overhead information according to the allocation of the frame, and specifies the allocation of the OFDM uplink and downlink subframes in the overhead information.

The part of the base station allocated to the OFDMA system in the downlink subframe transmits downlink data such as synchronization information, overhead information, and load according to the requirements of the OFDMA system;

The part of the OFDM system allocated by the base station in the downlink subframe transmits downlink data such as synchronization information, overhead information, and load according to the requirements of the OFDM system;

Receiving downlink load data at a location specified by the base station according to the received overhead information; The terminal transmits the uplink data at the location specified by the base station according to the received overhead information.

There are a variety of other embodiments of the present invention, and various modifications and changes can be made thereto in accordance with the present invention without departing from the spirit and scope of the invention. Changes and modifications are intended to be included within the scope of the appended claims. Industrial applicability

With the design of the present invention, compatibility with OFDM and OFDMA systems can be achieved without changing the specific implementation of OFDM and OFDMA;

Through the design of the invention, the OFDMA system can be easily upgraded and compatible with the OFDM terminal;

With the design of the present invention, the backward compatibility of the OFDM system can be maintained after the OFDM system is upgraded to the OFDMA system, thereby protecting the interests of the operator and the user;

Through the design of the present invention, networking of OFDM and OFDMA coexistence systems can be realized.

Claims

Claim

A coexistence system of OFDM and OFDMA, comprising:

a MAC layer, configured to receive data from an OFDM or OFDMA system terminal, construct a frame structure that can realize OFDM and OFDMA coexistence in a time division manner by OFDM and OFDMA data in the same frequency band, and distribute the frame structure to the physical layer;

2. The OFDM and OFDMA coexistence system according to claim 1, wherein the MAC layer of the base station system has a dual MAC structure, and the method includes:

The OFDM and OFDMA coexistence system according to claim 2, wherein the MAC layer further comprises an upper layer adaptation module, configured to separately distribute the upper layer data packets to the OFDM MAC layer module or the OFDMA MAC according to the receiving object. Layer modules are processed.

The OFDM and OFDMA coexistence system according to claim 2, wherein the MAC layer distributes the upper layer data packet to the OFDM MAC layer module or the OFDMA MAC layer module according to the receiving object by using a router outside the base station system. deal with.

The OFDM and OFDMA coexistence system according to claim 2 or 3 or 4, wherein the lower layer adaptation module performs all information interactions between the MAC layer module and the physical layer module, including data and correlation. Resource scheduling message.

6. The coexistence system of OFDM and OFDMA according to claim 2 or 3 or 4, The interaction between the lower layer adaptation module and the MAC layer module and the physical layer module is performed only on the related resource scheduling message, and the data interaction is directly performed between the MAC layer module and the physical layer module.

The OFDM and OFDMA coexistence system according to claim 3, wherein the OFDM MAC layer module is composed of an OFDM CS sublayer module, an OFDM CPS sublayer module, and an OFDM security sublayer module that are sequentially connected; The OFDMA MAC layer module is composed of an OFDM A CS sublayer module, an OFDMA CPS sublayer module, and an OFDMA security sublayer module, which are sequentially connected, where

The OFDM CPS sub-layer module and the OFDMA CPS sub-layer module are respectively configured to process data output by the OFDM CS sub-layer module and the OFDMA CS sub-layer module, and construct a frame structure capable of realizing OFDM and OFDMA coexistence in a time division manner, and complete the system. Core MAC functions, including system access, bandwidth allocation, resource scheduling, connection establishment and maintenance;

The OFDM and OFDMA coexistence system according to claim 1, wherein the MAC layer of the base station system adopts a fused MAC structure, and includes:

a CS sublayer module for uniformly classifying and packing OFDM and OFDMA data; an OFDM CPS sublayer non-reuse module and an OFDMA CPS sublayer non-reuse module for respectively processing OFDM and OFDMA data output by the CS sublayer module, OFDM and OFDMA

Processing of parts that are not reusable in CPS processing;

The CPS reuse module is configured to uniformly process the OFDM and OFDMA data transmitted by the CS sublayer module, and implement the processing of the reusable part and the uniform resource scheduling part of the CPS processing of the OFDM and the OFDMA;

9. The OFDM and OFDMA coexistence system according to claim 1, wherein the base station system adopts a superimposed structure, including independent of each other.

10. A method for cooperative operation of an OFDM and OFDMA coexistence system, applied to a coexistence system of OFDM and OFDMA, the coexistence system comprising at least one terminal of OFDM or OFDMA system, and a base station system; characterized in that the method comprises The following steps:

The method for cooperating OFDM and OFDMA coexistence systems according to claim 10, wherein the process of constructing the coexistence frame structure by the base station system comprises the following steps:

The OFDM and OFDMA coexistence system cooperatively working according to claim 11, wherein a part of the OFDM uplink or downlink subframe can be used for an OFDMA uplink or downlink subframe, OFDMA uplink or A part of the downlink subframe may also be used for OFDM uplink or downlink subframes as needed.

The method for cooperating OFDM and OFDMA coexistence systems according to claim 10, wherein the process of constructing the coexistence frame structure by the base station system comprises the following steps: the base station divides the frame into two parts on the time axis, and the part is used The OFDMA frame is transmitted, and the other part is used to transmit an OFDM frame;

The base station divides the OFDMA frame into two parts on the time axis, one part is used for transmitting the OFDMA downlink sub-frame, and the other part is used for receiving the OFDMA uplink subframe;

The method for cooperating OFDM and OFDMA coexistence systems according to claim 13, wherein a part of the OFDM subframe can be borrowed for use in an OFDMA subframe, and a part of the OFDMA subframe can also be used as needed. Borrowed for use in OFDM subframes.

The base station allocates a region in the OFDMA downlink subframe for transmitting the OFDM downlink subframe. The base station allocates a region in the OFDMA uplink subframe for receiving the OFDM uplink subframe.