Source: https://www.fcc.gov/document/dect-forum-1920-1930-mhz
Timestamp: 2015-08-05 04:29:02
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DECT Forum (1920-1930 MHz)
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FCC 12-33
Amendment of Part 15 of the Commission’s Rules )
Regarding Unlicensed Personal Communications )
Service Devices in the 1920-1930 MHz Band
REPORT AND ORDER Adopted: March 22, 2012
By this action, we modify Part 15 of the rules governing the operation of Unlicensed Personal Communications Service (UPCS) devices in the 1920-1930 MHz frequency band (UPCS band) to promote more efficient use of the UPCS band and to facilitate the introduction of a new generation of unlicensed devices capable of supporting broadband connectivity using Digital Enhanced Cordless Telecommunications (DECT) technology.1 Specifically, we eliminate the least-interfered channel monitoring threshold for UPCS devices and reduce the number of duplex system access channels that a UPCS device must define and monitor from 40 to 20 channels in order to use the least-interfered channel access method. These changes will provide UPCS devices, particularly those designed to transmit with wider bandwidths, access to more usable channels (i.e., combined time and spectrum windows) than are permitted under the existing rules and unleash innovative cordless broadband technologies in the UPCS band, while limiting the potential for causing interference to other devices. We also modify the rules to remove outdated provisions and to make other minor updates. II.
The 1920-1930 MHz band is allocated to Fixed and Mobile services on a primary basis and is designated for use by UPCS devices on an unlicensed basis.2 Currently, the major use of the 1920-1930 MHz band is for unlicensed cordless telephones that operate under Part 15 of the Commission’s rules.3 The Part 15 rules provide that the 1920-1930 MHz band may be used for both asynchronous (generally data) and isochronous (generally voice) UPCS devices, with maximum and minimum emission bandwidths of 2.5 megahertz and 50 kilohertz, respectively.4 UPCS devices operating 1 DECT-based radio technology facilitates voice, data, and networking applications with range requirements up to a few hundred meters.
2 See 47 C.F.R. §§ 2.106, 15.301.3 See DECT Solutions at http://www.dect.org. See also Plantronics, Inc. (Plantronics) Comments at 1.4 See 47 C.F.R. §§ 15.303(a) and (d), 15.323(a). UPCS systems may sub-divide the 2.5 megahertz emission bandwidth as long as the sub-divided emission bandwidth is greater than or equal to 50 kilohertz. Under the Part 15 rules, a UPCS channel is defined as the combined time and spectrum windows that a transmission is intended to occupy. 47 C.F.R. § 15.323(c). Spectrum window is defined as the amount of spectrum equal to the intended emission bandwidth in which operation is desired. 47 C.F.R. § 15.303(h).
in the 1920-1930 MHz band are subject to the general conditions of operation for Part 15 devices in that they may not cause harmful interference to authorized radio services and must accept any interference received.5
To facilitate the sharing of spectrum in the UPCS band, the current rules require use of a “spectrum etiquette” that specifies a process for monitoring the time and spectrum windows that a transmission is intended to occupy for signals above a defined threshold (a “listen-before-transmit” protocol). To protect UPCS devices already using particular time and spectrum windows from transmissions from another device, each UPCS device must monitor the combined time and spectrum windows that it intends to use before beginning transmissions and defer use or find other spectrum windows if the monitored signal level is above the threshold.6 Transmissions may commence with the same emission bandwidth in a monitored time and spectrum window without further monitoring if no signal greater than 30 decibels (dB) above thermal noise is detected in the chosen window.7 Alternatively, if the UPCS system defines and the UPCS device can monitor at least 40 duplex system access channels, the UPCS device may access the time and spectrum windows with the lowest signal level below a threshold of 50 dB above thermal noise (henceforth referred to as the “least-interfered channel access method”).8 If the initially selected combined time and spectrum windows are unavailable, the UPCS device may either monitor and select different windows or seek to use the same windows after waiting a randomly chosen amount of time between 10 and 150 milliseconds.9 4.
On May 6, 2010, the Commission adopted a Notice of Proposed Rulemaking (UPCS Band NPRM) in this proceeding that proposed changes designed to allow UPCS devices to access additional usable channels.10 The Commission took this action in response to a petition for rulemaking filed by the DECT Forum, an industry association that promotes digital cordless radio technology for short-distance voice and data applications.11 In the UPCS Band NPRM, the Commission proposed to increase the least-interfered channel monitoring threshold from 50 to 65 dB above thermal noise andsought comment on whether some alternative value or elimination of the threshold would be more 5 See 47 C.F.R. § 15.5(b). 6 See 47 C.F.R. § 15.323(c)(1)-(12). See also n.4, supra. To prevent the monopolization of UPCS-band channels by one or more devices, the Commission’s rules also include UPCS transmission time limits. See 47 C.F.R. § 15.323(c)(3). The access threshold, transmitter power limits, and transmission time limits are designed such that frequency and time reuse both within a system and between systems are possible for indoor operations.
7 See 47 C.F.R. § 15.323(c)(1)-(3). UPCS devices that have a power output lower than the permitted maximum may increase their monitoring threshold by 1 dB for each 1 dB that the transmitter power is below the permitted maximum. See 47 C.F.R. § 15.323(c)(9). Thermal noise power, typically referred to as thermal noise, is produced by the random thermal agitation of electrons in an electronic circuit. The thermal noise power (in dBm) for a given emission (i.e., channel) bandwidth is defined by the formula 10 log (1000 x kTB), where k is Boltzmann’s Constant (1.38 x 10-23 W/Hz/K); T is the ambient temperature in degrees Kelvin (e.g., 298º K at room temperature (77º F)); and B is the emission bandwidth of the device in Hertz. See 47 C.F.R. § 15.303(j). The thermal noise in a 50 kilohertz channel at room temperature is -127 dBm.
8 See 47 C.F.R. § 15.323(c)(5). 9 See 47 C.F.R. § 15.323(c)(6).10 See Amendment of Part 15 of the Commission’s Rules Regarding Unlicensed Personal Communications Service Devices in the 1920-1930 MHz Band, ET Docket No. 10-97, RM-11485, Notice of Proposed Rulemaking, 25 FCC Rcd 5118 (2010) (UPCS Band NPRM).
11 See “Petition for Rulemaking to coordinate the service rules of the UPCS Band with those ultimately adopted for the AWS H Block,” Petition for Rulemaking, filed Aug. 15, 2008, by DECT Forum, placed on Public Notice for comment on Sept. 4, 2008 (Report No. 2873; RM-11485) (DECT Forum Petition).
appropriate.12 The Commission also proposed to reduce the number of channels that must be defined and monitored under the least-interfered channel access method from 40 to 20 channels.13 It additionally sought comment on removing Sections 15.303(b) and (e), 15.307, and 15.311 regarding coordination with UTAM, Inc., since the relocation of incumbent fixed services from the band is now complete.14 The Commission further sought comment on a number of proposed updates to the Part 15 UPCS rules regarding measurement procedures and definitions.15 Eight parties filed comments in response to the UPCS Band NPRM; these parties all strongly support the Commission’s proposals.16 No parties filed reply comments. III.
DISCUSSION 5.
Based on our analysis of the record, we decide to eliminate the 50 dB above thermal noise monitoring threshold for UPCS devices. Without this threshold, after monitoring the required minimum number of channels, UPCS devices may use the combined time and spectrum windows with the lowest signal level, rather than using only those windows with the lowest signal level below 50 dB above thermal noise. Coupled with a reduction in the number of channels that must be monitored, elimination of this threshold will permit greater utilization of the UPCS band.17 For example, manufacturers could optimize cordless telephones for higher-density applications, such as office environments. These changes are also expected to encourage manufacturers to introduce innovative products and services using Internet 12 See UPCS Band NPRM, 25 FCC Rcd at 5124 ¶ 14. The UPCS Band NPRM acknowledged that the DECT Forum and others asserted that an increase in the least-interfered channel monitoring threshold is needed so the out-of-band emissions from future devices transmitting in the 1915-1920 MHz Advanced Wireless Service (AWS) band –commonly known as the “H Block” – will not restrict UPCS devices’ access to a major part of the 1920-1930 MHz band. The UPCS Band NPRM noted that the issue of out-of-band emissions for the “H Block” was being addressed in a separate proceeding and thus did not solicit comments on nor make any decision with respect to this issue. See UPCS Band NPRM, 25 FCC Rcd at 5122 ¶ 9, 5125-26 ¶ 17. Nonetheless, several commenters on the UPCS Band NPRM express support for increasing the monitoring threshold for this reason. See DECT Forum Comments at 1, 4; DSPG Comments at 1-3; Gigaset Comments at 1; Panasonic Comments at 2-3; Plantronics Comments at 2-3; TIA Comments at 5; and VTech Comments at 2-3.
13 See UPCS Band NPRM 25 FCC Rcd at 5123-25 ¶¶ 12-16.14 See UPCS Band NPRM 25 FCC Rcd at 5126-27 ¶ 18. UTAM, Inc., which the Commission designated to coordinate and manage the transition of the 1910-1930 MHz band from incumbent fixed microwave operations to UPCS use, is a non-profit corporation composed of representatives from a broad range of UPCS equipment manufacturers that the Unlicensed PCS Ad Hoc Committee for 2 GHz Microwave Transition and Management (UTAM) incorporated in July 1993. 47 C.F.R. § 15.307(a). See also Amendment of the Commission’s Rules to Establish New Personal Communications Services, GEN Docket No. 90-314, Second Report and Order, 8 FCC Rcd 7700, 7736 n.74, 7783 ¶ 202 (1993) (Broadband PCS Second R&O); UTAM Reply Comments, GEN Docket No. 90-314, ET Docket No. 92-100, filed July 20, 1993, at 10 and Appendix A, Certificate of Incorporation of UTAM, Inc.
15 See UPCS Band NPRM at 5127 ¶ 19. 16 See generally DECT Forum Comments; DSP Group, Inc. (DSPG) Comments; Gigaset Communications GmbH (Gigaset) Comments; Panasonic Corporation of North America (Panasonic) Comments; Plantronics, Inc. (Plantronics) Comments; Telecommunications Industry Association (TIA) Comments; Uniden America Corporation (Uniden) Comments; and VTech Communications, Inc. (VTech) Comments. Comments in this proceeding, ET Docket No. 10-97, RM-11485, may be viewed in the Commission’s Electronic Comment Filing System, which can be found on the Commission’s web site at http://fjallfoss.fcc.gov/ecfs/comment_search/input?z=u67ee and accessed under Doing Business Public Comment (ECFS) on the Commission’s main web page at https://www.fcc.gov.
17 See DECT Forum’s Petition, Annex I, at 7; Panasonic Comments at 3-4; Plantronics Comments at 2; TIA Comments at 5-7; Uniden Comments at 2; and VTech Comments at 3-4. 3
protocol connectivity to combine access to broadband and telephony applications in a new generation of cordless devices.18
First, we conclude that the 50 dB above thermal noise least-interfered channel monitoring threshold for UPCS devices operating in