This paper investigates the potential of millimeter wave (mmW) frequencies (30-300 GHz) for next-generation micro- and picocellular wireless networks, addressing the severe spectrum shortage in conventional cellular bands. Using real-world measurements at 28 and 73 GHz in New York City, the authors derive detailed spatial statistical models of the channels and assess the performance of mmW systems in dense urban deployments. Key findings include: 1. **Path Loss**: The omnidirectional path loss at mmW frequencies is approximately 20 to 25 dB higher compared to current cellular frequencies, but this can be compensated by increasing antenna gain through beamforming, potentially reducing effective path loss. 2. **Spatial Clusters**: Measurements indicate that energy arrives in clusters from multiple angular directions, with up to four clusters observed at many locations. This suggests the possibility of spatial multiplexing and diversity gains. 3. **System Capacity**: Applying the derived channel models to a standard cellular evaluation framework, the authors predict that mmW systems can offer at least an order of magnitude increase in system capacity compared to current 4G cellular networks, even without increasing cell density. 4. **Outage Robustness**: The system performance appears robust to outages, provided they are similar or slightly worse than observed in the NYC measurements. However, significantly worse outages can impact cell edge rates. 5. **Beamforming and MIMO Gains**: The paper discusses the gains from beamforming and spatial multiplexing in mmW systems, showing that long-term beamforming can achieve gains close to the maximum possible, with directional isolation being a significant advantage. 6. **Spatial Degrees of Freedom**: The presence of multiple path clusters indicates the potential for spatial multiplexing, with two or three spatial dimensions needed to capture most of the channel energy, suggesting the possibility of significant MIMO gains. Overall, the paper provides a comprehensive assessment of mmW systems, highlighting their potential for high-capacity wireless networks in urban environments.This paper investigates the potential of millimeter wave (mmW) frequencies (30-300 GHz) for next-generation micro- and picocellular wireless networks, addressing the severe spectrum shortage in conventional cellular bands. Using real-world measurements at 28 and 73 GHz in New York City, the authors derive detailed spatial statistical models of the channels and assess the performance of mmW systems in dense urban deployments. Key findings include: 1. **Path Loss**: The omnidirectional path loss at mmW frequencies is approximately 20 to 25 dB higher compared to current cellular frequencies, but this can be compensated by increasing antenna gain through beamforming, potentially reducing effective path loss. 2. **Spatial Clusters**: Measurements indicate that energy arrives in clusters from multiple angular directions, with up to four clusters observed at many locations. This suggests the possibility of spatial multiplexing and diversity gains. 3. **System Capacity**: Applying the derived channel models to a standard cellular evaluation framework, the authors predict that mmW systems can offer at least an order of magnitude increase in system capacity compared to current 4G cellular networks, even without increasing cell density. 4. **Outage Robustness**: The system performance appears robust to outages, provided they are similar or slightly worse than observed in the NYC measurements. However, significantly worse outages can impact cell edge rates. 5. **Beamforming and MIMO Gains**: The paper discusses the gains from beamforming and spatial multiplexing in mmW systems, showing that long-term beamforming can achieve gains close to the maximum possible, with directional isolation being a significant advantage. 6. **Spatial Degrees of Freedom**: The presence of multiple path clusters indicates the potential for spatial multiplexing, with two or three spatial dimensions needed to capture most of the channel energy, suggesting the possibility of significant MIMO gains. Overall, the paper provides a comprehensive assessment of mmW systems, highlighting their potential for high-capacity wireless networks in urban environments.