Nortel

6 September 2007

Radio Spectrum Policy and Planning Ministry of Economic Development
Email: radiospectrum@med.govt.nz

Radio Frequency Auction: 2.3 GHz and 2.5 GHz Bands

Nortel welcomes the opportunity to comment on the Discussion Paper dated August 2007.

Nortel is a recognized leader in delivering communications capabilities that enhance the human experience, ignite and power global commerce, and secure and protect the world's most critical information. Our next-generation technologies, for both service providers and enterprises, span access and core networks, support multimedia and business-critical applications, and help eliminate today's barriers to efficiency, speed and performance by simplifying networks and connecting people with information. Nortel does business in more than 150 countries.

Nortel has been a major contributor to the development of the mobile WiMAX Standard (802.16 (e)) with contributions in relation to MIMO and OFDMA. These are the basis for the high spectral efficiency of mobile WiMAX and the ability to provide mobile broadband networks with the average throughput per subscriber in excess of 1 Mbps.

There is a growing view that mobile broadband will be of greater importance for consumers and businesses than fixed broadband. Nortel believes that, just as voice traffic is moving from fixed to mobile networks, mobile broadband will become the most common access means for many applications.

These mobile broadband networks can be provided using existing 3G technologies but mobile WiMAX offers major improvement in throughput as well as including quality of service to support VoIP and other real-time applications, and a broadcast/multicast ability to allow the efficient delivery of fixed and mobile TV.

Comments on Issues Raised in the Discussion Paper

Minimum Frequency Requirements for WiMAX Provision (paras 32 and 33)

Nortel is of the view that 30MHz of TDD spectrum (plus a provision for guard bands) is sufficient to allow economic deployment of networks in urban areas and to provide the capacity required for the services that will be delivered by mobile broadband in the next 5 to 7 years. In the longer term, it expects that more spectrum will be required or that more base stations will have to be added to provide the needed capacity.

Lack of Technology Certainty (paras 34 and 35)

Nortel does not understand the intent of these comments. WiMAX, as with almost all current telecommunications technologies, is not standing still and development of the underlying standard to add new features and capabilities is just “business as usual”. To provide the certainty needed for the investments needed to develop commercial interoperable products, the WiMAX Forum has developed certification profiles and a certification process for both fixed and mobile WiMAX.

WiMAX is being deployed in both the 2.3 and 2.5 GHz bands and both network equipment and CPE is available for both bands. The dominant band will be determined by spectrum availability for mobile broadband technologies across the globe, however, the 2.3 and 2.5 GHz bands will both be major bands for WiMAX.

WiMAX allows operators to follow different business models to cellular IMT technologies, even though it is currently being evaluated by the ITU-R for addition to the list of IMT technologies. The existing IMT technologies come from a voice centric background with data capability added, whereas WiMAX was designed as a wireless IP data network with voice being an application carried on that network. WiMAX is expected to be included in many consumer electronics devices that would benefit from connectivity, with many operators being far less focused on the handset model of current cellular technologies.

There is no need for those thinking about using WiMAX in New Zealand to be concerned about equipment being available for 2.3 or 2.5 GHz bands and re-tuning will not be required because the equipment is available in the respective bands.

Size and Location of Managed Spectrum Park or Parks (paras 47 to 50)

The amount of spectrum required for WiMAX services in a managed park depends on the locations where the services will be provided and the range of services anticipated. If it is expected that WiMAX in managed parks will directly compete with WiMAX in licensed spectrum with a full range of services in urban areas being provide 24x7, then 35 MHz (including guard band) could be required for each user of the park depending on the number of customers to be served and the performance that is offered.

TDD and FDD technologies (para 34)

TDD and FDD can coexist in the same band, but as shown by the WiMAX Forum paper “Service Recommendations to Support Technology Neutral Allocations: FDD/TDD Coexistence” and the Ofcom paper ”Award of available spectrum: 2500-2690 MHz, 2010-2025 MHz” that was released on 1 August 2007, it may be necessary to put in place measures such as guard bands or lower power levels in some situations. This is of course similar to coexistence issues with many technologies that are part of the day-to-day issues of spectrum management. It should be recognised that interference will often mean a lower level of performance, rather than service denial, and may not even be noticed due to the bursty nature of data traffic. However, effective utilization of bandwidth calls for TDD use by all operators.

Guard Bands (paras 55 to 59)

Nortel supports the Ministry’s preference for management right holders to take responsibility for managing interference but believes that some basic limits such as out of band emissions need to be set as part of the process. There also may be a need for a reserve power so the Ministry can intervene if adjoining right holders fail to reach agreement.

Responses to Questions

Question 1: Considerations Relating to Lot Design

a. Expected technical developments and likely demand

See above

b. Size and location of managed spectrum park or parks

As discussed above, the spectrum requirements will depend on the types of services that are expected to be provided, the number of customers to be served by each base station and the environment within which this is to happen (urban, rural etc). It will also depend on the interference mitigation techniques applied such as synchronisation, guard bands, co-location, channel width, power limits etc. Page 3 of 5

c. Acquisition limits

No comment

d. Technical issues

The WiMAX Forum Profiles anticipate that the 2.3 GHz band will be used for TDD. A TDD profile currently exists for the 2.5 GHz band and there could be a requirement for an FDD profile in the future.

TDD and FDD can share the same band with suitable technical arrangements as discussed above. Nortel notes that the use of this band for IMT is not mandated by the ITU-R, it is one possible use and other technologies are anticipated. Also, the draft ITU-R WP 8F document proposes 3 arrangements for the band including a flexible mix of FDD and TDD. But, Nortel does recommend that 120 MHz pairing be guaranteed for any FDD paired spectrum in the band.

Adequate sized guard bands will make use of allocated spectrum for service more efficient and remove potential uncertainty about the cost of interference mitigation techniques and their impact on deployment options and the data rates that can be provided. A 5 MHz band between TDD operators is suitable and Nortel agrees with the proposal that this spectrum under appropriate technical conditions be managed by right holders so they can use the spectrum when this use remains within related technical parameters or is mutually agreed with the affected adjoining right holder.

Question 2: Proposed Lot Design

2.3 GHz

Nortel supports the lot design for the 2.3 GHz band in Options A and C. It believes that Option B is too likely to lead to an inefficient spectrum allocation and/or artificially inflate prices during the auction as participants seek to obtain lots like those proposed in Options A and C but are blocked by people bidding on single lots.

2.5 GHz

Nortel does not strongly support any of the options proposed for this band but has a slight preference for the Options A and C(ii). A better option in Nortel’s view is that the management right allocation process allow the mix of FDD and TDD to be determined as Page 4 of 5 part of the process, as in C(ii) but modified to provide a 120 MHz pairing for any FDD spectrum pairs. This is part of the proposed arrangements in the Ofcom consultation paper and Nortel strongly recommends that the Ministry consider such a modification. Care may be needed in the lot design as all lots will not be of equal value.

Question 6: Use or Lose Provisions

Nortel agrees that use or lose provision are important to ensure that spectrum is not hoarded.

Question 8: Managed Spectrum Parks

b. Many technologies such as WiMAX are intended for spectrum which is under the exclusive control of the network provider and hence interference management techniques such as “listen before talk” are not required and unlikely to be part of technology systems that are developed. Even for shared spectrum technologies, such as UWB, the efficacy of “detect and avoid” has yet to be demonstrated.

Nortel can expand its views if that would assist the Ministry with its decisions.

Yours sincerely

Graeme King
Specialist,
Regulation and Policy