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TDD framing method for physical layer of wireless system

A wireless system, physical layer technology, applied in the direction of radio transmission system, transmission system, radio/induction link selection arrangement, etc., can solve problems such as orthogonal characteristic destruction, signal asynchrony, and increase system complexity.

Inactive Publication Date: 2002-12-11
LINKAIR COMM
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  • Abstract
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Problems solved by technology

This greatly increases the complexity of the system
[0007] Existing CDMA wireless systems use pseudo-random spreading codes that result in non-zero interference
Even when using orthogonal spreading codes such as Walsh codes that give zero interference, the orthogonality properties are corrupted by the presence of multipath signals from the same remote unit or by desynchronization of signals from different remote units, cause interference between different signals

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  • TDD framing method for physical layer of wireless system
  • TDD framing method for physical layer of wireless system
  • TDD framing method for physical layer of wireless system

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Embodiment Construction

[0028] figure 1 It is the frame structure of UTRA TDD, which is defined in the 3GPP specification. figure 2 is the frame structure of TD-SCDMA, which is defined in the 3GPP specification. While the TDD frame according to the present invention can be designed to conform to UTRA TDD with a chip rate of 1.28 Meps, it will have a similar frame structure with multiple switching points.

[0029] For the system design of CDMA TDD, the frame structure is one of the key factors. Some of the main factors involved are capacity, coverage, flexibility and compatibility, each of which is explained below.

[0030] Capacity is suppressed by disturbances. The result of these sources of interference is a negative impact on system performance and capacity. Various methods have been tried to reduce these disturbances. For example, in UTRA TDD and TD-SCDMA, joint detection is used to reduce inter-symbol interference (ISI) and multiple access interference (MAI), and smart antennas are also us...

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Abstract

A time division duplex framing method for the physical layer of a wireless system, wherein each frame includes a plurality of DPCH short frame structures and at least one CCPCH short frame structure. The short frame structure of each DPCH can be allocated to uplink or downlink, and contains a plurality of time slots, and the number of the time slots can be determined by the number of pulses of an LA code, the time slots The length of the slot varies with the pulse interval of the LA code, and each time slot can be modulated by a selected orthogonal spreading code. The short frame structure of the CCPCH may be allocated to the downlink in the even / odd frame, and allocated to the uplink in the odd / even frame. The method of the invention can greatly reduce adjacent cell interference (ACI), the requirement for the number of spreading codes, and the requirement for the length of spreading codes in a wireless system. At the same time, it can ideally support mobile IP services.

Description

technical field [0001] The present invention relates generally to wireless communication systems, and in particular to a method for providing a frame structure for Time Division Duplex (TDD) mode, which can provide higher capacity in mobile communication services, especially in IP-type services and performance. Background technique [0002] Today, mobile communication has become one of the important factors affecting our way of life. It can be predicted that the future communication network will be a "mobile IP" network. [0003] As far as "mobile" is concerned, the key is to support higher spectral efficiency and higher mobile speed. For "IP", the key is to support uneven business volume, higher throughput and lower delay. [0004] We already know that multiple access technology and duplex technology are the key technologies of system design. FDD FDMA is used in 1st generation systems. FDD TDMA and FDD CDMA are used in second generation systems. In the proposed 3rd ge...

Claims

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Application Information

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IPC IPC(8): H04B1/707H04B7/26H04Q7/38
CPCH04B1/7097H04B7/2618H04B2201/70702
Inventor 李道本张永生
Owner LINKAIR COMM
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