SDR moves towards the military field
The appearance of SDR originated from such a cognition, namely turned to the technical single hardware platform of many kinds of radio of processaable, the cost will not be higher than adopting the independent radio to be designed for reaching the least cost of single application, this is the result of can be expectedding. People expect a multi-functional platform can bring prominent scale economy, increase the radio function, and make the army liberate from the constraint that the patent realizes out. The cost-effective of SDR comes from an assumption, namely the expenses which maintain the simplex radio platform are lower than managing by a plurality of platforms. Certainly, ASIC possesses in employing in enormous quantities and is superior to FPGA and cost advantage that DSP realizes. However, when considering a plurality of platforms, the lasting reducing of FPGA and DSP cost, and the reusability of the software, advantage these can offset many pieces of development and maintenance cost of ASIC.
It is military behind the scale economic SDR and business application motive force is to lower costs. The army hopes to realize this goal through reducing the total radio quantity which must be supported in a design. Look from commercial angle, SDR is less likely to pay close attention to supporting many kinds of radiotechnics, but hope to lighten design and development, increase the reliability of the radio through extensive grade, and can make the framework of future generation accomplish IP (intellectual property right) on the basis of realizing before Put in an position. At present, the army should support more than 30 agreements. These agreements have used a series of encrypting and Africa's encrypted waveform. The driving force that SDR popularizes and develops in the army is JTRS (unite the radio system of tactics) . SDR of JTRS make great efforts, aim at, popularize ready-made the intersection of software and hardware and usability of part, make singly implementing, can deal with many kinds of waveform of agreement, the goal is optimal power consumption, characteristic and cost too. In the commercial field, support the value of many agreements to be lower than the military field. Generally, there are only drib agreements in an application in the competition. It is mainly two respects, namely honeycomb and safety not to the military application pay close attention to SDR technology. In honeycomb, support many kinds of radiotechnics (such as GSM and CDMA) base station with cellular network for capacity,be lasted the ones potential operation income. As to safe application ' For example police and fire fighter use different radio) ,A kind of general radio will dispel the trouble that everybody carry the ability communications and liaison of many kinds of radio. How these prospects have changed the trade notably to think about. For example, a global telephone usability that can be used on any frequency band is limited, market share is very low too. What the army hoped is to unify, but the business circles seeks to design simply and effectively. The ultimate goal of the future SDR of SDR is to set up such a radio, waited a moment and can be programmed in its frequency, intermediate frequency, base band, modulating, the agreement, frequency hopping. A typical radio realizes that should fix these characteristic majorities to come down, therefore limit it. Real SDR makes great efforts to revise all these parameters. Present SDR realize, still have long ways from the intersection of marketing and common radio of ideal that managers imagined. Today, most radio realizes the radio frequency part by ASIC, but the forward end is directed against particular application. The general forward end which covers a plurality of frequency bands and frequency can be revised with the software, but it has not appeared yet. In addition, the operating personnel must send the radio back to the producer to regroup the waveform, or adopt on-the-spotly to change the method of RF module by oneself. SDR still can save other cost, the ability such as the radio resources of dynamic reconfiguration, in order to meet the present systematic demand. Consider the military or commercial base station adopts the single typological reconfigurable circuit board, you can function as the disposition to this base station through the software, make it support the waveform to assign. For example can for deal with 20 signal channel of Waveform A a plurality of allocation of resources of circuit board under base station, and deal with 20 signal channels of Waveform B. If the Apparatus breaks down, for example 10 signal channels supporting Waveform A are unable to work, your all right residual resource of redistribution, make them support 20/10 - 15/15, suitable for application and mixed form that present waveform use while being other. Besides supporting the Multiband, complete trends and can the radio of reconfiguration have a lot of advantages. For example, a part of radio can adopt FEC (forward error correction) Technology comes to match the area of work of this radio. In addition, reconfigurable radio, in order to obtain advantage that innovate immediately, until efficient waveform realize reliable the intersection of security and mechanism. SDR is also expected to reduce development time, because the artificer can be the programming of radio again when the scene goes wrong or changes the agreement. For example, though the agreement can maitain unchanged, algorithm, waveform and modulation mode can be updated with time. Have adopted the structure to SDR of group, can not need to redesign the radio, but obtain these advantages improved and innovated. SCA chassis is in pushing away and entering the army and using SDR, the key to JTRS order is SCA (the Communication architecture of software) Chassis. JTRS is developing this chassis, in order to break the connection between software and hardware, thus dispel and adopt the firm disease that the patent is being realized in the army employs. This system implementation uses the radio and use the soft, hardware resource, these resources of different suppliers' have nothing in common with each other too. SCA lies above the operating system, it is " adhesive " between the software and hardware (Fig. 1) . Its goal is: Any accords with wave form of SCA and can all work in any accord with radio hardware of SCA. The interoperability between this kind of software and hardware is the important consideration content of military application, it is not a simple thing to change the radio on a F-15 fighter. Difficulty of any radio already disposed that SCA hopes to dispel and offer the new radio and staging live effectively.
SCA chassis of today supports the corrugate portability, this is that there are not many and transparent numbers which a developer is pursuing to mutually operate ability. The reason in SCA develops is at this intermediate stage, SCA chassis mainly faces the general-purpose processor, such as Pentium or PowerPC. But, in order to realize high characteristic and cost-effective enough, majority of today design, adopt group adopt group on DSP and specialized hardware (picture 2) of FPGA at the same time on DSP, or FPGA . SCA can meet the portability of the general-purpose processor effectively, but obviously it can't reach the standard of the specialized hardware. It is the most weak ring in SCA to be like this and enough, the reason is, if you can't transplant the software among each platform easily, can not realize required interoperability, or more precisely, realizing and is close to or abundant interoperability.
JTRS is solving the specialized hardware problem. Mainly consider the artificer adopts a linearity or order way to develop the software, but the hardware could reach its peak efficiency during concurrent processing. The developer defines each function method has master influence on efficiency realized finally. Certainly, can C realize, transplant one DSP to and at the FPGA one the intersection of wave and shape that plan, operate at general-purpose processor. All work to be done just operate C code through the suitable tool, this kind of tool can change the function as FPGA and realize. But this step has neglected the advantage of using FPGA main framework: Extensive parallelism. In fact, the only method to utilize this kind of parallelism is to react codes effectively, this transplants one briefly to change into extensive redesign. Also there is doubt in this, namely FPGA will increase the cost in fact. Very difficult settlement of this problem. The most efficient code should be assorted with the used structure: FPGA, DSP, DSP and FPGA mixing, the general-purpose processor,etc.. Though can not almost require the software supplier to set up these code editions obviously each other different, but simplex to realize, it seems to be can effective either while being common. JTRS attempts to solve the specialized hardware problem in SCA specification Version 3.0. Expect it through setting up abstract treatment resources, distribute it to various tasks. However, a lot of developers think this scheme is to face the software, it is not enough to catch up with DSP and FPGA ability. SCA define abstract grade clearly especially, force, supply the commercial result with to explain the norm, and each kind realizes phase difference very big, it is realized that in fact has become exclusive. In addition, in some cases, need extra software abstractly because of realizing, this is enough to totally weaken the advantage of any characteristic of DSP and FPGA. Then, JTRS replies to before SCA of the edition. DSP and FPGA to set up high-efficient foundation that SCA realize compared with high sexual valence in military and business application. The general-purpose processor is very valid while realizing general task, but efficiency is well below the specialized hardware while realizing that there are well-defineds, intensive assumed treatment algorithm, thus bring greater power consumption and larger radio volume, the two are not results wanted. JTRS is seeking to utilize the advantage of specialized hardware, but does not need to truss the software up on exclusive hardware implementation. JTRS is after recombination in 2005, its leaders decide inside solve this problem. On the other hand, though this scheme has limited the participation intensity of the industry in the forming process of standard, but the decision can prevent commercial force from force, change, the change will trust SCA lead to the fact the negative effect to military supplier industry. Use the work of the specialized hardware to be in progress effectively in SCA realizes. For example, realize on FPGA or DSP a main expenses source of SCA is CORBA (public target asks agency's structure) Use. CORBA is the middleware floor between operating system and SCA chassis. It passes the transport data among software target of bus line of a piece of software. It is not a simple thing to realize CORBA on DSP or FPGA. However, several suppliers are developing some methods to realize CORBA on specialized hardware, it makes the hardware look like the software, but does not need not to do reasonably the characteristic. SDR of transition period, for army team, the job of high priority is to make SDR reach such an intensity the most, the radio is no longer the exclusive platform, and JTRS is making this goal become possible in reality constantly with its order, even some military radio suppliers are not fond of expanding the originally narrow job field to the external competition, SCA is such realistic foundation. But in the commercial field, SCA chassis has definite strong points only, perhaps there is no attractive force. Though much business application can obtain the advantage from foundation based on SCA, but perhaps SCA chassis annexes too much interoperability questions different to digest. The totally swappable software and hardware has caused a market with cost variance. Almost there is no advantage in the open design of the commercial field, will only cause and reduce the lateral competition of profits. Prosperity and development in innovation of commercial field, in the radio is employed, the hardware is the master difference origin. SCA chassis forbids introducing the specialized hardware. But with the development of SCA standard, adopt formal standard and oneself as having more high efficiency. In fact, a lot of commercial base stations disposed today have all relied on some software to define the foundation, a considerable amount of functions are to depend on software implementation, mending such as the remote-distance updating of the code, programming base band processor, and can support many kinds of undulate DSP and FPGA. The base station has only used some scrappy things, can be said to be in the meaning with maximum. SDR has extensive adoption ranges. The army is pursuing complete interoperability and ideal realm of the interchange ability. The commercial field is devoted to the equilibrium of the efficiency, function and cost. Because goal and applied difference, just as they are dealing with two kinds of different technology.
