Difference between MMDS vs LMDS Broadband Wireless Technologies

LMDS and MMDS are broadband wireless technologies designed to provide high-speed internet, voice and video services. LMDS (Local Multipoint distribution service) excels in urban environments with high-density populations, offering high bandwidth and robust sectorization capabilities. On the other hand, MMDS (Multichannel Multipoint Distribution Service) is suited for wider geographic coverage in suburban and rural areas, leveraging lower frequency bands for extended reach and cost-effective deployment.

MMDS

The broadband term MMDS stands for Multichannel Multipoint Distribution Service. It is used as replacement of cable TV service provider. MMDS is used to cover rural or suburban areas where it is not possible to reach by broadcast and cable TV operators.
Refer MMDS Architecture➤.

MMDS architecture

The key features of MMDS are as follows.
➨Frequency range : Operates in low frequency bands typically 2.5 GHz and 3.5 GHz bands.
➨Architecture : Supports P2MP (Point to Multipoint) and P2P (Point to Point) topologies.
➨Coverage : Covers larger geographical areas with hub tower range of approximately 35 miles.
➨Uses less specialized RF equipments in larger quantities at lower frequencies, reducing costs.
➨More susceptible to interference from other MMDS and TV applications due to shared bands.
➨Requires precise planning for large scale deployment and upstream bandwidth management.

LMDS

The broadband term LMDS stands for Local Multipoint distribution service. It is used for providing TV and 2-way internet service similar to MMDS. LMDS is well suited for high density urban environments requiring high bandwidth and extensive coverage management. Refer LMDS Architecture➤.

LMDS architecture

The key features of LMDS are as follows.
➨Frequency range : Operates above 20 GHz, typically at 28 GHz or 38 GHz frequencies.
➨Architecture : Utilizes P2MP (Point to Multipoint) topology, with capability to interface with P2P (Point to Point) and TV systems.
➨Coverage : Typically covers smaller areas, with a base station (BS) range up to 5 miles.
➨Offers high bandwidth suitable for wide range of applications such as voice, IP and data services.
➨Network : The LMDS network requires specialized RF equipment for operations, including RF Up/Down converters and optical interfaces. Supports sectorization to manage large user capacities in densely populated urban areas. Requires a robust fiber based infrastructure with SONET, optical links, and CO equipment.

Frequency allocation for MMDS and LMDS

2.15 GHz to 2.68 GHz frequency band is allocated for MMDS; five of these bands in these bands are already used in USA. OFDM modulation technique with bandwidth of 6 MHz composed of 512 sub carriers is used for MMDS. The sub carrier spacing is about 12 KHz. It is also used for providing 2-way broadband data or internet service.

About 30GHz to near about 40GHz bands are used for LMDS. Mainly used in USA, Europe and other countries.

Advantages and disadvantages of LMDS and MMDS

Following are the advantages and disadvantages of LMDS and MMDS.

•  As mentioned both are used for TV and 2-way internet service using fixed wireless access.
•  Due to lower RF frequency range, MMDS provides lesser BW compare to LMDS.
• Higher data rates are also going to be achievable owing to OFDM technology advancement with MMDS.
• But MMDS is ideal for small business enterprises and residential users and LMDS is used for larger businesses. LMDS offers higher data rates.
•  MMDS signal can cover long distances and hence used in large cell network scenario. LMDS signal can cover short distance from Base Station equipments.
•  Due to larger wavelength, MMDS signals are less susceptible to rain and absorption losses compared to shorter wavelength LMDS signal.

Difference between LMDS and MMDS

Let us summarize tabular difference between LMDS and MMDS below.


Specifications LMDS MMDS
Full Form Local Multipoint Distribution Service Multichannel Multipoint Distribution Service
Architecture The LMDS architecture consists of NOC (Network Operation Center), BS, CPE and Fiber backbone. It has cellular like architecture. The MMDS architecture consists of tall antenna tower, backbone internet connectivity using router and network management system. It has microwave link like architecture.
Frequency of operation 28 GHz, 38 GHz 2.5 GHz, 3.5 GHz
RF Equipment Cost Higher Lower
Interference susceptibility Lower Higher (from other MMDS and TV applications)
Rain attenuation Higher Lower
Distance coverage Good more smaller distances. (2 to 8 Km) Covers larger distance. (50 to 100 Km)
Number of cells more very few
Data rate 1 to 10 Mbps upto 2 Mbps
cost CPE cost and deployment cost is medium to high. CPE cost and deployment cost is low compare to LMDS.

Conclusion : In summary, the choice between LMDS and MMDS hinges on factors such as coverage requirements, bandwidth needs, cost considerations, deployment flexibility, interference levels, weather resilience, regulatory requirements and specific application scenarios. Evaluating these parameters helps stakeholders determine the most suitable technology for their broadband deployment objectives.


LMDS and MMDS Tutorial

Refer tutorial on LMDS and MMDS >> which describes architectures, advantages and disadvantages including their system features.

Tutorials on wireless communication technologies


What is Difference between

RF and Wireless Terminologies