High throughput MIMO-OFDM WLAN for urban hotspots

2007 IEEE Mobile WiMAX Symposium

Strauch

et al. 2007

Abstract-WiMAX (802.16e) is technically capable of offering city-wide broadband connections to a high number of mobile terminals. The technology has strong industrial support, however a number of challenges remain to be resolved. Major concerns include battery life for mobile terminals, balancing support for high velocity and high data-rate, and increasing area coverage. Relay technology is a promising approach to address these challenges. Due to limited radio resources, it is necessary to consider radio resource efficiency. This paper presents a de-tailed analysis of relay efficiency with and without resource sharing. To enhance spectral efficiency, a directional distributed relaying architecture is proposed for interference elimination and avoidance.

Section: Hz Bpsmentioning

confidence: 99%

Study of radio resource sharing for future mobile WiMAX applications with relays

Sun

2007 IEEE Mobile WiMAX Symposium

Strauch

et al. 2007

“…MIMO is seen as a critical component in future developments of mobile WiMAX. Suitable MIMO orientated link adaptation strategies are critical to exploit the wide of range of MIMO systems and channel conditions [4]. For example, STBC offers diversity gain, but cannot improve capacity without the use of Adaptive Modulation and Coding (AMC).…”

Section: Introductionmentioning

confidence: 99%

“…For example, STBC offers diversity gain, but cannot improve capacity without the use of Adaptive Modulation and Coding (AMC). SM combined with higher order modulation schemes can increase the peak throughput, but such schemes require extremely high SNR levels [4]. In practical urban cells it will be difficult to exploit SM at the cell edge.…”

Section: Introductionmentioning

confidence: 99%

Performance Evaluation of Mobile WiMAX with MIMO and Relay Extensions

2007 IEEE Wireless Communications and Networking Conference

Nix

Sun

et al. 2007

Abstract-The latest mobile WiMAX standard promises to deliver high data rates over extensive areas and to large user densities. More specifically, data rates are expected to exceed those of conventional cellular technologies. The IEEE 802.16e Wi-MAX standard enables the deployment of metropolitan area networks to mobile terminals in non-line-of-sight radio environments. Current concerns include leveraging high data rates, increasing area coverage, and competing with beyond 3G networks. Based on the IEEE 802.16e wirelessMAN-OFDMA (Orthogonal Frequency Division Multiple Access) physical (PHY) layer air-interface, this paper presents a physical layer study of MIMO enabled mobile WiMAX in an urban environment. The radio channels are based on those developed in the European Union IST-WINNER project. Results are given in terms of system throughput and outage probability with and without relays for a range of SISO, MISO and MIMO architectures. Results show that satisfactory performance cannot be achieved in macrocells unless radio relays are used in combination with MIMO-STBC.

“…Spatial correlation between subchannels in the MIMO channel matrix limits the level of spectral efficiency that can be achieved in practice. Performance is a function of parameters such as the K-factor, the spread in the angles of departure (AoD) and the angles of arrival (AoA), the antenna-element separations, the delay spread (DS), and the signal-to-noise ratio (SNR) [8], [9]. The theoretic MIMO capacity can be predicted by passing the channel data into the Foschini capacity equation [10], [11].…”

mentioning

confidence: 99%

“…Higher order modulation schemes will increase the link throughput but require a higher SNR to achieve a low packet error rate (PER). Space-time block codes (STBCs) provide a strong diversity gain (which is desirable at a low SNR) but cannot increase the link throughput without the use of adaptive modulation and coding (AMC) [9]. Previous work has already considered the application of adaptive MIMO [12]- [16].…”

mentioning

confidence: 99%

MIMO–OFDM WLAN Architectures, Area Coverage, and Link Adaptation for Urban Hotspots

IEEE Trans. Veh. Technol.

Nix

Tameh

et al. 2008

Self Cite

Abstract-This paper considers the suitability of a range of multi-input-multi-output (MIMO) orthogonal frequency-division multiplexing architectures for use in urban hotspots. A ray-tracing propagation model is used to produce realistic MIMO channel data. This information is used to determine the expected throughput and area coverage for various physical (PHY) layer schemes. Site-specific throughput predictions are generated in a city-center environment. Link adaptation (LA) is shown to play a key role in the choice of space-time algorithm, the use of adaptive modulation and coding, and the number of antennas employed at both ends of the radio link. No single PHY layer scheme is suitable to cover the entire coverage area. Results demonstrate the need for MIMO LA under a wide range of channel conditions. For the area under test, 2% of covered locations selected a spatial multiplexing (SM) scheme, 50% selected a space-time block coding (STBC) scheme, and 48% selected a hybrid SM/STBC scheme. With suitable power control and LA, for the scenario under consideration, high peak capacities and good geographic coverage were achieved.Index Terms-Link adaptation (LA), orthogonal frequencydivision multiplexing (OFDM), power control, propagation, space-time block codes (STBCs), spatial multiplexing (SM).