آیا می توان بیش از حامل کردن پهنای باند روی خط قدرت (PLC) به رقابت پرداخت ؟ تجزیه و تحلیل های اقتصادی

Powerline carrier (PLC) communications have been heralded by the FCC as the “3rd wire” to every home, and have matured to the point of field trials and limited deployment. This paper examines the technology from a techno-economic perspective, factoring in regulatory issues and network design (focusing on the United States). Results indicate that PLC does not appear to represent a major disruptive technology, especially from a price-performance perspective. In addition, a baseline stochastic model created for the analysis shows that not only do competition and penetration matter, but locational distribution (i.e., how many consumers can share upstream equipment) is critical in determining PLC's competitiveness.

Broadband penetrations in the United States have, especially until recently, lagged behind those of a number of other OECD countries. In Korea, one of the world leaders, not only are most households online, but 96.5% of these have broadband connectivity ( ITU, 2003). Worldwide, the leading technology used for broadband is DSL (digital subscriber line), followed by cable—which leads in the United States. An emerging technology, powerline carrier (PLC), also known as broadband over powerline (BPL), is envisaged as a new solution that can provide lower costs to consumers. PLC is an access solution that transmits data over electricity wiring while simultaneously carrying electricity. PLC, like most broadband solutions, provides always-on, high-speed connectivity (hundreds of kilobits/s or greater).1 PLC is viewed as especially attractive because of several characteristics. Electricity service is nearly ubiquitous, and so the theoretical coverage from PLC is close to 100% (at least in the US—and most developing countries have higher electricity penetration than telephony). Most consumers have a reasonable expectation of quality and reliability from their power provider.2 In addition, PLC can provide an elegant solution for in-home access and networking, since the signal can reach virtually any outlet in the home. This can provide connectivity to almost any location within the house, in a “plug and play” fashion. For PLC to be successful, it must not only operate successfully from a technology point of view, but also present a viable business case. The two are interlinked, since its market share will depend on its price-performance, i.e., cost as well as throughput. The market space consists of not only well-entrenched alternatives (DSL and cable), but also alternatives such as fiber-to-the-home (FTTH), fiber-to-the-curb (FTTC), and broadband wireless. In addition to an analysis of the technology, and its economic implications, this paper highlights several issues relating to policy. After all, if PLC does not do well in the market, is not that simply a part of the natural competitiveness of the telecom industry? As will be shown, like all issues of telecom, regulation and competition play a vital role. The next section describes PLC technology and its status, highlighting network (power distribution grid) design and its implications. The subsequent section discusses regulations pertaining to PLC, followed by a description of the model created for analysis. It is worth emphasizing that many of the costing numbers are not publicly available, and there will be differences between systems based on different physical infrastructure and designs. Given the great uncertainty in a number of parameters and variables, a stochastic model was created, using a range of parameters, to provide plausible and useful results. After presenting the results, the paper examines sensitivity and robustness of the variables. The concluding sections cover the implications of the analysis, including PLC's possible competitiveness in the market

The model indicates that PLC costs might be about US$32 per month (Fig. 4), based on the assumptions shown. Of course, one might disagree with any parameter value chosen, but sensitivity analysis indicates general robustness of the results presented. Given the fact that many such numbers are either unpublished or unknown (and extrapolating from DSL or cable experience might be somewhat misleading—discussed below), this analysis is a first cut at quantifying the costs of PLC. It is important to remember that these are just costs, based on assumed discount rates for capital. Profits and profitability are not yet factored in.One of the key parameters PLC proponents cite is cost per home passed, with declarations that this is now in the US$100 range.16 However, given the fact that many potential consumers, even if behind a transformer that has the required equipment, may choose not to avail of PLC, a more important question is how many customers per serviced transformer does the company have. Vendors have claimed profitability with just one serviced home per transformer. 17 This model assumes this to be a poor case of user spread, with the best-case scenario with four consumers per LV transformer. Table 2 shows the model calculations, averaging almost 1.7 consumers per distribution (LV) transformer. The total capital costs per consumer (excluding CPE) average about US$85 in the model, assuming an average of 6 homes passed per LV transformer, similar to numbers reported by PLC companies.Marketing and acquisition costs are treated as one-time unshared costs, for simplicity sake. Churn is used as a multiplier that affects not only marketing costs (high churn equates to higher marketing needs) but also it directly affects the time period for amortization of the CPE (most other equipment can be reused amongst a different user in the system). In addition to the one-time costs, there are operating costs such as bandwidth for uplinking. In the model, assuming 2 Mbps rated bandwidth (with the ability to burst higher, of course, just like with cable networks), the monthly per user uplinking cost comes to US$4.2, close to estimates seen for the DSL industry. One result that is robust across most assumption ranges is that operating expenditures (opex) are about 45% of the total costs. There are indications that vendors consider operating costs to be higher than capital costs for almost all the access technologies, showing that the costs of equipment and technology have diminished sufficiently. However, it is unclear if installation costs are bundled as capital expenses or treated as operational costs. In addition, the numbers used for maintenance and other operating costs might differ, especially for the case of uplinking bandwidth costs.18 Given the increased trend in peer-to-peer traffic, it is not unreasonable to expect uplinking costs to remain high. 5.1. Sensitivity and robustness Given the wide range of monthly costs seen in Fig. 3, sensitivity analysis is very important for determining the robustness of the model. The analysis uses stochastic modeling as well as parametric modeling for this. Fig. 5 shows the results of an importance analysis for the relative importance of the varying input parameters.19 The most important variable, under the assumptions of Table 1, is the time period for amortization of the equipment. Given the fast-changing nature of the telecom industry, even though the equipment should have a longer physical life than assumed, the median value for economic purposes is assumed to be 5 years. However, in a very competitive environment, instead of the nominal 5 years, equipment might need to be amortized sooner, and the implications are non-linear.20Table 3 shows the impact of amortization period on the economics, assuming median values for other parameters.As expected, user distribution is one of the most important factors when determining monthly costs, followed by the shared distribution transformer concentrator/coupler capital costs. Other than the LV transformer concentrator capital costs, most other capital expenditures have relatively low impact on monthly costs. The uplink cost is unlikely to be the hands of the PLC service provider, and the statistical multiplexing (oversubscription) ratio is a business decision the provider will need to take depending on the quality and perceived quality for the end users. Of course, in a competitive environment, a service provider will need to ensure high effective throughputs for end users. This is even more important when high-end (video) services are envisaged. Other important factors such as market share, acquisition/marketing costs and even cost of capital all depend on the competitive nature of the business. Given improvements in DSL and cable technologies, as well as emerging competition from FTTH and wireless, it would be safe to expect increasing competitiveness and churn. Churn might likely have implications for marketing costs, but this model, in the absence of data, does not account for that. The impact of market share and user spread on monthly amortized capex can be seen in Table 4.Examining the sensitivity to two important factors, user spread and LV concentrator capital costs, Table 5 shows wide variation in monthly costs based on the assumptions. A similar importance of market share was also seen in a DSL and cable model by Fryxell (2002), where low market shares could lead to a fourfold increase in annualized capital costs. Even considering an optimistic case for capital costs within the near term, the monthly cost of the PLC system is unlikely to be dramatically lower than US$25 per month (Table 6).The results, of course, have the expected provisos attached to them. For example, if there is significant signal interference, providers would have to adjust the signal strength, reducing the throughput or requiring further repeaters. If users consume more bandwidth than projections infer (e.g., due to increased peer-to-peer applications, or video/video-conferencing), this impacts uplinking costs and might even require a redesign since the MV line running PLC has limited total bandwidth. However, technology costs could fall dramatically, especially with higher volume. In addition, within a region or niche market, the competitive pressures might be much lower, allowing for higher market share and greater sharing of equipment, marketing, and maintenance costs amongst subscribers. 5.2. Cable, DSL, and competition Many comparative analyses suffer from Parmenides Fallacy, which is comparing the future to the present, instead of comparing it to alternative futures. At CITI's PLC III Workshop, an industry representative, when questioned about economics, said PLC does not need to be cheaper than the alternatives, it just needs to be profitable at offered prices. This appears short-sighted in that entrenched alternatives can easily lower their prices to compete. Cable has similar data bandwidth today, also shared, but companies justified their Internet services rollout and investment of billions of dollars due to the large base of users for video services. There are many indications that the prices for cable and DSL will fall dramatically in the next few years and their performance will continue to improve. Already, DSL has cut its prices to US$30–35 per month in many regions, driven by competition from cable systems. In addition, the capital expenditure for a DSL system is dropping dramatically, and is now well below US$100 per user, including the CPE (DSL Prime, 2004). (In the analysis model, such capital costs would lead to amortized capex costs of a quarter of the baseline PLC capital costs, or just US$2.2 per month! Of course, these are equipment capital costs only, excluding any installation or line conditioning charges.) Examining DSL prices in Japan and Korea, these are already below US$25–30 per month retail, that too for much higher speeds. 21 These systems are based on pre-standard VDSL, offering tens of Mbps per user. Use of such variants of DSL in the US is some time away due to both longer distances and the physical plant design. But, if and when DSL upgrades its speeds, these would be unshared speeds at least in the access portion of the network. Total bandwidth is important when considering the applications and services consumers demand from their providers. Given competition amongst access technologies, many analysts believe the “triple play” of services (voice, video, and broadband data) is important for not only gaining customer loyalty and traction, but for justifying the investments required for upgraded speeds. Of the three major technologies, cable systems offer the highest bandwidth, albeit shared. However, with newer standards, such as DOCSIS 1.1 and 2.0, cable is now ready to offer voice services. DSL, by definition, is geared to providing voice services, but typically lacks the bandwidth to offer even switched video (especially in the US). Considering 2–6 Mbps requirements for compressed video, only newer DSL variants can offer appropriate bandwidth. To offer voice services, PLC would require quality-of-service (QoS) mechanisms that are today not standardized, but this can be expected shortly. However, the total shared bandwidth might be constrained for widespread video usage. Cable systems, though also shared, can increase the effective throughput through several means, including reducing the physical sharing of the system, changing some bands used for TV into data, and also opening higher frequencies on the cable through newer technology equipment. In the interim, cable systems have faced difficulties with consumers overusing shared bandwidth, an issue that might plague PLC as well.22 PLC will likely take at least one or two more years to reach 100 Mbps of shared bandwidth in deployment. In addition, switched video is likely to raise operating and uplink and costs, compared to best effort data connectivity and high-quality unidirectional broadcast for video through cable. This raises the issue of timing and window of opportunity. At one level, PLC providers would want to wait until the technology is slightly more robust and the raw speeds have increased to at least 100 Mbps. On the other hand, cable and DSL continue to gain deployment and penetration. The window for PLC becomes more limited when analyzing the longer-term horizon, which includes FTTH or FTTC. While in the United States FTTH is some years away, in Japan it is already an emerging competitor, and expected to become mainstream within a few years. FTTH offers an order or two of magnitude more bandwidth, and greater future proofing. Its main limitation is on the physical infrastructure—laying fresh fiber is expensive, and greenfield FTTH deployments are estimated at capital investments of over US$1,000 per user (conventional wisdom). On the other hand, there might be synergies between the so-called deep fiber and PLC, whereby a utility/provider could use PLC as a last-hop solution. This makes even more sense if there is a major service provider looking to expand the broadband market while not being beholden to the incumbents (ideal candidates include Yahoo/MSN/Earthlink or long-distance companies who lack local physical presence such as AT&T or MCI).